From b1545fe5eff229b3b04efb5e791954c40c630780 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 9 Apr 2018 08:52:20 -1000
Subject: [PATCH] Accept new baselines

---
 .../reference/conditionalTypes1.errors.txt    | 118 ++++++++++--------
 .../baselines/reference/conditionalTypes1.js  |   4 +-
 .../reference/conditionalTypes1.symbols       |   6 +-
 .../reference/conditionalTypes1.types         |   2 +-
 .../reference/conditionalTypes2.errors.txt    |   6 +-
 .../baselines/reference/deeplyNestedCheck.js  |   2 +-
 .../reference/deeplyNestedCheck.symbols       |   5 +-
 .../reference/deeplyNestedCheck.types         |   5 +-
 .../reference/deferredLookupTypeResolution.js |   4 +-
 .../deferredLookupTypeResolution.symbols      |   5 +-
 .../deferredLookupTypeResolution.types        |  13 +-
 .../deferredLookupTypeResolution2.errors.txt  |  10 +-
 .../deferredLookupTypeResolution2.js          |   4 +-
 .../deferredLookupTypeResolution2.symbols     |   7 +-
 .../deferredLookupTypeResolution2.types       |  31 ++---
 .../reference/for-inStatements.errors.txt     |   8 +-
 .../for-inStatementsInvalid.errors.txt        |   8 +-
 .../baselines/reference/forInStatement3.types |   2 +-
 .../reference/implicitAnyInCatch.types        |   2 +-
 .../reference/inOperatorWithGeneric.types     |   2 +-
 .../indexedAccessRetainsIndexSignature.js     |   2 +-
 ...indexedAccessRetainsIndexSignature.symbols |   6 +-
 .../indexedAccessRetainsIndexSignature.types  |   2 +-
 .../reference/indexerConstraints2.types       |   6 +-
 .../reference/inferTypes1.errors.txt          |   6 +-
 .../isomorphicMappedTypeInference.types       |  44 +++----
 tests/baselines/reference/keyofAndForIn.types |  24 ++--
 .../reference/keyofAndIndexedAccess.js        |   4 +-
 .../reference/keyofAndIndexedAccess.symbols   |  17 +--
 .../reference/keyofAndIndexedAccess.types     |  43 +++----
 .../keyofAndIndexedAccessErrors.errors.txt    |  36 +++---
 .../reference/keyofAndIndexedAccessErrors.js  |   2 +-
 .../keyofAndIndexedAccessErrors.symbols       |  27 ++--
 .../keyofAndIndexedAccessErrors.types         |  35 +++---
 ...ndConstraintTypeChecksCorrectly.errors.txt |  29 -----
 .../reference/mappedTypeErrors.errors.txt     |  23 ++--
 .../reference/mappedTypeErrors.types          |  24 ++--
 .../mappedTypeRelationships.errors.txt        |  24 ++--
 .../reference/mappedTypeWithAny.types         |   2 +-
 tests/baselines/reference/mappedTypes4.types  |  16 +--
 .../reference/neverUnionIntersection.types    |   2 +-
 .../recursiveTypeRelations.errors.txt         |   2 +-
 .../reference/recursiveTypeRelations.js       |   2 +-
 .../reference/recursiveTypeRelations.symbols  |   2 +-
 .../reference/recursiveTypeRelations.types    |   2 +-
 .../reference/typeGuardsTypeParameters.types  |  12 +-
 46 files changed, 330 insertions(+), 308 deletions(-)
 delete mode 100644 tests/baselines/reference/lateBoundConstraintTypeChecksCorrectly.errors.txt

diff --git a/tests/baselines/reference/conditionalTypes1.errors.txt b/tests/baselines/reference/conditionalTypes1.errors.txt
index 5d1f72c14a0..acb72d2cb56 100644
--- a/tests/baselines/reference/conditionalTypes1.errors.txt
+++ b/tests/baselines/reference/conditionalTypes1.errors.txt
@@ -20,32 +20,39 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(106,5): error TS2
   Type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
     Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
       Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
-        Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
-          Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-            Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-              Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-                Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-                  Type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+        Type 'string | number | symbol' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
+          Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
+            Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+              Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+                Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+                  Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
                     Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-                      Type 'keyof T' is not assignable to type 'never'.
-                        Type 'string' is not assignable to type 'never'.
+                      Type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+                        Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+                          Type 'keyof T' is not assignable to type 'never'.
+                            Type 'string | number | symbol' is not assignable to type 'never'.
+                              Type 'string' is not assignable to type 'never'.
 tests/cases/conformance/types/conditional/conditionalTypes1.ts(108,5): error TS2322: Type 'Pick<T, { [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]>' is not assignable to type 'Pick<T, { [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]>'.
   Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
     Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
       Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
-        Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
-          Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-            Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-              Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-                Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-                  Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+        Type 'string | number | symbol' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
+          Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
+            Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+              Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+                Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+                  Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
                     Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-                      Type 'keyof T' is not assignable to type 'never'.
+                      Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+                        Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+                          Type 'keyof T' is not assignable to type 'never'.
 tests/cases/conformance/types/conditional/conditionalTypes1.ts(114,5): error TS2322: Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
-  Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
-    Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-      Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-        Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+  Type 'string | number | symbol' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
+    Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
+      Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+        Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+          Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+            Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
 tests/cases/conformance/types/conditional/conditionalTypes1.ts(115,5): error TS2322: Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
   Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
     Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
@@ -53,12 +60,15 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(115,5): error TS2
         Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
           Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
             Type 'keyof T' is not assignable to type 'never'.
-              Type 'string' is not assignable to type 'never'.
+              Type 'string | number | symbol' is not assignable to type 'never'.
+                Type 'string' is not assignable to type 'never'.
 tests/cases/conformance/types/conditional/conditionalTypes1.ts(116,5): error TS2322: Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
-  Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
-    Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-      Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-        Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+  Type 'string | number | symbol' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
+    Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
+      Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+        Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+          Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+            Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
 tests/cases/conformance/types/conditional/conditionalTypes1.ts(117,5): error TS2322: Type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
   Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
     Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
@@ -221,15 +231,18 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(288,43): error TS
 !!! error TS2322:   Type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
 !!! error TS2322:     Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
 !!! error TS2322:       Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
-!!! error TS2322:         Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
-!!! error TS2322:           Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-!!! error TS2322:             Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-!!! error TS2322:               Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-!!! error TS2322:                 Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-!!! error TS2322:                   Type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:         Type 'string | number | symbol' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
+!!! error TS2322:           Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
+!!! error TS2322:             Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:               Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:                 Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:                   Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
 !!! error TS2322:                     Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-!!! error TS2322:                       Type 'keyof T' is not assignable to type 'never'.
-!!! error TS2322:                         Type 'string' is not assignable to type 'never'.
+!!! error TS2322:                       Type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:                         Type 'T[keyof T] extends Function ? keyof T : never' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:                           Type 'keyof T' is not assignable to type 'never'.
+!!! error TS2322:                             Type 'string | number | symbol' is not assignable to type 'never'.
+!!! error TS2322:                               Type 'string' is not assignable to type 'never'.
         z = x;
         z = y;  // Error
         ~
@@ -237,14 +250,16 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(288,43): error TS
 !!! error TS2322:   Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
 !!! error TS2322:     Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
 !!! error TS2322:       Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
-!!! error TS2322:         Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
-!!! error TS2322:           Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-!!! error TS2322:             Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-!!! error TS2322:               Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-!!! error TS2322:                 Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-!!! error TS2322:                   Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:         Type 'string | number | symbol' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
+!!! error TS2322:           Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
+!!! error TS2322:             Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:               Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:                 Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:                   Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
 !!! error TS2322:                     Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-!!! error TS2322:                       Type 'keyof T' is not assignable to type 'never'.
+!!! error TS2322:                       Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:                         Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:                           Type 'keyof T' is not assignable to type 'never'.
     }
     
     function f8<T>(x: keyof T, y: FunctionPropertyNames<T>, z: NonFunctionPropertyNames<T>) {
@@ -253,10 +268,12 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(288,43): error TS
         y = x;  // Error
         ~
 !!! error TS2322: Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
-!!! error TS2322:   Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
-!!! error TS2322:     Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-!!! error TS2322:       Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
-!!! error TS2322:         Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:   Type 'string | number | symbol' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
+!!! error TS2322:     Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
+!!! error TS2322:       Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:         Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:           Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
+!!! error TS2322:             Type 'string' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
         y = z;  // Error
         ~
 !!! error TS2322: Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]'.
@@ -266,14 +283,17 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(288,43): error TS
 !!! error TS2322:         Type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
 !!! error TS2322:           Type 'T[keyof T] extends Function ? never : keyof T' is not assignable to type 'T[keyof T] extends Function ? keyof T : never'.
 !!! error TS2322:             Type 'keyof T' is not assignable to type 'never'.
-!!! error TS2322:               Type 'string' is not assignable to type 'never'.
+!!! error TS2322:               Type 'string | number | symbol' is not assignable to type 'never'.
+!!! error TS2322:                 Type 'string' is not assignable to type 'never'.
         z = x;  // Error
         ~
 !!! error TS2322: Type 'keyof T' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
-!!! error TS2322:   Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
-!!! error TS2322:     Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-!!! error TS2322:       Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
-!!! error TS2322:         Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:   Type 'string | number | symbol' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
+!!! error TS2322:     Type 'string' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
+!!! error TS2322:       Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:         Type 'keyof T' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:           Type 'string | number | symbol' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
+!!! error TS2322:             Type 'string' is not assignable to type 'T[keyof T] extends Function ? never : keyof T'.
         z = y;  // Error
         ~
 !!! error TS2322: Type '{ [K in keyof T]: T[K] extends Function ? K : never; }[keyof T]' is not assignable to type '{ [K in keyof T]: T[K] extends Function ? never : K; }[keyof T]'.
@@ -491,7 +511,7 @@ tests/cases/conformance/types/conditional/conditionalTypes1.ts(288,43): error TS
     
     // Repro from #21862
     
-    type OldDiff<T extends string, U extends string> = (
+    type OldDiff<T extends keyof any, U extends keyof any> = (
         & { [P in T]: P; }
         & { [P in U]: never; }
         & { [x: string]: never; }
diff --git a/tests/baselines/reference/conditionalTypes1.js b/tests/baselines/reference/conditionalTypes1.js
index 3e5e385625b..552a80d58a5 100644
--- a/tests/baselines/reference/conditionalTypes1.js
+++ b/tests/baselines/reference/conditionalTypes1.js
@@ -301,7 +301,7 @@ function f50() {
 
 // Repro from #21862
 
-type OldDiff<T extends string, U extends string> = (
+type OldDiff<T extends keyof any, U extends keyof any> = (
     & { [P in T]: P; }
     & { [P in U]: never; }
     & { [x: string]: never; }
@@ -656,7 +656,7 @@ declare type T95<T> = T extends string ? boolean : number;
 declare const f44: <U>(value: T94<U>) => T95<U>;
 declare const f45: <U>(value: T95<U>) => T94<U>;
 declare function f50(): void;
-declare type OldDiff<T extends string, U extends string> = ({
+declare type OldDiff<T extends keyof any, U extends keyof any> = ({
     [P in T]: P;
 } & {
     [P in U]: never;
diff --git a/tests/baselines/reference/conditionalTypes1.symbols b/tests/baselines/reference/conditionalTypes1.symbols
index fb0ce83e0a7..5f6bb75514d 100644
--- a/tests/baselines/reference/conditionalTypes1.symbols
+++ b/tests/baselines/reference/conditionalTypes1.symbols
@@ -1186,10 +1186,10 @@ function f50() {
 
