From f1eb9898fba3a7a52739fdc1a0119e77ad9c5331 Mon Sep 17 00:00:00 2001
From: Alexander T <alexander.tarasyuk@outlook.com>
Date: Tue, 17 Mar 2020 22:13:38 +0200
Subject: [PATCH] feat(36908): add 'property overwritten by spread' error for
 jsx attributes. add related span for conflicting declaration in spread
 (#37329)

---
 src/compiler/checker.ts                       |  33 +++---
 src/compiler/diagnosticMessages.json          |   4 +
 ...SpreadOverwritesAttributeStrict.errors.txt |  62 ++++++++++
 .../jsxSpreadOverwritesAttributeStrict.js     |  39 +++++++
 ...jsxSpreadOverwritesAttributeStrict.symbols |  86 ++++++++++++++
 .../jsxSpreadOverwritesAttributeStrict.types  | 106 ++++++++++++++++++
 .../reference/objectSpreadNegative.errors.txt |  13 ++-
 .../objectSpreadSetonlyAccessor.errors.txt    |   1 +
 .../spreadOverwritesPropertyStrict.errors.txt |   3 +
 .../jsxSpreadOverwritesAttributeStrict.tsx    |  29 +++++
 10 files changed, 362 insertions(+), 14 deletions(-)
 create mode 100644 tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.errors.txt
 create mode 100644 tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.js
 create mode 100644 tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.symbols
 create mode 100644 tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.types
 create mode 100644 tests/cases/conformance/jsx/jsxSpreadOverwritesAttributeStrict.tsx

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 7530f58d268..1bd276310e7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -22684,8 +22684,8 @@ namespace ts {
             // Grammar checking
             checkGrammarObjectLiteralExpression(node, inDestructuringPattern);
 
-            let propertiesTable: SymbolTable;
-            const allPropertiesTable = createSymbolTable();
+            const allPropertiesTable = strictNullChecks ? createSymbolTable() : undefined;
+            let propertiesTable = createSymbolTable();
             let propertiesArray: Symbol[] = [];
             let spread: Type = emptyObjectType;
 
@@ -22701,7 +22701,6 @@ namespace ts {
             let patternWithComputedProperties = false;
             let hasComputedStringProperty = false;
             let hasComputedNumberProperty = false;
-            propertiesTable = createSymbolTable();
 
             let offset = 0;
             for (let i = 0; i < node.properties.length; i++) {
@@ -22767,7 +22766,7 @@ namespace ts {
                     prop.type = type;
                     prop.target = member;
                     member = prop;
-                    allPropertiesTable.set(prop.escapedName, prop);
+                    allPropertiesTable?.set(prop.escapedName, prop);
                 }
                 else if (memberDecl.kind === SyntaxKind.SpreadAssignment) {
                     if (languageVersion < ScriptTarget.ES2015) {
@@ -22785,16 +22784,9 @@ namespace ts {
                         error(memberDecl, Diagnostics.Spread_types_may_only_be_created_from_object_types);
                         return errorType;
                     }
-                    for (const right of getPropertiesOfType(type)) {
-                        const rightType = getTypeOfSymbol(right);
-                        const left = allPropertiesTable.get(right.escapedName);
-                        if (strictNullChecks &&
-                            left &&
-                            !maybeTypeOfKind(rightType, TypeFlags.Nullable)) {
-                            error(left.valueDeclaration, Diagnostics._0_is_specified_more_than_once_so_this_usage_will_be_overwritten, unescapeLeadingUnderscores(left.escapedName));
-                        }
+                    if (allPropertiesTable) {
+                        checkSpreadPropOverrides(type, allPropertiesTable, memberDecl);
                     }
-
                     spread = getSpreadType(spread, type, node.symbol, objectFlags, inConstContext);
                     offset = i + 1;
                     continue;
@@ -22965,6 +22957,7 @@ namespace ts {
          */
         function createJsxAttributesTypeFromAttributesProperty(openingLikeElement: JsxOpeningLikeElement, checkMode: CheckMode | undefined) {
             const attributes = openingLikeElement.attributes;
+            const allAttributesTable = strictNullChecks ? createSymbolTable() : undefined;
             let attributesTable = createSymbolTable();
             let spread: Type = emptyJsxObjectType;
             let hasSpreadAnyType = false;
@@ -22988,6 +22981,7 @@ namespace ts {
                     attributeSymbol.type = exprType;
