Regression test for GH #20727

src/harness/unittests/extractConstants.ts

@@ -262,6 +262,12 @@ namespace N { // Force this test to be TS-only
         y = [#|this.x|];
     }
 }`);
+
+        // TODO (https://github.com/Microsoft/TypeScript/issues/20727): the extracted constant should have a type annotation.
+        testExtractConstant("extractConstant_ContextualType", `
+interface I { a: 1 | 2 | 3 }
+let i: I = [#|{ a: 1 }|];
+`);
     });
 
     function testExtractConstant(caption: string, text: string) {

tests/baselines/reference/extractConstant/extractConstant_ContextualType.ts

@@ -0,0 +1,10 @@
+// ==ORIGINAL==
+
+interface I { a: 1 | 2 | 3 }
+let i: I = /*[#|*/{ a: 1 }/*|]*/;
+
+// ==SCOPE::Extract to constant in enclosing scope==
+
+interface I { a: 1 | 2 | 3 }
+const newLocal = { a: 1 };
+let i: I = /*RENAME*/newLocal;