 // Repro from #21862
 
-type OldDiff<T extends string, U extends string> = (
+type OldDiff<T extends keyof any, U extends keyof any> = (
 >OldDiff : Symbol(OldDiff, Decl(conditionalTypes1.ts, 298, 1))
 >T : Symbol(T, Decl(conditionalTypes1.ts, 302, 13))
->U : Symbol(U, Decl(conditionalTypes1.ts, 302, 30))
+>U : Symbol(U, Decl(conditionalTypes1.ts, 302, 33))
 
     & { [P in T]: P; }
 >P : Symbol(P, Decl(conditionalTypes1.ts, 303, 9))
@@ -1198,7 +1198,7 @@ type OldDiff<T extends string, U extends string> = (
 
     & { [P in U]: never; }
 >P : Symbol(P, Decl(conditionalTypes1.ts, 304, 9))
->U : Symbol(U, Decl(conditionalTypes1.ts, 302, 30))
+>U : Symbol(U, Decl(conditionalTypes1.ts, 302, 33))
 
     & { [x: string]: never; }
 >x : Symbol(x, Decl(conditionalTypes1.ts, 305, 9))
diff --git a/tests/baselines/reference/conditionalTypes1.types b/tests/baselines/reference/conditionalTypes1.types
index 2ba376781a5..90d2703d034 100644
--- a/tests/baselines/reference/conditionalTypes1.types
+++ b/tests/baselines/reference/conditionalTypes1.types
@@ -1343,7 +1343,7 @@ function f50() {
 
 // Repro from #21862
 
-type OldDiff<T extends string, U extends string> = (
+type OldDiff<T extends keyof any, U extends keyof any> = (
 >OldDiff : ({ [P in T]: P; } & { [P in U]: never; } & { [x: string]: never; })[T]
 >T : T
 >U : U
diff --git a/tests/baselines/reference/conditionalTypes2.errors.txt b/tests/baselines/reference/conditionalTypes2.errors.txt
index 41adb72f62d..127e94196f6 100644
--- a/tests/baselines/reference/conditionalTypes2.errors.txt
+++ b/tests/baselines/reference/conditionalTypes2.errors.txt
@@ -6,7 +6,8 @@ tests/cases/conformance/types/conditional/conditionalTypes2.ts(24,5): error TS23
   Types of property 'foo' are incompatible.
     Type 'B extends string ? keyof B : B' is not assignable to type 'A extends string ? keyof A : A'.
       Type 'keyof B' is not assignable to type 'keyof A'.
-        Type 'string' is not assignable to type 'keyof A'.
+        Type 'string | number | symbol' is not assignable to type 'keyof A'.
+          Type 'string' is not assignable to type 'keyof A'.
 tests/cases/conformance/types/conditional/conditionalTypes2.ts(25,5): error TS2322: Type 'Invariant<A>' is not assignable to type 'Invariant<B>'.
   Types of property 'foo' are incompatible.
     Type 'A extends string ? keyof A : A' is not assignable to type 'B extends string ? keyof B : B'.
@@ -61,7 +62,8 @@ tests/cases/conformance/types/conditional/conditionalTypes2.ts(75,12): error TS2
 !!! error TS2322:   Types of property 'foo' are incompatible.
 !!! error TS2322:     Type 'B extends string ? keyof B : B' is not assignable to type 'A extends string ? keyof A : A'.
 !!! error TS2322:       Type 'keyof B' is not assignable to type 'keyof A'.
-!!! error TS2322:         Type 'string' is not assignable to type 'keyof A'.
+!!! error TS2322:         Type 'string | number | symbol' is not assignable to type 'keyof A'.
+!!! error TS2322:           Type 'string' is not assignable to type 'keyof A'.
         b = a;  // Error
         ~
 !!! error TS2322: Type 'Invariant<A>' is not assignable to type 'Invariant<B>'.
diff --git a/tests/baselines/reference/deeplyNestedCheck.js b/tests/baselines/reference/deeplyNestedCheck.js
index 466ae94f12d..ccd234e2580 100644
--- a/tests/baselines/reference/deeplyNestedCheck.js
+++ b/tests/baselines/reference/deeplyNestedCheck.js
@@ -6,7 +6,7 @@ interface DataSnapshot<X = {}> {
 }
 
 interface Snapshot<T> extends DataSnapshot {
-  child<U extends keyof T>(path: U): Snapshot<T[U]>;
+  child<U extends Extract<keyof T, string>>(path: U): Snapshot<T[U]>;
 }
 
 
diff --git a/tests/baselines/reference/deeplyNestedCheck.symbols b/tests/baselines/reference/deeplyNestedCheck.symbols
index a8b5af60880..80c531cd6d0 100644
--- a/tests/baselines/reference/deeplyNestedCheck.symbols
+++ b/tests/baselines/reference/deeplyNestedCheck.symbols
@@ -16,11 +16,12 @@ interface Snapshot<T> extends DataSnapshot {
 >T : Symbol(T, Decl(deeplyNestedCheck.ts, 6, 19))
 >DataSnapshot : Symbol(DataSnapshot, Decl(deeplyNestedCheck.ts, 0, 0))
 
-  child<U extends keyof T>(path: U): Snapshot<T[U]>;
+  child<U extends Extract<keyof T, string>>(path: U): Snapshot<T[U]>;
 >child : Symbol(Snapshot.child, Decl(deeplyNestedCheck.ts, 6, 44))
 >U : Symbol(U, Decl(deeplyNestedCheck.ts, 7, 8))
+>Extract : Symbol(Extract, Decl(lib.d.ts, --, --))
 >T : Symbol(T, Decl(deeplyNestedCheck.ts, 6, 19))
->path : Symbol(path, Decl(deeplyNestedCheck.ts, 7, 27))
+>path : Symbol(path, Decl(deeplyNestedCheck.ts, 7, 44))
 >U : Symbol(U, Decl(deeplyNestedCheck.ts, 7, 8))
 >Snapshot : Symbol(Snapshot, Decl(deeplyNestedCheck.ts, 4, 1))
 >T : Symbol(T, Decl(deeplyNestedCheck.ts, 6, 19))
diff --git a/tests/baselines/reference/deeplyNestedCheck.types b/tests/baselines/reference/deeplyNestedCheck.types
index e500fc75ed1..dc8550bc2cb 100644
--- a/tests/baselines/reference/deeplyNestedCheck.types
+++ b/tests/baselines/reference/deeplyNestedCheck.types
@@ -16,9 +16,10 @@ interface Snapshot<T> extends DataSnapshot {
 >T : T
 >DataSnapshot : DataSnapshot<X>
 
-  child<U extends keyof T>(path: U): Snapshot<T[U]>;
->child : <U extends keyof T>(path: U) => Snapshot<T[U]>
+  child<U extends Extract<keyof T, string>>(path: U): Snapshot<T[U]>;
+>child : <U extends Extract<keyof T, string>>(path: U) => Snapshot<T[U]>
 >U : U
+>Extract : Extract<T, U>
 >T : T
 >path : U
 >U : U
diff --git a/tests/baselines/reference/deferredLookupTypeResolution.js b/tests/baselines/reference/deferredLookupTypeResolution.js
index e5baa6891e8..126f9d1345a 100644
--- a/tests/baselines/reference/deferredLookupTypeResolution.js
+++ b/tests/baselines/reference/deferredLookupTypeResolution.js
@@ -6,7 +6,7 @@ type StringContains<S extends string, L extends string> = (
     { [key: string]: 'false' }
   )[L]
 
-type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>
+type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>
 
 type First<T> = ObjectHasKey<T, '0'>;  // Should be deferred
 
@@ -43,7 +43,7 @@ declare type StringContains<S extends string, L extends string> = ({
 } & {
     [key: string]: 'false';
 })[L];
-declare type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>;
+declare type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>;
 declare type First<T> = ObjectHasKey<T, '0'>;
 declare type T1 = ObjectHasKey<{
     a: string;
diff --git a/tests/baselines/reference/deferredLookupTypeResolution.symbols b/tests/baselines/reference/deferredLookupTypeResolution.symbols
index 022dc3cc2f4..29906ac6ae1 100644
--- a/tests/baselines/reference/deferredLookupTypeResolution.symbols
+++ b/tests/baselines/reference/deferredLookupTypeResolution.symbols
@@ -16,16 +16,17 @@ type StringContains<S extends string, L extends string> = (
   )[L]
 >L : Symbol(L, Decl(deferredLookupTypeResolution.ts, 2, 37))
 
-type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>
+type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>
 >ObjectHasKey : Symbol(ObjectHasKey, Decl(deferredLookupTypeResolution.ts, 5, 6))
 >O : Symbol(O, Decl(deferredLookupTypeResolution.ts, 7, 18))
 >L : Symbol(L, Decl(deferredLookupTypeResolution.ts, 7, 20))
 >StringContains : Symbol(StringContains, Decl(deferredLookupTypeResolution.ts, 0, 0))
+>Extract : Symbol(Extract, Decl(lib.d.ts, --, --))
 >O : Symbol(O, Decl(deferredLookupTypeResolution.ts, 7, 18))
 >L : Symbol(L, Decl(deferredLookupTypeResolution.ts, 7, 20))
 
 type First<T> = ObjectHasKey<T, '0'>;  // Should be deferred
->First : Symbol(First, Decl(deferredLookupTypeResolution.ts, 7, 67))
+>First : Symbol(First, Decl(deferredLookupTypeResolution.ts, 7, 84))
 >T : Symbol(T, Decl(deferredLookupTypeResolution.ts, 9, 11))
 >ObjectHasKey : Symbol(ObjectHasKey, Decl(deferredLookupTypeResolution.ts, 5, 6))
 >T : Symbol(T, Decl(deferredLookupTypeResolution.ts, 9, 11))
diff --git a/tests/baselines/reference/deferredLookupTypeResolution.types b/tests/baselines/reference/deferredLookupTypeResolution.types
index cd123a6019e..4826b03329a 100644
--- a/tests/baselines/reference/deferredLookupTypeResolution.types
+++ b/tests/baselines/reference/deferredLookupTypeResolution.types
@@ -16,28 +16,29 @@ type StringContains<S extends string, L extends string> = (
   )[L]
 >L : L
 
-type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 >O : O
 >L : L
 >StringContains : ({ [K in S]: "true"; } & { [key: string]: "false"; })[L]
+>Extract : Extract<T, U>
 >O : O
 >L : L
 
 type First<T> = ObjectHasKey<T, '0'>;  // Should be deferred
->First : ({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["0"]
+>First : ({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["0"]
 >T : T
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 >T : T
 
 type T1 = ObjectHasKey<{ a: string }, 'a'>;  // 'true'
 >T1 : "true"
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 >a : string
 
 type T2 = ObjectHasKey<{ a: string }, 'b'>;  // 'false'
 >T2 : "false"
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 >a : string
 
 // Verify that mapped type isn't eagerly resolved in type-to-string operation
diff --git a/tests/baselines/reference/deferredLookupTypeResolution2.errors.txt b/tests/baselines/reference/deferredLookupTypeResolution2.errors.txt
index 6d1d579c0ad..88bcd2c4340 100644
--- a/tests/baselines/reference/deferredLookupTypeResolution2.errors.txt
+++ b/tests/baselines/reference/deferredLookupTypeResolution2.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/compiler/deferredLookupTypeResolution2.ts(14,13): error TS2536: Type '({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]' cannot be used to index type '{ true: "true"; }'.
-tests/cases/compiler/deferredLookupTypeResolution2.ts(19,21): error TS2536: Type '({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]]' cannot be used to index type '{ true: "true"; }'.
+tests/cases/compiler/deferredLookupTypeResolution2.ts(14,13): error TS2536: Type '({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]' cannot be used to index type '{ true: "true"; }'.
+tests/cases/compiler/deferredLookupTypeResolution2.ts(19,21): error TS2536: Type '({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]]' cannot be used to index type '{ true: "true"; }'.
 