                     attributeSymbol.target = member;
                     attributesTable.set(attributeSymbol.escapedName, attributeSymbol);
+                    allAttributesTable?.set(attributeSymbol.escapedName, attributeSymbol);
                     if (attributeDecl.name.escapedText === jsxChildrenPropertyName) {
                         explicitlySpecifyChildrenAttribute = true;
                     }
@@ -23004,6 +22998,9 @@ namespace ts {
                     }
                     if (isValidSpreadType(exprType)) {
                         spread = getSpreadType(spread, exprType, attributes.symbol, objectFlags, /*readonly*/ false);
+                        if (allAttributesTable) {
+                            checkSpreadPropOverrides(exprType, allAttributesTable, attributeDecl);
+                        }
                     }
                     else {
                         typeToIntersect = typeToIntersect ? getIntersectionType([typeToIntersect, exprType]) : exprType;
@@ -23088,6 +23085,16 @@ namespace ts {
             return childrenTypes;
         }
 
+        function checkSpreadPropOverrides(type: Type, props: SymbolTable, spread: SpreadAssignment | JsxSpreadAttribute) {
+            for (const right of getPropertiesOfType(type)) {
+                const left = props.get(right.escapedName);
+                if (left && !maybeTypeOfKind(getTypeOfSymbol(right), TypeFlags.Nullable)) {
+                    const diagnostic = error(left.valueDeclaration, Diagnostics._0_is_specified_more_than_once_so_this_usage_will_be_overwritten, unescapeLeadingUnderscores(left.escapedName));
+                    addRelatedInfo(diagnostic, createDiagnosticForNode(spread, Diagnostics.This_spread_always_overwrites_this_property));
+                }
+            }
+        }
+
         /**
          * Check attributes property of opening-like element. This function is called during chooseOverload to get call signature of a JSX opening-like element.
          * (See "checkApplicableSignatureForJsxOpeningLikeElement" for how the function is used)
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 96144c02d77..a9f531c901c 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2907,6 +2907,10 @@
         "category": "Error",
         "code": 2784
     },
+    "This spread always overwrites this property.": {
+        "category": "Error",
+        "code": 2785
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
diff --git a/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.errors.txt b/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.errors.txt
new file mode 100644
index 00000000000..fefbc6cac4d
--- /dev/null
+++ b/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.errors.txt
@@ -0,0 +1,62 @@
+error TS2318: Cannot find global type 'CallableFunction'.
+error TS2318: Cannot find global type 'NewableFunction'.
+tests/cases/conformance/jsx/file.tsx(19,17): error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+tests/cases/conformance/jsx/file.tsx(20,17): error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+tests/cases/conformance/jsx/file.tsx(20,23): error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+tests/cases/conformance/jsx/file.tsx(21,17): error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+tests/cases/conformance/jsx/file.tsx(21,23): error TS2783: 'd' is specified more than once, so this usage will be overwritten.
+tests/cases/conformance/jsx/file.tsx(22,17): error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+tests/cases/conformance/jsx/file.tsx(22,17): error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+tests/cases/conformance/jsx/file.tsx(22,23): error TS2783: 'd' is specified more than once, so this usage will be overwritten.
+
+
+!!! error TS2318: Cannot find global type 'CallableFunction'.
+!!! error TS2318: Cannot find global type 'NewableFunction'.
+==== tests/cases/conformance/jsx/file.tsx (8 errors) ====
+    import React = require('react');
+    
+    interface Props {
+        a: number;
+        b: number;
+        c?: number;
+        d?: number;
+    }
+    
+    
+    const props: Props = { a: 1, b: 1 };
+    const Foo = (props: Props) => <div>{ props.a }</div>;
+    
+    // ok
+    const a1 = <Foo {...props}></Foo>;
+    const a2 = <Foo d={1} {...props}></Foo>;
+    
+    // error
+    const b1 = <Foo a={1} {...props}></Foo>;
+                    ~~~~~
+!!! error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/jsx/file.tsx:19:23: This spread always overwrites this property.