 
 ==== tests/cases/compiler/deferredLookupTypeResolution2.ts (2 errors) ====
@@ -7,7 +7,7 @@ tests/cases/compiler/deferredLookupTypeResolution2.ts(19,21): error TS2536: Type
     
     type StringContains<S extends string, L extends string> = ({ [K in S]: 'true' } & { [key: string]: 'false'})[L];
     
-    type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>;
+    type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>;
     
     type A<T> = ObjectHasKey<T, '0'>;
     
@@ -18,14 +18,14 @@ tests/cases/compiler/deferredLookupTypeResolution2.ts(19,21): error TS2536: Type
     // Error, "false" not handled
     type E<T> = { true: 'true' }[ObjectHasKey<T, '1'>];
                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2536: Type '({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]' cannot be used to index type '{ true: "true"; }'.
+!!! error TS2536: Type '({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]' cannot be used to index type '{ true: "true"; }'.
     
     type Juxtapose<T> = ({ true: 'otherwise' } & { [k: string]: 'true' })[ObjectHasKey<T, '1'>];
     
     // Error, "otherwise" is missing
     type DeepError<T> = { true: 'true' }[Juxtapose<T>];
                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2536: Type '({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]]' cannot be used to index type '{ true: "true"; }'.
+!!! error TS2536: Type '({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]]' cannot be used to index type '{ true: "true"; }'.
     
     type DeepOK<T> = { true: 'true', otherwise: 'false' }[Juxtapose<T>];
     
\ No newline at end of file
diff --git a/tests/baselines/reference/deferredLookupTypeResolution2.js b/tests/baselines/reference/deferredLookupTypeResolution2.js
index 97289f47f9c..3d40dcb4bbf 100644
--- a/tests/baselines/reference/deferredLookupTypeResolution2.js
+++ b/tests/baselines/reference/deferredLookupTypeResolution2.js
@@ -3,7 +3,7 @@
 
 type StringContains<S extends string, L extends string> = ({ [K in S]: 'true' } & { [key: string]: 'false'})[L];
 
-type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>;
+type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>;
 
 type A<T> = ObjectHasKey<T, '0'>;
 
@@ -33,7 +33,7 @@ declare type StringContains<S extends string, L extends string> = ({
 } & {
     [key: string]: 'false';
 })[L];
-declare type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>;
+declare type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>;
 declare type A<T> = ObjectHasKey<T, '0'>;
 declare type B = ObjectHasKey<[string, number], '1'>;
 declare type C = ObjectHasKey<[string, number], '2'>;
diff --git a/tests/baselines/reference/deferredLookupTypeResolution2.symbols b/tests/baselines/reference/deferredLookupTypeResolution2.symbols
index ca55b3e407e..41064fae533 100644
--- a/tests/baselines/reference/deferredLookupTypeResolution2.symbols
+++ b/tests/baselines/reference/deferredLookupTypeResolution2.symbols
@@ -10,16 +10,17 @@ type StringContains<S extends string, L extends string> = ({ [K in S]: 'true' }
 >key : Symbol(key, Decl(deferredLookupTypeResolution2.ts, 2, 85))
 >L : Symbol(L, Decl(deferredLookupTypeResolution2.ts, 2, 37))
 
-type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>;
+type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>;
 >ObjectHasKey : Symbol(ObjectHasKey, Decl(deferredLookupTypeResolution2.ts, 2, 112))
 >O : Symbol(O, Decl(deferredLookupTypeResolution2.ts, 4, 18))
 >L : Symbol(L, Decl(deferredLookupTypeResolution2.ts, 4, 20))
 >StringContains : Symbol(StringContains, Decl(deferredLookupTypeResolution2.ts, 0, 0))
+>Extract : Symbol(Extract, Decl(lib.d.ts, --, --))
 >O : Symbol(O, Decl(deferredLookupTypeResolution2.ts, 4, 18))
 >L : Symbol(L, Decl(deferredLookupTypeResolution2.ts, 4, 20))
 
 type A<T> = ObjectHasKey<T, '0'>;
->A : Symbol(A, Decl(deferredLookupTypeResolution2.ts, 4, 68))
+>A : Symbol(A, Decl(deferredLookupTypeResolution2.ts, 4, 85))
 >T : Symbol(T, Decl(deferredLookupTypeResolution2.ts, 6, 7))
 >ObjectHasKey : Symbol(ObjectHasKey, Decl(deferredLookupTypeResolution2.ts, 2, 112))
 >T : Symbol(T, Decl(deferredLookupTypeResolution2.ts, 6, 7))
@@ -34,7 +35,7 @@ type C = ObjectHasKey<[string, number], '2'>;  // "false"
 
 type D = A<[string]>;  // "true"
 >D : Symbol(D, Decl(deferredLookupTypeResolution2.ts, 9, 45))
->A : Symbol(A, Decl(deferredLookupTypeResolution2.ts, 4, 68))
+>A : Symbol(A, Decl(deferredLookupTypeResolution2.ts, 4, 85))
 
 // Error, "false" not handled
 type E<T> = { true: 'true' }[ObjectHasKey<T, '1'>];
diff --git a/tests/baselines/reference/deferredLookupTypeResolution2.types b/tests/baselines/reference/deferredLookupTypeResolution2.types
index 76354731097..88994722a2e 100644
--- a/tests/baselines/reference/deferredLookupTypeResolution2.types
+++ b/tests/baselines/reference/deferredLookupTypeResolution2.types
@@ -10,61 +10,62 @@ type StringContains<S extends string, L extends string> = ({ [K in S]: 'true' }
 >key : string
 >L : L
 
-type ObjectHasKey<O, L extends string> = StringContains<keyof O, L>;
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+type ObjectHasKey<O, L extends string> = StringContains<Extract<keyof O, string>, L>;
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 >O : O
 >L : L
 >StringContains : ({ [K in S]: "true"; } & { [key: string]: "false"; })[L]
+>Extract : Extract<T, U>
 >O : O
 >L : L
 
 type A<T> = ObjectHasKey<T, '0'>;
->A : ({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["0"]
+>A : ({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["0"]
 >T : T
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 >T : T
 
 type B = ObjectHasKey<[string, number], '1'>;  // "true"
 >B : "true"
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 
 type C = ObjectHasKey<[string, number], '2'>;  // "false"
 >C : "false"
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 
 type D = A<[string]>;  // "true"
 >D : "true"
->A : ({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["0"]
+>A : ({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["0"]
 
 // Error, "false" not handled
 type E<T> = { true: 'true' }[ObjectHasKey<T, '1'>];
->E : { true: "true"; }[({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]]
+>E : { true: "true"; }[({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]]
 >T : T
 >true : "true"
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 >T : T
 
 type Juxtapose<T> = ({ true: 'otherwise' } & { [k: string]: 'true' })[ObjectHasKey<T, '1'>];
->Juxtapose : ({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]]
+>Juxtapose : ({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]]
 >T : T
 >true : "otherwise"
 >k : string
->ObjectHasKey : ({ [K in keyof O]: "true"; } & { [key: string]: "false"; })[L]
+>ObjectHasKey : ({ [K in Extract<keyof O, string>]: "true"; } & { [key: string]: "false"; })[L]
 >T : T
 
 // Error, "otherwise" is missing
 type DeepError<T> = { true: 'true' }[Juxtapose<T>];
->DeepError : { true: "true"; }[({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]]]
+>DeepError : { true: "true"; }[({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]]]
 >T : T
 >true : "true"
->Juxtapose : ({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]]
+>Juxtapose : ({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]]
 >T : T
 
 type DeepOK<T> = { true: 'true', otherwise: 'false' }[Juxtapose<T>];
->DeepOK : { true: "true"; otherwise: "false"; }[({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]]]
+>DeepOK : { true: "true"; otherwise: "false"; }[({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]]]
 >T : T
 >true : "true"
 >otherwise : "false"
->Juxtapose : ({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in keyof T]: "true"; } & { [key: string]: "false"; })["1"]]
+>Juxtapose : ({ true: "otherwise"; } & { [k: string]: "true"; })[({ [K in Extract<keyof T, string>]: "true"; } & { [key: string]: "false"; })["1"]]
 >T : T
 
diff --git a/tests/baselines/reference/for-inStatements.errors.txt b/tests/baselines/reference/for-inStatements.errors.txt
index 2ae4cdb79f0..50f31d669cd 100644
--- a/tests/baselines/reference/for-inStatements.errors.txt
+++ b/tests/baselines/reference/for-inStatements.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/conformance/statements/for-inStatements/for-inStatements.ts(33,18): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'keyof this'.
-tests/cases/conformance/statements/for-inStatements/for-inStatements.ts(50,18): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'keyof this'.
+tests/cases/conformance/statements/for-inStatements/for-inStatements.ts(33,18): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'Extract<keyof this, string>'.
+tests/cases/conformance/statements/for-inStatements/for-inStatements.ts(50,18): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'Extract<keyof this, string>'.
 tests/cases/conformance/statements/for-inStatements/for-inStatements.ts(79,15): error TS2407: The right-hand side of a 'for...in' statement must be of type 'any', an object type or a type parameter, but here has type 'Color.Blue'.
 
 
@@ -38,7 +38,7 @@ tests/cases/conformance/statements/for-inStatements/for-inStatements.ts(79,15):
             for (var x in this.biz) { }
             for (var x in this) { }
                      ~
-!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'keyof this'.
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'Extract<keyof this, string>'.
             return null;
         }
     
@@ -57,7 +57,7 @@ tests/cases/conformance/statements/for-inStatements/for-inStatements.ts(79,15):
             for (var x in this.biz) { }
             for (var x in this) { }
                      ~
-!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'keyof this'.
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'Extract<keyof this, string>'.
     
             for (var x in super.biz) { }
             for (var x in super.biz()) { }
diff --git a/tests/baselines/reference/for-inStatementsInvalid.errors.txt b/tests/baselines/reference/for-inStatementsInvalid.errors.txt
index 3d7dd1c79f3..8e1bb29d083 100644
--- a/tests/baselines/reference/for-inStatementsInvalid.errors.txt
+++ b/tests/baselines/reference/for-inStatementsInvalid.errors.txt
@@ -9,10 +9,10 @@ tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(1
 tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(20,15): error TS2407: The right-hand side of a 'for...in' statement must be of type 'any', an object type or a type parameter, but here has type 'string'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(22,15): error TS2407: The right-hand side of a 'for...in' statement must be of type 'any', an object type or a type parameter, but here has type 'string'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(29,23): error TS2407: The right-hand side of a 'for...in' statement must be of type 'any', an object type or a type parameter, but here has type 'number'.
-tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(31,18): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'keyof this'.
+tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(31,18): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'Extract<keyof this, string>'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(38,23): error TS2407: The right-hand side of a 'for...in' statement must be of type 'any', an object type or a type parameter, but here has type 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(46,23): error TS2407: The right-hand side of a 'for...in' statement must be of type 'any', an object type or a type parameter, but here has type 'number'.
-tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(48,18): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'keyof this'.
+tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(48,18): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'Extract<keyof this, string>'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(51,23): error TS2407: The right-hand side of a 'for...in' statement must be of type 'any', an object type or a type parameter, but here has type 'number'.
 tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(62,15): error TS2407: The right-hand side of a 'for...in' statement must be of type 'any', an object type or a type parameter, but here has type 'number'.
 
@@ -72,7 +72,7 @@ tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(6
             for (var x in this.biz) { }
             for (var x in this) { }
                      ~
-!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'keyof this'.
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'Extract<keyof this, string>'.
             return null;
         }
     
@@ -95,7 +95,7 @@ tests/cases/conformance/statements/for-inStatements/for-inStatementsInvalid.ts(6
             for (var x in this.biz) { }
             for (var x in this) { }
                      ~
-!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'keyof this'.
+!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'string', but here has type 'Extract<keyof this, string>'.
     
             for (var x in super.biz) { }
             for (var x in super.biz()) { }
diff --git a/tests/baselines/reference/forInStatement3.types b/tests/baselines/reference/forInStatement3.types
index 09e6cf3ad96..9fe63651f55 100644
--- a/tests/baselines/reference/forInStatement3.types
+++ b/tests/baselines/reference/forInStatement3.types
@@ -8,7 +8,7 @@ function F<T>() {
 >T : T
 
   for (var a in expr) {
->a : keyof T
+>a : Extract<keyof T, string>
 >expr : T
   }
 }
diff --git a/tests/baselines/reference/implicitAnyInCatch.types b/tests/baselines/reference/implicitAnyInCatch.types
index 93cce09928e..6f70165407f 100644
--- a/tests/baselines/reference/implicitAnyInCatch.types
+++ b/tests/baselines/reference/implicitAnyInCatch.types
@@ -22,7 +22,7 @@ class C {
 >temp : () => void
 
         for (var x in this) {
->x : keyof this
+>x : Extract<keyof this, string>
 >this : this
         }
     }
diff --git a/tests/baselines/reference/inOperatorWithGeneric.types b/tests/baselines/reference/inOperatorWithGeneric.types
index eba9bf1419b..dd373d8e075 100644
--- a/tests/baselines/reference/inOperatorWithGeneric.types
+++ b/tests/baselines/reference/inOperatorWithGeneric.types
@@ -9,7 +9,7 @@ class C<T> {
 >T : T
 
         for (var p in x) {
->p : keyof T
+>p : Extract<keyof T, string>
 >x : T
         }
     }
diff --git a/tests/baselines/reference/indexedAccessRetainsIndexSignature.js b/tests/baselines/reference/indexedAccessRetainsIndexSignature.js
index 1b77b95527b..92952515779 100644
--- a/tests/baselines/reference/indexedAccessRetainsIndexSignature.js
+++ b/tests/baselines/reference/indexedAccessRetainsIndexSignature.js
@@ -1,5 +1,5 @@
 //// [indexedAccessRetainsIndexSignature.ts]
-type Diff<T extends string, U extends string> =
+type Diff<T extends keyof any, U extends keyof any> =
     ({ [P in T]: P } & { [P in U]: never } & { [x: string]: never })[T]
 type Omit<U, K extends keyof U> = Pick<U, Diff<keyof U, K>>
 type Omit1<U, K extends keyof U> = Pick<U, Diff<keyof U, K>>;
diff --git a/tests/baselines/reference/indexedAccessRetainsIndexSignature.symbols b/tests/baselines/reference/indexedAccessRetainsIndexSignature.symbols
index 9858f6fc162..ad46c367ba6 100644
--- a/tests/baselines/reference/indexedAccessRetainsIndexSignature.symbols
+++ b/tests/baselines/reference/indexedAccessRetainsIndexSignature.symbols
@@ -1,15 +1,15 @@
 === tests/cases/compiler/indexedAccessRetainsIndexSignature.ts ===
-type Diff<T extends string, U extends string> =
+type Diff<T extends keyof any, U extends keyof any> =
 >Diff : Symbol(Diff, Decl(indexedAccessRetainsIndexSignature.ts, 0, 0))
 >T : Symbol(T, Decl(indexedAccessRetainsIndexSignature.ts, 0, 10))
->U : Symbol(U, Decl(indexedAccessRetainsIndexSignature.ts, 0, 27))
+>U : Symbol(U, Decl(indexedAccessRetainsIndexSignature.ts, 0, 30))
 
     ({ [P in T]: P } & { [P in U]: never } & { [x: string]: never })[T]
 >P : Symbol(P, Decl(indexedAccessRetainsIndexSignature.ts, 1, 8))
 >T : Symbol(T, Decl(indexedAccessRetainsIndexSignature.ts, 0, 10))
 >P : Symbol(P, Decl(indexedAccessRetainsIndexSignature.ts, 1, 8))
 >P : Symbol(P, Decl(indexedAccessRetainsIndexSignature.ts, 1, 26))
->U : Symbol(U, Decl(indexedAccessRetainsIndexSignature.ts, 0, 27))
+>U : Symbol(U, Decl(indexedAccessRetainsIndexSignature.ts, 0, 30))
 >x : Symbol(x, Decl(indexedAccessRetainsIndexSignature.ts, 1, 48))
 >T : Symbol(T, Decl(indexedAccessRetainsIndexSignature.ts, 0, 10))
 
diff --git a/tests/baselines/reference/indexedAccessRetainsIndexSignature.types b/tests/baselines/reference/indexedAccessRetainsIndexSignature.types
index 8dcbe9bf218..5334cf891df 100644
--- a/tests/baselines/reference/indexedAccessRetainsIndexSignature.types
+++ b/tests/baselines/reference/indexedAccessRetainsIndexSignature.types
@@ -1,5 +1,5 @@
 === tests/cases/compiler/indexedAccessRetainsIndexSignature.ts ===
-type Diff<T extends string, U extends string> =
+type Diff<T extends keyof any, U extends keyof any> =
 >Diff : ({ [P in T]: P; } & { [P in U]: never; } & { [x: string]: never; })[T]
 >T : T
 >U : U
diff --git a/tests/baselines/reference/indexerConstraints2.types b/tests/baselines/reference/indexerConstraints2.types
index ec2126f438d..e2db782d788 100644
--- a/tests/baselines/reference/indexerConstraints2.types
+++ b/tests/baselines/reference/indexerConstraints2.types
@@ -125,14 +125,14 @@ interface P {
 }
 
 type NonIndexableUnion2 = string | number;
->NonIndexableUnion2 : string | number
+>NonIndexableUnion2 : NonIndexableUnion2
 
 interface Q {
 >Q : Q
 
     [u: NonIndexableUnion2]: A;
->u : string | number
->NonIndexableUnion2 : string | number
+>u : NonIndexableUnion2
+>NonIndexableUnion2 : NonIndexableUnion2
 >A : A
 }
 
diff --git a/tests/baselines/reference/inferTypes1.errors.txt b/tests/baselines/reference/inferTypes1.errors.txt
index 01907bdc95b..4684b8f5e34 100644
--- a/tests/baselines/reference/inferTypes1.errors.txt
+++ b/tests/baselines/reference/inferTypes1.errors.txt
@@ -17,7 +17,8 @@ tests/cases/conformance/types/conditional/inferTypes1.ts(75,43): error TS2304: C
 tests/cases/conformance/types/conditional/inferTypes1.ts(75,43): error TS4081: Exported type alias 'T62' has or is using private name 'U'.
 tests/cases/conformance/types/conditional/inferTypes1.ts(82,44): error TS2344: Type 'U' does not satisfy the constraint 'string'.
   Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/types/conditional/inferTypes1.ts(144,40): error TS2322: Type 'T' is not assignable to type 'string'.
+tests/cases/conformance/types/conditional/inferTypes1.ts(144,40): error TS2322: Type 'T' is not assignable to type 'string | number | symbol'.
+  Type 'T' is not assignable to type 'symbol'.
 
 
 ==== tests/cases/conformance/types/conditional/inferTypes1.ts (16 errors) ====
@@ -200,7 +201,8 @@ tests/cases/conformance/types/conditional/inferTypes1.ts(144,40): error TS2322:
     type A<T> = T extends string ? { [P in T]: void; } : T;
     type B<T> = string extends T ? { [P in T]: void; } : T;  // Error
                                            ~
-!!! error TS2322: Type 'T' is not assignable to type 'string'.
+!!! error TS2322: Type 'T' is not assignable to type 'string | number | symbol'.
+!!! error TS2322:   Type 'T' is not assignable to type 'symbol'.
     
     // Repro from #22302
     
diff --git a/tests/baselines/reference/isomorphicMappedTypeInference.types b/tests/baselines/reference/isomorphicMappedTypeInference.types
index b24bb071eeb..d0db5608b6f 100644
--- a/tests/baselines/reference/isomorphicMappedTypeInference.types
+++ b/tests/baselines/reference/isomorphicMappedTypeInference.types
@@ -64,19 +64,19 @@ function boxify<T>(obj: T): Boxified<T> {
 >T : T
 
     for (let k in obj) {
->k : keyof T
+>k : Extract<keyof T, string>
 >obj : T
 
         result[k] = box(obj[k]);
->result[k] = box(obj[k]) : Box<T[keyof T]>
->result[k] : Boxified<T>[keyof T]
+>result[k] = box(obj[k]) : Box<T[Extract<keyof T, string>]>
+>result[k] : Boxified<T>[Extract<keyof T, string>]
 >result : Boxified<T>
->k : keyof T
->box(obj[k]) : Box<T[keyof T]>
+>k : Extract<keyof T, string>
+>box(obj[k]) : Box<T[Extract<keyof T, string>]>
 >box : <T>(x: T) => Box<T>
->obj[k] : T[keyof T]
+>obj[k] : T[Extract<keyof T, string>]
 >obj : T
->k : keyof T
+>k : Extract<keyof T, string>
     }
     return result;
 >result : Boxified<T>
@@ -97,19 +97,19 @@ function unboxify<T>(obj: Boxified<T>): T {
 >T : T
 
     for (let k in obj) {
->k : keyof T
+>k : Extract<keyof T, string>
 >obj : Boxified<T>
 
         result[k] = unbox(obj[k]);
->result[k] = unbox(obj[k]) : T[keyof T]
->result[k] : T[keyof T]
+>result[k] = unbox(obj[k]) : T[Extract<keyof T, string>]
+>result[k] : T[Extract<keyof T, string>]
 >result : T
->k : keyof T
->unbox(obj[k]) : T[keyof T]
+>k : Extract<keyof T, string>
+>unbox(obj[k]) : T[Extract<keyof T, string>]
 >unbox : <T>(x: Box<T>) => T
->obj[k] : Boxified<T>[keyof T]
+>obj[k] : Boxified<T>[Extract<keyof T, string>]
 >obj : Boxified<T>
->k : keyof T
+>k : Extract<keyof T, string>
     }
     return result;
 >result : T
@@ -125,19 +125,19 @@ function assignBoxified<T>(obj: Boxified<T>, values: T) {
 >T : T
 
     for (let k in values) {
->k : keyof T
+>k : Extract<keyof T, string>
 >values : T
 
         obj[k].value = values[k];
->obj[k].value = values[k] : T[keyof T]
->obj[k].value : T[keyof T]
->obj[k] : Boxified<T>[keyof T]
+>obj[k].value = values[k] : T[Extract<keyof T, string>]
+>obj[k].value : T[Extract<keyof T, string>]
+>obj[k] : Boxified<T>[Extract<keyof T, string>]
 >obj : Boxified<T>
->k : keyof T
->value : T[keyof T]
->values[k] : T[keyof T]
+>k : Extract<keyof T, string>
+>value : T[Extract<keyof T, string>]
+>values[k] : T[Extract<keyof T, string>]
 >values : T
->k : keyof T
+>k : Extract<keyof T, string>
     }
 }
 
diff --git a/tests/baselines/reference/keyofAndForIn.types b/tests/baselines/reference/keyofAndForIn.types
index c4997c05bfe..9de1b651843 100644
--- a/tests/baselines/reference/keyofAndForIn.types
+++ b/tests/baselines/reference/keyofAndForIn.types
@@ -33,14 +33,14 @@ function f1<K extends string, T>(obj: { [P in K]: T }, k: K) {
 >k1 : K
     }
     for (let k2 in obj) {
->k2 : K
+>k2 : Extract<K, string>
 >obj : { [P in K]: T; }
 
         let x2 = obj[k2];
->x2 : { [P in K]: T; }[K]
->obj[k2] : { [P in K]: T; }[K]
+>x2 : { [P in K]: T; }[Extract<K, string>]
+>obj[k2] : { [P in K]: T; }[Extract<K, string>]
 >obj : { [P in K]: T; }
->k2 : K
+>k2 : Extract<K, string>
     }
 }
 