+    const b2 = <Foo a={1} b={2} {...props}></Foo>;
+                    ~~~~~
+!!! error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/jsx/file.tsx:20:29: This spread always overwrites this property.
+                          ~~~~~
+!!! error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/jsx/file.tsx:20:29: This spread always overwrites this property.
+    const b3 = <Foo a={1} d={1} {...props} {...{ d: 1 }}></Foo>;
+                    ~~~~~
+!!! error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/jsx/file.tsx:21:29: This spread always overwrites this property.
+                          ~~~~~
+!!! error TS2783: 'd' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/jsx/file.tsx:21:40: This spread always overwrites this property.
+    const b4 = <Foo a={1} d={1} {...props} {...{ a: 1, d: 1 }}></Foo>;
+                    ~~~~~
+!!! error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/jsx/file.tsx:22:29: This spread always overwrites this property.
+                    ~~~~~
+!!! error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/jsx/file.tsx:22:40: This spread always overwrites this property.
+                          ~~~~~
+!!! error TS2783: 'd' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/jsx/file.tsx:22:40: This spread always overwrites this property.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.js b/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.js
new file mode 100644
index 00000000000..8d7e5dd549a
--- /dev/null
+++ b/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.js
@@ -0,0 +1,39 @@
+//// [file.tsx]
+import React = require('react');
+
+interface Props {
+    a: number;
+    b: number;
+    c?: number;
+    d?: number;
+}
+
+
+const props: Props = { a: 1, b: 1 };
+const Foo = (props: Props) => <div>{ props.a }</div>;
+
+// ok
+const a1 = <Foo {...props}></Foo>;
+const a2 = <Foo d={1} {...props}></Foo>;
+
+// error
+const b1 = <Foo a={1} {...props}></Foo>;
+const b2 = <Foo a={1} b={2} {...props}></Foo>;
+const b3 = <Foo a={1} d={1} {...props} {...{ d: 1 }}></Foo>;
+const b4 = <Foo a={1} d={1} {...props} {...{ a: 1, d: 1 }}></Foo>;
+
+
+//// [file.jsx]
+"use strict";
+exports.__esModule = true;
+var React = require("react");
+var props = { a: 1, b: 1 };
+var Foo = function (props) { return <div>{props.a}</div>; };
+// ok
+var a1 = <Foo {...props}></Foo>;
+var a2 = <Foo d={1} {...props}></Foo>;
+// error
+var b1 = <Foo a={1} {...props}></Foo>;
+var b2 = <Foo a={1} b={2} {...props}></Foo>;
+var b3 = <Foo a={1} d={1} {...props} {...{ d: 1 }}></Foo>;
+var b4 = <Foo a={1} d={1} {...props} {...{ a: 1, d: 1 }}></Foo>;
diff --git a/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.symbols b/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.symbols
new file mode 100644
index 00000000000..0c0e4e74341
--- /dev/null
+++ b/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.symbols
@@ -0,0 +1,86 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+import React = require('react');
+>React : Symbol(React, Decl(file.tsx, 0, 0))
+
+interface Props {
+>Props : Symbol(Props, Decl(file.tsx, 0, 32))
+
+    a: number;
+>a : Symbol(Props.a, Decl(file.tsx, 2, 17))
+
+    b: number;
+>b : Symbol(Props.b, Decl(file.tsx, 3, 14))
+
+    c?: number;
+>c : Symbol(Props.c, Decl(file.tsx, 4, 14))
+
+    d?: number;
+>d : Symbol(Props.d, Decl(file.tsx, 5, 15))
+}
+
+
+const props: Props = { a: 1, b: 1 };
+>props : Symbol(props, Decl(file.tsx, 10, 5))
+>Props : Symbol(Props, Decl(file.tsx, 0, 32))
+>a : Symbol(a, Decl(file.tsx, 10, 22))
+>b : Symbol(b, Decl(file.tsx, 10, 28))
+
+const Foo = (props: Props) => <div>{ props.a }</div>;
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+>props : Symbol(props, Decl(file.tsx, 11, 13))