@@ -76,14 +76,14 @@ function f2<T>(obj: { [P in keyof T]: T[P] }, k: keyof T) {
 >k1 : keyof T
     }
     for (let k2 in obj) {
->k2 : keyof T
+>k2 : Extract<keyof T, string>
 >obj : { [P in keyof T]: T[P]; }
 
         let x2 = obj[k2];
->x2 : { [P in keyof T]: T[P]; }[keyof T]
->obj[k2] : { [P in keyof T]: T[P]; }[keyof T]
+>x2 : { [P in keyof T]: T[P]; }[Extract<keyof T, string>]
+>obj[k2] : { [P in keyof T]: T[P]; }[Extract<keyof T, string>]
 >obj : { [P in keyof T]: T[P]; }
->k2 : keyof T
+>k2 : Extract<keyof T, string>
     }
 }
 
@@ -121,13 +121,13 @@ function f3<T, K extends keyof T>(obj: { [P in K]: T[P] }, k: K) {
 >k1 : K
     }
     for (let k2 in obj) {
->k2 : K
+>k2 : Extract<K, string>
 >obj : { [P in K]: T[P]; }
 
         let x2 = obj[k2];
->x2 : { [P in K]: T[P]; }[K]
->obj[k2] : { [P in K]: T[P]; }[K]
+>x2 : { [P in K]: T[P]; }[Extract<K, string>]
+>obj[k2] : { [P in K]: T[P]; }[Extract<K, string>]
 >obj : { [P in K]: T[P]; }
->k2 : K
+>k2 : Extract<K, string>
     }
 }
diff --git a/tests/baselines/reference/keyofAndIndexedAccess.js b/tests/baselines/reference/keyofAndIndexedAccess.js
index 1ee6bfc218b..70f1c8b856e 100644
--- a/tests/baselines/reference/keyofAndIndexedAccess.js
+++ b/tests/baselines/reference/keyofAndIndexedAccess.js
@@ -554,7 +554,7 @@ class AnotherSampleClass<T> extends SampleClass<T & Foo> {
 new AnotherSampleClass({});
 
 // Positive repro from #17166
-function f3<T, K extends keyof T>(t: T, k: K, tk: T[K]): void {
+function f3<T, K extends Extract<keyof T, string>>(t: T, k: K, tk: T[K]): void {
     for (let key in t) {
         key = k // ok, K ==> keyof T
         t[key] = tk; // ok, T[K] ==> T[keyof T]
@@ -1208,7 +1208,7 @@ declare class AnotherSampleClass<T> extends SampleClass<T & Foo> {
     constructor(props: T);
     brokenMethod(): void;
 }
-declare function f3<T, K extends keyof T>(t: T, k: K, tk: T[K]): void;
+declare function f3<T, K extends Extract<keyof T, string>>(t: T, k: K, tk: T[K]): void;
 declare type Predicates<TaggedRecord> = {
     [T in keyof TaggedRecord]: (variant: TaggedRecord[keyof TaggedRecord]) => variant is TaggedRecord[T];
 };
diff --git a/tests/baselines/reference/keyofAndIndexedAccess.symbols b/tests/baselines/reference/keyofAndIndexedAccess.symbols
index c1a3449991f..1d59deb12b3 100644
--- a/tests/baselines/reference/keyofAndIndexedAccess.symbols
+++ b/tests/baselines/reference/keyofAndIndexedAccess.symbols
@@ -1963,31 +1963,32 @@ new AnotherSampleClass({});
 >AnotherSampleClass : Symbol(AnotherSampleClass, Decl(keyofAndIndexedAccess.ts, 540, 54))
 
 // Positive repro from #17166
-function f3<T, K extends keyof T>(t: T, k: K, tk: T[K]): void {
+function f3<T, K extends Extract<keyof T, string>>(t: T, k: K, tk: T[K]): void {
 >f3 : Symbol(f3, Decl(keyofAndIndexedAccess.ts, 552, 27))
 >T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 555, 12))
 >K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 555, 14))
+>Extract : Symbol(Extract, Decl(lib.d.ts, --, --))
 >T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 555, 12))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 555, 34))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 555, 51))
 >T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 555, 12))
->k : Symbol(k, Decl(keyofAndIndexedAccess.ts, 555, 39))
+>k : Symbol(k, Decl(keyofAndIndexedAccess.ts, 555, 56))
 >K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 555, 14))
->tk : Symbol(tk, Decl(keyofAndIndexedAccess.ts, 555, 45))
+>tk : Symbol(tk, Decl(keyofAndIndexedAccess.ts, 555, 62))
 >T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 555, 12))
 >K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 555, 14))
 
     for (let key in t) {
 >key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 556, 12))
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 555, 34))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 555, 51))
 
         key = k // ok, K ==> keyof T
 >key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 556, 12))
->k : Symbol(k, Decl(keyofAndIndexedAccess.ts, 555, 39))
+>k : Symbol(k, Decl(keyofAndIndexedAccess.ts, 555, 56))
 
         t[key] = tk; // ok, T[K] ==> T[keyof T]
->t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 555, 34))
+>t : Symbol(t, Decl(keyofAndIndexedAccess.ts, 555, 51))
 >key : Symbol(key, Decl(keyofAndIndexedAccess.ts, 556, 12))
->tk : Symbol(tk, Decl(keyofAndIndexedAccess.ts, 555, 45))
+>tk : Symbol(tk, Decl(keyofAndIndexedAccess.ts, 555, 62))
     }
 }
 
diff --git a/tests/baselines/reference/keyofAndIndexedAccess.types b/tests/baselines/reference/keyofAndIndexedAccess.types
index 694abf7d10e..462dde9ca03 100644
--- a/tests/baselines/reference/keyofAndIndexedAccess.types
+++ b/tests/baselines/reference/keyofAndIndexedAccess.types
@@ -59,10 +59,10 @@ const enum E { A, B, C }
 >C : E.C
 
 type K00 = keyof any;  // string
->K00 : string
+>K00 : string | number | symbol
 
 type K01 = keyof string;  // "toString" | "charAt" | ...
->K01 : "length" | "toString" | "concat" | "slice" | "indexOf" | "lastIndexOf" | "charAt" | "charCodeAt" | "localeCompare" | "match" | "replace" | "search" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr" | "valueOf"
+>K01 : number | "length" | "toString" | "concat" | "slice" | "indexOf" | "lastIndexOf" | "charAt" | "charCodeAt" | "localeCompare" | "match" | "replace" | "search" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr" | "valueOf"
 
 type K02 = keyof number;  // "toString" | "toFixed" | "toExponential" | ...
 >K02 : "toString" | "toLocaleString" | "valueOf" | "toFixed" | "toExponential" | "toPrecision"
@@ -88,11 +88,11 @@ type K10 = keyof Shape;  // "name" | "width" | "height" | "visible"
 >Shape : Shape
 
 type K11 = keyof Shape[];  // "length" | "toString" | ...
->K11 : "length" | "toString" | "toLocaleString" | "push" | "pop" | "concat" | "join" | "reverse" | "shift" | "slice" | "sort" | "splice" | "unshift" | "indexOf" | "lastIndexOf" | "every" | "some" | "forEach" | "map" | "filter" | "reduce" | "reduceRight"
+>K11 : number | "length" | "toString" | "toLocaleString" | "push" | "pop" | "concat" | "join" | "reverse" | "shift" | "slice" | "sort" | "splice" | "unshift" | "indexOf" | "lastIndexOf" | "every" | "some" | "forEach" | "map" | "filter" | "reduce" | "reduceRight"
 >Shape : Shape
 
 type K12 = keyof Dictionary<Shape>;  // string
->K12 : string
+>K12 : string | number | symbol
 >Dictionary : Dictionary<T>
 >Shape : Shape
 
@@ -108,7 +108,7 @@ type K15 = keyof E;  // "toString" | "toFixed" | "toExponential" | ...
 >E : E
 
 type K16 = keyof [string, number];  // "0" | "1" | "length" | "toString" | ...
->K16 : "0" | "1" | "length" | "toString" | "toLocaleString" | "push" | "pop" | "concat" | "join" | "reverse" | "shift" | "slice" | "sort" | "splice" | "unshift" | "indexOf" | "lastIndexOf" | "every" | "some" | "forEach" | "map" | "filter" | "reduce" | "reduceRight"
+>K16 : number | "0" | "1" | "length" | "toString" | "toLocaleString" | "push" | "pop" | "concat" | "join" | "reverse" | "shift" | "slice" | "sort" | "splice" | "unshift" | "indexOf" | "lastIndexOf" | "every" | "some" | "forEach" | "map" | "filter" | "reduce" | "reduceRight"
 
 type K17 = keyof (Shape | Item);  // "name"
 >K17 : "name"
@@ -121,7 +121,7 @@ type K18 = keyof (Shape & Item);  // "name" | "width" | "height" | "visible" | "
 >Item : Item
 
 type K19 = keyof NumericallyIndexed<Shape> // never
->K19 : never
+>K19 : number
 >NumericallyIndexed : NumericallyIndexed<T>
 >Shape : Shape
 
@@ -136,7 +136,7 @@ type K20 = KeyOf<Shape>;  // "name" | "width" | "height" | "visible"
 >Shape : Shape
 
 type K21 = KeyOf<Dictionary<Shape>>;  // string
->K21 : string
+>K21 : string | number | symbol
 >KeyOf : keyof T
 >Dictionary : Dictionary<T>
 >Shape : Shape
@@ -825,7 +825,7 @@ function f54<T>(obj: T, key: keyof T) {
 >T : T
 
     for (let s in obj[key]) {
->s : keyof T[keyof T]
+>s : Extract<keyof T[keyof T], string>
 >obj[key] : T[keyof T]
 >obj : T
 >key : keyof T
@@ -850,7 +850,7 @@ function f55<T, K extends keyof T>(obj: T, key: K) {
 >K : K
 
     for (let s in obj[key]) {
->s : keyof T[K]
+>s : Extract<keyof T[K], string>
 >obj[key] : T[K]
 >obj : T
 >key : K
@@ -873,17 +873,17 @@ function f60<T>(source: T, target: T) {
 >T : T
 
     for (let k in source) {
->k : keyof T
+>k : Extract<keyof T, string>
 >source : T
 
         target[k] = source[k];
->target[k] = source[k] : T[keyof T]
->target[k] : T[keyof T]
+>target[k] = source[k] : T[Extract<keyof T, string>]
+>target[k] : T[Extract<keyof T, string>]
 >target : T
->k : keyof T
->source[k] : T[keyof T]
+>k : Extract<keyof T, string>
+>source[k] : T[Extract<keyof T, string>]
 >source : T
->k : keyof T
+>k : Extract<keyof T, string>
     }
 }
 
@@ -2295,10 +2295,11 @@ new AnotherSampleClass({});
 >{} : {}
 
 // Positive repro from #17166
-function f3<T, K extends keyof T>(t: T, k: K, tk: T[K]): void {
->f3 : <T, K extends keyof T>(t: T, k: K, tk: T[K]) => void
+function f3<T, K extends Extract<keyof T, string>>(t: T, k: K, tk: T[K]): void {
+>f3 : <T, K extends Extract<keyof T, string>>(t: T, k: K, tk: T[K]) => void
 >T : T
 >K : K
+>Extract : Extract<T, U>
 >T : T
 >t : T
 >T : T
@@ -2309,19 +2310,19 @@ function f3<T, K extends keyof T>(t: T, k: K, tk: T[K]): void {
 >K : K
 
     for (let key in t) {
->key : keyof T
+>key : Extract<keyof T, string>
 >t : T
 
         key = k // ok, K ==> keyof T
 >key = k : K
->key : keyof T
+>key : Extract<keyof T, string>
 >k : K
 
         t[key] = tk; // ok, T[K] ==> T[keyof T]
 >t[key] = tk : T[K]
->t[key] : T[keyof T]
+>t[key] : T[Extract<keyof T, string>]
 >t : T
->key : keyof T
+>key : Extract<keyof T, string>
 >tk : T[K]
     }
 }
diff --git a/tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt b/tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt
index 44b8b4a6051..f9bb63c43b1 100644
--- a/tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt
+++ b/tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt
@@ -28,19 +28,22 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(76,5): error
     Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(77,5): error TS2322: Type 'keyof T | keyof U' is not assignable to type 'keyof (T | U)'.
   Type 'keyof T' is not assignable to type 'keyof (T | U)'.
-    Type 'string' is not assignable to type 'keyof (T | U)'.
-tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(86,9): error TS2322: Type 'keyof T' is not assignable to type 'K'.
-  Type 'string' is not assignable to type 'K'.
-tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(88,9): error TS2322: Type 'T[keyof T]' is not assignable to type 'T[K]'.
-  Type 'keyof T' is not assignable to type 'K'.
+    Type 'string | number | symbol' is not assignable to type 'keyof (T | U)'.
+      Type 'string' is not assignable to type 'keyof (T | U)'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(86,9): error TS2322: Type 'Extract<keyof T, string>' is not assignable to type 'K'.
+  Type 'string & keyof T' is not assignable to type 'K'.
+    Type 'string' is not assignable to type 'K'.
+tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(88,9): error TS2322: Type 'T[Extract<keyof T, string>]' is not assignable to type 'T[K]'.
+  Type 'Extract<keyof T, string>' is not assignable to type 'K'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(91,5): error TS2322: Type 'T[K]' is not assignable to type 'U[K]'.
   Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(94,5): error TS2322: Type 'T[J]' is not assignable to type 'U[J]'.
   Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(97,5): error TS2322: Type 'T[K]' is not assignable to type 'T[J]'.
   Type 'K' is not assignable to type 'J'.
-    Type 'keyof T' is not assignable to type 'J'.
-      Type 'string' is not assignable to type 'J'.
+    Type 'Extract<keyof T, string>' is not assignable to type 'J'.
+      Type 'string & keyof T' is not assignable to type 'J'.
+        Type 'string' is not assignable to type 'J'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(100,5): error TS2322: Type 'T[K]' is not assignable to type 'U[J]'.
   Type 'T' is not assignable to type 'U'.
 
@@ -178,24 +181,26 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(100,5): error
         ~~
 !!! error TS2322: Type 'keyof T | keyof U' is not assignable to type 'keyof (T | U)'.
 !!! error TS2322:   Type 'keyof T' is not assignable to type 'keyof (T | U)'.
-!!! error TS2322:     Type 'string' is not assignable to type 'keyof (T | U)'.
+!!! error TS2322:     Type 'string | number | symbol' is not assignable to type 'keyof (T | U)'.
+!!! error TS2322:       Type 'string' is not assignable to type 'keyof (T | U)'.
         k2 = k1;
     }
     
     // Repro from #17166
-    function f3<T, K extends keyof T, U extends T, J extends K>(
+    function f3<T, K extends Extract<keyof T, string>, U extends T, J extends K>(
         t: T, k: K, tk: T[K], u: U, j: J, uk: U[K], tj: T[J], uj: U[J]): void {
         for (let key in t) {
             key = k // ok, K ==> keyof T
             k = key // error, keyof T =/=> K
             ~
-!!! error TS2322: Type 'keyof T' is not assignable to type 'K'.
-!!! error TS2322:   Type 'string' is not assignable to type 'K'.
+!!! error TS2322: Type 'Extract<keyof T, string>' is not assignable to type 'K'.
+!!! error TS2322:   Type 'string & keyof T' is not assignable to type 'K'.
+!!! error TS2322:     Type 'string' is not assignable to type 'K'.
             t[key] = tk; // ok, T[K] ==> T[keyof T]
             tk = t[key]; // error, T[keyof T] =/=> T[K]
             ~~
-!!! error TS2322: Type 'T[keyof T]' is not assignable to type 'T[K]'.
-!!! error TS2322:   Type 'keyof T' is not assignable to type 'K'.
+!!! error TS2322: Type 'T[Extract<keyof T, string>]' is not assignable to type 'T[K]'.
+!!! error TS2322:   Type 'Extract<keyof T, string>' is not assignable to type 'K'.
         }
         tk = uk;
         uk = tk; // error
@@ -214,8 +219,9 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(100,5): error
         ~~
 !!! error TS2322: Type 'T[K]' is not assignable to type 'T[J]'.
 !!! error TS2322:   Type 'K' is not assignable to type 'J'.
-!!! error TS2322:     Type 'keyof T' is not assignable to type 'J'.
-!!! error TS2322:       Type 'string' is not assignable to type 'J'.
+!!! error TS2322:     Type 'Extract<keyof T, string>' is not assignable to type 'J'.
+!!! error TS2322:       Type 'string & keyof T' is not assignable to type 'J'.
+!!! error TS2322:         Type 'string' is not assignable to type 'J'.
     
         tk = uj;
         uj = tk; // error
diff --git a/tests/baselines/reference/keyofAndIndexedAccessErrors.js b/tests/baselines/reference/keyofAndIndexedAccessErrors.js
index d267699ffd6..0f026d5d2e5 100644
--- a/tests/baselines/reference/keyofAndIndexedAccessErrors.js
+++ b/tests/baselines/reference/keyofAndIndexedAccessErrors.js
@@ -80,7 +80,7 @@ function f20<T, U>(k1: keyof (T | U), k2: keyof (T & U), o1: T | U, o2: T & U) {
 }
 
 // Repro from #17166
-function f3<T, K extends keyof T, U extends T, J extends K>(
+function f3<T, K extends Extract<keyof T, string>, U extends T, J extends K>(
     t: T, k: K, tk: T[K], u: U, j: J, uk: U[K], tj: T[J], uj: U[J]): void {
     for (let key in t) {
         key = k // ok, K ==> keyof T
diff --git a/tests/baselines/reference/keyofAndIndexedAccessErrors.symbols b/tests/baselines/reference/keyofAndIndexedAccessErrors.symbols
index 47b22af2541..d062677fa02 100644
--- a/tests/baselines/reference/keyofAndIndexedAccessErrors.symbols
+++ b/tests/baselines/reference/keyofAndIndexedAccessErrors.symbols
@@ -270,18 +270,19 @@ function f20<T, U>(k1: keyof (T | U), k2: keyof (T & U), o1: T | U, o2: T & U) {
 }
 
 // Repro from #17166
-function f3<T, K extends keyof T, U extends T, J extends K>(
+function f3<T, K extends Extract<keyof T, string>, U extends T, J extends K>(
 >f3 : Symbol(f3, Decl(keyofAndIndexedAccessErrors.ts, 78, 1))
 >T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 81, 12))
 >K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 81, 14))
+>Extract : Symbol(Extract, Decl(lib.d.ts, --, --))
 >T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 81, 12))
->U : Symbol(U, Decl(keyofAndIndexedAccessErrors.ts, 81, 33))
+>U : Symbol(U, Decl(keyofAndIndexedAccessErrors.ts, 81, 50))
 >T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 81, 12))
->J : Symbol(J, Decl(keyofAndIndexedAccessErrors.ts, 81, 46))
+>J : Symbol(J, Decl(keyofAndIndexedAccessErrors.ts, 81, 63))
 >K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 81, 14))
 
     t: T, k: K, tk: T[K], u: U, j: J, uk: U[K], tj: T[J], uj: U[J]): void {
->t : Symbol(t, Decl(keyofAndIndexedAccessErrors.ts, 81, 60))
+>t : Symbol(t, Decl(keyofAndIndexedAccessErrors.ts, 81, 77))
 >T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 81, 12))
 >k : Symbol(k, Decl(keyofAndIndexedAccessErrors.ts, 82, 9))
 >K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 81, 14))
@@ -289,22 +290,22 @@ function f3<T, K extends keyof T, U extends T, J extends K>(
 >T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 81, 12))
 >K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 81, 14))
 >u : Symbol(u, Decl(keyofAndIndexedAccessErrors.ts, 82, 25))
->U : Symbol(U, Decl(keyofAndIndexedAccessErrors.ts, 81, 33))
+>U : Symbol(U, Decl(keyofAndIndexedAccessErrors.ts, 81, 50))
 >j : Symbol(j, Decl(keyofAndIndexedAccessErrors.ts, 82, 31))
->J : Symbol(J, Decl(keyofAndIndexedAccessErrors.ts, 81, 46))
+>J : Symbol(J, Decl(keyofAndIndexedAccessErrors.ts, 81, 63))
 >uk : Symbol(uk, Decl(keyofAndIndexedAccessErrors.ts, 82, 37))
->U : Symbol(U, Decl(keyofAndIndexedAccessErrors.ts, 81, 33))
+>U : Symbol(U, Decl(keyofAndIndexedAccessErrors.ts, 81, 50))
 >K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 81, 14))
 >tj : Symbol(tj, Decl(keyofAndIndexedAccessErrors.ts, 82, 47))
 >T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 81, 12))
->J : Symbol(J, Decl(keyofAndIndexedAccessErrors.ts, 81, 46))
+>J : Symbol(J, Decl(keyofAndIndexedAccessErrors.ts, 81, 63))
 >uj : Symbol(uj, Decl(keyofAndIndexedAccessErrors.ts, 82, 57))
->U : Symbol(U, Decl(keyofAndIndexedAccessErrors.ts, 81, 33))
->J : Symbol(J, Decl(keyofAndIndexedAccessErrors.ts, 81, 46))
+>U : Symbol(U, Decl(keyofAndIndexedAccessErrors.ts, 81, 50))
+>J : Symbol(J, Decl(keyofAndIndexedAccessErrors.ts, 81, 63))
 
     for (let key in t) {
 >key : Symbol(key, Decl(keyofAndIndexedAccessErrors.ts, 83, 12))
->t : Symbol(t, Decl(keyofAndIndexedAccessErrors.ts, 81, 60))
+>t : Symbol(t, Decl(keyofAndIndexedAccessErrors.ts, 81, 77))
 
         key = k // ok, K ==> keyof T
 >key : Symbol(key, Decl(keyofAndIndexedAccessErrors.ts, 83, 12))
@@ -315,13 +316,13 @@ function f3<T, K extends keyof T, U extends T, J extends K>(
 >key : Symbol(key, Decl(keyofAndIndexedAccessErrors.ts, 83, 12))
 
         t[key] = tk; // ok, T[K] ==> T[keyof T]
->t : Symbol(t, Decl(keyofAndIndexedAccessErrors.ts, 81, 60))
+>t : Symbol(t, Decl(keyofAndIndexedAccessErrors.ts, 81, 77))
 >key : Symbol(key, Decl(keyofAndIndexedAccessErrors.ts, 83, 12))
 >tk : Symbol(tk, Decl(keyofAndIndexedAccessErrors.ts, 82, 15))
 
         tk = t[key]; // error, T[keyof T] =/=> T[K]
 >tk : Symbol(tk, Decl(keyofAndIndexedAccessErrors.ts, 82, 15))
->t : Symbol(t, Decl(keyofAndIndexedAccessErrors.ts, 81, 60))
+>t : Symbol(t, Decl(keyofAndIndexedAccessErrors.ts, 81, 77))
 >key : Symbol(key, Decl(keyofAndIndexedAccessErrors.ts, 83, 12))
     }
     tk = uk;
diff --git a/tests/baselines/reference/keyofAndIndexedAccessErrors.types b/tests/baselines/reference/keyofAndIndexedAccessErrors.types
index bcd3878013d..2f50ef5c53c 100644
--- a/tests/baselines/reference/keyofAndIndexedAccessErrors.types
+++ b/tests/baselines/reference/keyofAndIndexedAccessErrors.types
@@ -22,7 +22,7 @@ type Dictionary<T> = { [x: string]: T };
 >T : T
 
 type T00 = keyof K0;  // Error
->T00 : string
+>T00 : string | number | symbol
 >K0 : No type information available!
 