+>Props : Symbol(Props, Decl(file.tsx, 0, 32))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react.d.ts, 2400, 45))
+>props.a : Symbol(Props.a, Decl(file.tsx, 2, 17))
+>props : Symbol(props, Decl(file.tsx, 11, 13))
+>a : Symbol(Props.a, Decl(file.tsx, 2, 17))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react.d.ts, 2400, 45))
+
+// ok
+const a1 = <Foo {...props}></Foo>;
+>a1 : Symbol(a1, Decl(file.tsx, 14, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+>props : Symbol(props, Decl(file.tsx, 10, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+
+const a2 = <Foo d={1} {...props}></Foo>;
+>a2 : Symbol(a2, Decl(file.tsx, 15, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+>d : Symbol(d, Decl(file.tsx, 15, 15))
+>props : Symbol(props, Decl(file.tsx, 10, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+
+// error
+const b1 = <Foo a={1} {...props}></Foo>;
+>b1 : Symbol(b1, Decl(file.tsx, 18, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+>a : Symbol(a, Decl(file.tsx, 18, 15))
+>props : Symbol(props, Decl(file.tsx, 10, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+
+const b2 = <Foo a={1} b={2} {...props}></Foo>;
+>b2 : Symbol(b2, Decl(file.tsx, 19, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+>a : Symbol(a, Decl(file.tsx, 19, 15))
+>b : Symbol(b, Decl(file.tsx, 19, 21))
+>props : Symbol(props, Decl(file.tsx, 10, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+
+const b3 = <Foo a={1} d={1} {...props} {...{ d: 1 }}></Foo>;
+>b3 : Symbol(b3, Decl(file.tsx, 20, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+>a : Symbol(a, Decl(file.tsx, 20, 15))
+>d : Symbol(d, Decl(file.tsx, 20, 21))
+>props : Symbol(props, Decl(file.tsx, 10, 5))
+>d : Symbol(d, Decl(file.tsx, 20, 44))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+
+const b4 = <Foo a={1} d={1} {...props} {...{ a: 1, d: 1 }}></Foo>;
+>b4 : Symbol(b4, Decl(file.tsx, 21, 5))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+>a : Symbol(a, Decl(file.tsx, 21, 15))
+>d : Symbol(d, Decl(file.tsx, 21, 21))
+>props : Symbol(props, Decl(file.tsx, 10, 5))
+>a : Symbol(a, Decl(file.tsx, 21, 44))
+>d : Symbol(d, Decl(file.tsx, 21, 50))
+>Foo : Symbol(Foo, Decl(file.tsx, 11, 5))
+
diff --git a/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.types b/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.types
new file mode 100644
index 00000000000..37eca94cbcc
--- /dev/null
+++ b/tests/baselines/reference/jsxSpreadOverwritesAttributeStrict.types
@@ -0,0 +1,106 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+import React = require('react');
+>React : typeof React
+
+interface Props {
+    a: number;
+>a : number
+
+    b: number;
+>b : number
+
+    c?: number;
+>c : number | undefined
+
+    d?: number;
+>d : number | undefined
+}
+
+
+const props: Props = { a: 1, b: 1 };
+>props : Props
+>{ a: 1, b: 1 } : { a: number; b: number; }
+>a : number
+>1 : 1
+>b : number
+>1 : 1
+
+const Foo = (props: Props) => <div>{ props.a }</div>;
+>Foo : (props: Props) => JSX.Element
+>(props: Props) => <div>{ props.a }</div> : (props: Props) => JSX.Element
+>props : Props
+><div>{ props.a }</div> : JSX.Element
+>div : any
+>props.a : number
+>props : Props
+>a : number
+>div : any
+
+// ok
+const a1 = <Foo {...props}></Foo>;
+>a1 : JSX.Element
+><Foo {...props}></Foo> : JSX.Element
+>Foo : (props: Props) => JSX.Element
+>props : Props
+>Foo : (props: Props) => JSX.Element
+
+const a2 = <Foo d={1} {...props}></Foo>;
+>a2 : JSX.Element
+><Foo d={1} {...props}></Foo> : JSX.Element
+>Foo : (props: Props) => JSX.Element
+>d : number
+>1 : 1
+>props : Props
+>Foo : (props: Props) => JSX.Element
+
+// error