 type T01 = keyof Object;
@@ -30,23 +30,23 @@ type T01 = keyof Object;
 >Object : Object
 
 type T02 = keyof keyof Object;
->T02 : "length" | "toString" | "valueOf" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr"
+>T02 : number | "length" | "toString" | "valueOf" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr"
 >Object : Object
 
 type T03 = keyof keyof keyof Object;
->T03 : "length" | "toString" | "valueOf" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr"
+>T03 : "toString" | "toLocaleString" | "valueOf"
 >Object : Object
 
 type T04 = keyof keyof keyof keyof Object;
->T04 : "length" | "toString" | "valueOf" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr"
+>T04 : number | "length" | "toString" | "valueOf" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr"
 >Object : Object
 
 type T05 = keyof keyof keyof keyof keyof Object;
->T05 : "length" | "toString" | "valueOf" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr"
+>T05 : "toString" | "toLocaleString" | "valueOf"
 >Object : Object
 
 type T06 = keyof keyof keyof keyof keyof keyof Object;
->T06 : "length" | "toString" | "valueOf" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr"
+>T06 : number | "length" | "toString" | "valueOf" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "substr"
 >Object : Object
 
 type T10 = Shape["name"];
@@ -301,10 +301,11 @@ function f20<T, U>(k1: keyof (T | U), k2: keyof (T & U), o1: T | U, o2: T & U) {
 }
 
 // Repro from #17166
-function f3<T, K extends keyof T, U extends T, J extends K>(
->f3 : <T, K extends keyof T, U extends T, J extends K>(t: T, k: K, tk: T[K], u: U, j: J, uk: U[K], tj: T[J], uj: U[J]) => void
+function f3<T, K extends Extract<keyof T, string>, U extends T, J extends K>(
+>f3 : <T, K extends Extract<keyof T, string>, U extends T, J extends K>(t: T, k: K, tk: T[K], u: U, j: J, uk: U[K], tj: T[J], uj: U[J]) => void
 >T : T
 >K : K
+>Extract : Extract<T, U>
 >T : T
 >U : U
 >T : T
@@ -334,32 +335,32 @@ function f3<T, K extends keyof T, U extends T, J extends K>(
 >J : J
 
     for (let key in t) {
->key : keyof T
+>key : Extract<keyof T, string>
 >t : T
 
         key = k // ok, K ==> keyof T
 >key = k : K
->key : keyof T
+>key : Extract<keyof T, string>
 >k : K
 
         k = key // error, keyof T =/=> K
->k = key : keyof T
+>k = key : Extract<keyof T, string>
 >k : K
->key : keyof T
+>key : Extract<keyof T, string>
 
         t[key] = tk; // ok, T[K] ==> T[keyof T]
 >t[key] = tk : T[K]
->t[key] : T[keyof T]
+>t[key] : T[Extract<keyof T, string>]
 >t : T
->key : keyof T
+>key : Extract<keyof T, string>
 >tk : T[K]
 
         tk = t[key]; // error, T[keyof T] =/=> T[K]
->tk = t[key] : T[keyof T]
+>tk = t[key] : T[Extract<keyof T, string>]
 >tk : T[K]
->t[key] : T[keyof T]
+>t[key] : T[Extract<keyof T, string>]
 >t : T
->key : keyof T
+>key : Extract<keyof T, string>
     }
     tk = uk;
 >tk = uk : U[K]
diff --git a/tests/baselines/reference/lateBoundConstraintTypeChecksCorrectly.errors.txt b/tests/baselines/reference/lateBoundConstraintTypeChecksCorrectly.errors.txt
deleted file mode 100644
index d9d573e0ab9..00000000000
--- a/tests/baselines/reference/lateBoundConstraintTypeChecksCorrectly.errors.txt
+++ /dev/null
@@ -1,29 +0,0 @@
-tests/cases/compiler/lateBoundConstraintTypeChecksCorrectly.ts(17,16): error TS2536: Type 'unique symbol' cannot be used to index type 'T'.
-tests/cases/compiler/lateBoundConstraintTypeChecksCorrectly.ts(18,17): error TS2536: Type 'unique symbol' cannot be used to index type 'T'.
-
-
-==== tests/cases/compiler/lateBoundConstraintTypeChecksCorrectly.ts (2 errors) ====
-    declare const fooProp: unique symbol;
-    declare const barProp: unique symbol;
-    
-    type BothProps = typeof fooProp | typeof barProp;
-    
-    export interface Foo<T> {
-      [fooProp]: T;
-      [barProp]: string;
-    }
-    
-    function f<T extends Foo<number>>(x: T) {
-        const abc = x[fooProp]; // expected: 'T[typeof fooProp]'
-    
-        /**
-         * Expected: no error
-         */
-        const def: T[typeof fooProp] = x[fooProp];
-                   ~~~~~~~~~~~~~~~~~
-!!! error TS2536: Type 'unique symbol' cannot be used to index type 'T'.
-        const def2: T[typeof barProp] = x[barProp];
-                    ~~~~~~~~~~~~~~~~~
-!!! error TS2536: Type 'unique symbol' cannot be used to index type 'T'.
-    }
-    
\ No newline at end of file
diff --git a/tests/baselines/reference/mappedTypeErrors.errors.txt b/tests/baselines/reference/mappedTypeErrors.errors.txt
index 3245f9932f0..f78c32531a4 100644
--- a/tests/baselines/reference/mappedTypeErrors.errors.txt
+++ b/tests/baselines/reference/mappedTypeErrors.errors.txt
@@ -1,7 +1,8 @@
 tests/cases/conformance/types/mapped/mappedTypeErrors.ts(19,20): error TS2313: Type parameter 'P' has a circular constraint.
-tests/cases/conformance/types/mapped/mappedTypeErrors.ts(20,20): error TS2322: Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/types/mapped/mappedTypeErrors.ts(21,20): error TS2322: Type 'Date' is not assignable to type 'string'.
-tests/cases/conformance/types/mapped/mappedTypeErrors.ts(22,19): error TS2344: Type 'Date' does not satisfy the constraint 'string'.
+tests/cases/conformance/types/mapped/mappedTypeErrors.ts(21,20): error TS2322: Type 'Date' is not assignable to type 'string | number | symbol'.
+  Type 'Date' is not assignable to type 'symbol'.
+tests/cases/conformance/types/mapped/mappedTypeErrors.ts(22,19): error TS2344: Type 'Date' does not satisfy the constraint 'string | number | symbol'.
+  Type 'Date' is not assignable to type 'symbol'.
 tests/cases/conformance/types/mapped/mappedTypeErrors.ts(25,24): error TS2344: Type '"foo"' does not satisfy the constraint '"name" | "width" | "height" | "visible"'.
 tests/cases/conformance/types/mapped/mappedTypeErrors.ts(26,24): error TS2344: Type '"name" | "foo"' does not satisfy the constraint '"name" | "width" | "height" | "visible"'.
   Type '"foo"' is not assignable to type '"name" | "width" | "height" | "visible"'.
@@ -45,11 +46,12 @@ tests/cases/conformance/types/mapped/mappedTypeErrors.ts(129,5): error TS2322: T
 tests/cases/conformance/types/mapped/mappedTypeErrors.ts(130,5): error TS2322: Type '{ a: string; }' is not assignable to type '{ [x: string]: any; a?: number | undefined; }'.
   Types of property 'a' are incompatible.
     Type 'string' is not assignable to type 'number | undefined'.
-tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,16): error TS2322: Type 'T' is not assignable to type 'string'.
+tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,16): error TS2322: Type 'T' is not assignable to type 'string | number | symbol'.
+  Type 'T' is not assignable to type 'symbol'.
 tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,21): error TS2536: Type 'P' cannot be used to index type 'T'.
 
 
-==== tests/cases/conformance/types/mapped/mappedTypeErrors.ts (26 errors) ====
+==== tests/cases/conformance/types/mapped/mappedTypeErrors.ts (25 errors) ====
     interface Shape {
         name: string;
         width: number;
@@ -72,14 +74,14 @@ tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,21): error TS2536:
                        ~
 !!! error TS2313: Type parameter 'P' has a circular constraint.
     type T01 = { [P in number]: string };  // Error
-                       ~~~~~~
-!!! error TS2322: Type 'number' is not assignable to type 'string'.
     type T02 = { [P in Date]: number };  // Error
                        ~~~~
-!!! error TS2322: Type 'Date' is not assignable to type 'string'.
+!!! error TS2322: Type 'Date' is not assignable to type 'string | number | symbol'.
+!!! error TS2322:   Type 'Date' is not assignable to type 'symbol'.
     type T03 = Record<Date, number>;  // Error
                       ~~~~
-!!! error TS2344: Type 'Date' does not satisfy the constraint 'string'.
+!!! error TS2344: Type 'Date' does not satisfy the constraint 'string | number | symbol'.
+!!! error TS2344:   Type 'Date' is not assignable to type 'symbol'.
     
     type T10 = Pick<Shape, "name">;
     type T11 = Pick<Shape, "foo">;  // Error
@@ -258,7 +260,8 @@ tests/cases/conformance/types/mapped/mappedTypeErrors.ts(136,21): error TS2536:
         pf: {[P in F]?: T[P]},
         pt: {[P in T]?: T[P]}, // note: should be in keyof T
                    ~
-!!! error TS2322: Type 'T' is not assignable to type 'string'.
+!!! error TS2322: Type 'T' is not assignable to type 'string | number | symbol'.
+!!! error TS2322:   Type 'T' is not assignable to type 'symbol'.
                         ~~~~
 !!! error TS2536: Type 'P' cannot be used to index type 'T'.
     };
diff --git a/tests/baselines/reference/mappedTypeErrors.types b/tests/baselines/reference/mappedTypeErrors.types
index ab0ae55a0e1..3faae85af8b 100644
--- a/tests/baselines/reference/mappedTypeErrors.types
+++ b/tests/baselines/reference/mappedTypeErrors.types
@@ -373,17 +373,17 @@ function setState<T, K extends keyof T>(obj: T, props: Pick<T, K>) {
 >K : K
 
     for (let k in props) {
->k : K
+>k : Extract<K, string>
 >props : Pick<T, K>
 
         obj[k] = props[k];
->obj[k] = props[k] : Pick<T, K>[K]
->obj[k] : T[K]
+>obj[k] = props[k] : Pick<T, K>[Extract<K, string>]
+>obj[k] : T[Extract<K, string>]
 >obj : T
->k : K
->props[k] : Pick<T, K>[K]
+>k : Extract<K, string>
+>props[k] : Pick<T, K>[Extract<K, string>]
 >props : Pick<T, K>
->k : K
+>k : Extract<K, string>
     }
 }
 
@@ -468,19 +468,19 @@ class C<T> {
 >K : K
 
         for (let k in props) {
->k : K
+>k : Extract<K, string>
 >props : Pick<T, K>
 
             this.state[k] = props[k];
->this.state[k] = props[k] : Pick<T, K>[K]
->this.state[k] : T[K]
+>this.state[k] = props[k] : Pick<T, K>[Extract<K, string>]
+>this.state[k] : T[Extract<K, string>]
 >this.state : T
 >this : this
 >state : T
->k : K
->props[k] : Pick<T, K>[K]
+>k : Extract<K, string>
+>props[k] : Pick<T, K>[Extract<K, string>]
 >props : Pick<T, K>
->k : K
+>k : Extract<K, string>
         }
     }
 }
diff --git a/tests/baselines/reference/mappedTypeRelationships.errors.txt b/tests/baselines/reference/mappedTypeRelationships.errors.txt
index ee49ef12283..26618cc15db 100644
--- a/tests/baselines/reference/mappedTypeRelationships.errors.txt
+++ b/tests/baselines/reference/mappedTypeRelationships.errors.txt
@@ -43,16 +43,20 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(143,5): error TS
     Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(148,5): error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type '{ [P in keyof U]: U[P]; }'.
   Type 'keyof U' is not assignable to type 'keyof T'.
-    Type 'string' is not assignable to type 'keyof T'.
+    Type 'string | number | symbol' is not assignable to type 'keyof T'.
+      Type 'string' is not assignable to type 'keyof T'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(153,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof T]: T[P]; }'.
   Type 'keyof T' is not assignable to type 'K'.
-    Type 'string' is not assignable to type 'K'.
+    Type 'string | number | symbol' is not assignable to type 'K'.
+      Type 'string' is not assignable to type 'K'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(158,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof U]: U[P]; }'.
   Type 'keyof U' is not assignable to type 'K'.
-    Type 'string' is not assignable to type 'K'.
+    Type 'string | number | symbol' is not assignable to type 'K'.
+      Type 'string' is not assignable to type 'K'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(163,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof T]: U[P]; }'.
   Type 'keyof T' is not assignable to type 'K'.
-    Type 'string' is not assignable to type 'K'.
+    Type 'string | number | symbol' is not assignable to type 'K'.
+      Type 'string' is not assignable to type 'K'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in K]: U[P]; }'.
   Type 'T[P]' is not assignable to type 'U[P]'.
     Type 'T' is not assignable to type 'U'.
@@ -276,7 +280,8 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
         ~
 !!! error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type '{ [P in keyof U]: U[P]; }'.
 !!! error TS2322:   Type 'keyof U' is not assignable to type 'keyof T'.
-!!! error TS2322:     Type 'string' is not assignable to type 'keyof T'.
+!!! error TS2322:     Type 'string | number | symbol' is not assignable to type 'keyof T'.
+!!! error TS2322:       Type 'string' is not assignable to type 'keyof T'.
     }
     
     function f73<T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P in keyof T]: T[P] }) {
@@ -285,7 +290,8 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
         ~
 !!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof T]: T[P]; }'.
 !!! error TS2322:   Type 'keyof T' is not assignable to type 'K'.
-!!! error TS2322:     Type 'string' is not assignable to type 'K'.
+!!! error TS2322:     Type 'string | number | symbol' is not assignable to type 'K'.
+!!! error TS2322:       Type 'string' is not assignable to type 'K'.
     }
     
     function f74<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P in keyof U]: U[P] }) {
@@ -294,7 +300,8 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
         ~
 !!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof U]: U[P]; }'.
 !!! error TS2322:   Type 'keyof U' is not assignable to type 'K'.
-!!! error TS2322:     Type 'string' is not assignable to type 'K'.
+!!! error TS2322:     Type 'string | number | symbol' is not assignable to type 'K'.
+!!! error TS2322:       Type 'string' is not assignable to type 'K'.
     }
     
     function f75<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P in keyof T]: U[P] }) {
@@ -303,7 +310,8 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(168,5): error TS
         ~
 !!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof T]: U[P]; }'.
 !!! error TS2322:   Type 'keyof T' is not assignable to type 'K'.
-!!! error TS2322:     Type 'string' is not assignable to type 'K'.
+!!! error TS2322:     Type 'string | number | symbol' is not assignable to type 'K'.
+!!! error TS2322:       Type 'string' is not assignable to type 'K'.
     }
     
     function f76<T, U extends T, K extends keyof T>(x: { [P in K]: T[P] }, y: { [P in K]: U[P] }) {
diff --git a/tests/baselines/reference/mappedTypeWithAny.types b/tests/baselines/reference/mappedTypeWithAny.types
index 36fad9140cc..6bf62c9730c 100644
--- a/tests/baselines/reference/mappedTypeWithAny.types
+++ b/tests/baselines/reference/mappedTypeWithAny.types
@@ -11,7 +11,7 @@ type ItemMap<T> = { [P in keyof T]: Item };
 >Item : Item
 
 declare let x0: keyof any;
->x0 : string
+>x0 : string | number | symbol
 
 declare let x1: { [P in any]: Item };
 >x1 : { [x: string]: Item; }
diff --git a/tests/baselines/reference/mappedTypes4.types b/tests/baselines/reference/mappedTypes4.types
index c003765d517..7292e143b42 100644
--- a/tests/baselines/reference/mappedTypes4.types
+++ b/tests/baselines/reference/mappedTypes4.types
@@ -40,19 +40,19 @@ function boxify<T>(obj: T): Boxified<T> {
 >T : T
 
         for (let k in obj) {
->k : keyof T
+>k : Extract<keyof T, string>
 >obj : T
 
             result[k] = { value: obj[k] };
->result[k] = { value: obj[k] } : { value: T[keyof T]; }
->result[k] : Boxified<T>[keyof T]
+>result[k] = { value: obj[k] } : { value: T[Extract<keyof T, string>]; }
+>result[k] : Boxified<T>[Extract<keyof T, string>]
 >result : Boxified<T>
->k : keyof T
->{ value: obj[k] } : { value: T[keyof T]; }
->value : T[keyof T]
->obj[k] : T[keyof T]
+>k : Extract<keyof T, string>
+>{ value: obj[k] } : { value: T[Extract<keyof T, string>]; }
+>value : T[Extract<keyof T, string>]
+>obj[k] : T[Extract<keyof T, string>]
 >obj : T
->k : keyof T
+>k : Extract<keyof T, string>
         }
         return result;
 >result : Boxified<T>
diff --git a/tests/baselines/reference/neverUnionIntersection.types b/tests/baselines/reference/neverUnionIntersection.types
index 5d9085e72e6..4f578052e9c 100644
--- a/tests/baselines/reference/neverUnionIntersection.types
+++ b/tests/baselines/reference/neverUnionIntersection.types
@@ -6,7 +6,7 @@ type T02 = string & never;
 >T02 : never
 
 type T03 = string | number | never;
->T03 : string | number
+>T03 : T03
 
 type T04 = string & number & never;
 >T04 : never
diff --git a/tests/baselines/reference/recursiveTypeRelations.errors.txt b/tests/baselines/reference/recursiveTypeRelations.errors.txt
index f29d5742185..8c5596958c3 100644
--- a/tests/baselines/reference/recursiveTypeRelations.errors.txt
+++ b/tests/baselines/reference/recursiveTypeRelations.errors.txt
@@ -6,7 +6,7 @@ tests/cases/compiler/recursiveTypeRelations.ts(27,61): error TS2304: Cannot find
 ==== tests/cases/compiler/recursiveTypeRelations.ts (3 errors) ====
     // Repro from #14896
     
-    type Attributes<Keys extends string> = {
+    type Attributes<Keys extends keyof any> = {
         [Key in Keys]: string;
     }
     
diff --git a/tests/baselines/reference/recursiveTypeRelations.js b/tests/baselines/reference/recursiveTypeRelations.js
index c477ecf1294..9c0887ab446 100644
--- a/tests/baselines/reference/recursiveTypeRelations.js
+++ b/tests/baselines/reference/recursiveTypeRelations.js
@@ -1,7 +1,7 @@
 //// [recursiveTypeRelations.ts]
 // Repro from #14896
 
-type Attributes<Keys extends string> = {
+type Attributes<Keys extends keyof any> = {
     [Key in Keys]: string;
 }
 
diff --git a/tests/baselines/reference/recursiveTypeRelations.symbols b/tests/baselines/reference/recursiveTypeRelations.symbols
index 2c940df2487..39032cd2f94 100644
--- a/tests/baselines/reference/recursiveTypeRelations.symbols
+++ b/tests/baselines/reference/recursiveTypeRelations.symbols
@@ -1,7 +1,7 @@
 === tests/cases/compiler/recursiveTypeRelations.ts ===
 // Repro from #14896
 
-type Attributes<Keys extends string> = {
+type Attributes<Keys extends keyof any> = {
 >Attributes : Symbol(Attributes, Decl(recursiveTypeRelations.ts, 0, 0))
 >Keys : Symbol(Keys, Decl(recursiveTypeRelations.ts, 2, 16))
 
diff --git a/tests/baselines/reference/recursiveTypeRelations.types b/tests/baselines/reference/recursiveTypeRelations.types
index ce6d007d066..b844031c0d1 100644
--- a/tests/baselines/reference/recursiveTypeRelations.types
+++ b/tests/baselines/reference/recursiveTypeRelations.types
@@ -1,7 +1,7 @@
 === tests/cases/compiler/recursiveTypeRelations.ts ===
 // Repro from #14896
 
-type Attributes<Keys extends string> = {
+type Attributes<Keys extends keyof any> = {
 >Attributes : { [Key in Keys]: string; }
 >Keys : Keys
 
diff --git a/tests/baselines/reference/typeGuardsTypeParameters.types b/tests/baselines/reference/typeGuardsTypeParameters.types
index 13fb9965235..c508c92a979 100644
--- a/tests/baselines/reference/typeGuardsTypeParameters.types
+++ b/tests/baselines/reference/typeGuardsTypeParameters.types
@@ -80,19 +80,19 @@ function fun<T>(item: { [P in keyof T]: T[P] }) {
 >[] : never[]
 
     for (const key in item) {
->key : keyof T
+>key : Extract<keyof T, string>
 >item : { [P in keyof T]: T[P]; }
 
         const value = item[key];
->value : { [P in keyof T]: T[P]; }[keyof T]
->item[key] : { [P in keyof T]: T[P]; }[keyof T]
+>value : { [P in keyof T]: T[P]; }[Extract<keyof T, string>]
+>item[key] : { [P in keyof T]: T[P]; }[Extract<keyof T, string>]
 >item : { [P in keyof T]: T[P]; }
->key : keyof T
+>key : Extract<keyof T, string>
 
         if (typeof value === "string") {
 >typeof value === "string" : boolean
 >typeof value : "string" | "number" | "boolean" | "symbol" | "undefined" | "object" | "function"
->value : { [P in keyof T]: T[P]; }[keyof T]
+>value : { [P in keyof T]: T[P]; }[Extract<keyof T, string>]
 >"string" : "string"
 
             strings.push(value);
@@ -100,7 +100,7 @@ function fun<T>(item: { [P in keyof T]: T[P] }) {
 >strings.push : (...items: string[]) => number
 >strings : string[]
 >push : (...items: string[]) => number
->value : { [P in keyof T]: T[P]; }[keyof T] & string
+>value : { [P in keyof T]: T[P]; }[Extract<keyof T, string>] & string
         }
     }
 }