+const b1 = <Foo a={1} {...props}></Foo>;
+>b1 : JSX.Element
+><Foo a={1} {...props}></Foo> : JSX.Element
+>Foo : (props: Props) => JSX.Element
+>a : number
+>1 : 1
+>props : Props
+>Foo : (props: Props) => JSX.Element
+
+const b2 = <Foo a={1} b={2} {...props}></Foo>;
+>b2 : JSX.Element
+><Foo a={1} b={2} {...props}></Foo> : JSX.Element
+>Foo : (props: Props) => JSX.Element
+>a : number
+>1 : 1
+>b : number
+>2 : 2
+>props : Props
+>Foo : (props: Props) => JSX.Element
+
+const b3 = <Foo a={1} d={1} {...props} {...{ d: 1 }}></Foo>;
+>b3 : JSX.Element
+><Foo a={1} d={1} {...props} {...{ d: 1 }}></Foo> : JSX.Element
+>Foo : (props: Props) => JSX.Element
+>a : number
+>1 : 1
+>d : number
+>1 : 1
+>props : Props
+>{ d: 1 } : { d: number; }
+>d : number
+>1 : 1
+>Foo : (props: Props) => JSX.Element
+
+const b4 = <Foo a={1} d={1} {...props} {...{ a: 1, d: 1 }}></Foo>;
+>b4 : JSX.Element
+><Foo a={1} d={1} {...props} {...{ a: 1, d: 1 }}></Foo> : JSX.Element
+>Foo : (props: Props) => JSX.Element
+>a : number
+>1 : 1
+>d : number
+>1 : 1
+>props : Props
+>{ a: 1, d: 1 } : { a: number; d: number; }
+>a : number
+>1 : 1
+>d : number
+>1 : 1
+>Foo : (props: Props) => JSX.Element
+
diff --git a/tests/baselines/reference/objectSpreadNegative.errors.txt b/tests/baselines/reference/objectSpreadNegative.errors.txt
index 8b0ae9abbc5..397e7e134e0 100644
--- a/tests/baselines/reference/objectSpreadNegative.errors.txt
+++ b/tests/baselines/reference/objectSpreadNegative.errors.txt
@@ -10,6 +10,7 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(28,36): error TS230
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(28,53): error TS2300: Duplicate identifier 'b'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(32,7): error TS2783: 'b' is specified more than once, so this usage will be overwritten.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(37,7): error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+tests/cases/conformance/types/spread/objectSpreadNegative.ts(37,7): error TS2783: 'b' is specified more than once, so this usage will be overwritten.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(39,14): error TS2783: 'b' is specified more than once, so this usage will be overwritten.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(41,53): error TS2783: 'd' is specified more than once, so this usage will be overwritten.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(43,7): error TS2783: 'a' is specified more than once, so this usage will be overwritten.
@@ -26,7 +27,7 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(69,9): error TS2339
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(74,11): error TS2339: Property 'a' does not exist on type '{}'.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (22 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (23 errors) ====
     let o = { a: 1, b: 'no' }
     
     /// private propagates
@@ -70,6 +71,7 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(74,11): error TS233
     let duplicated = { b: 'bad', ...o, b: 'bad', ...o2, b: 'bad' }
                        ~~~~~~~~
 !!! error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadNegative.ts:28:30: This spread always overwrites this property.
                                        ~
 !!! error TS2300: Duplicate identifier 'b'.
                                                         ~
@@ -80,6 +82,7 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(74,11): error TS233
         { b: 'ignored', ...o }
           ~~~~~~~~~~~~
 !!! error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadNegative.ts:32:21: This spread always overwrites this property.
     
     let o3 = { a: 1, b: 'no' }
     let o4 = { b: 'yes', c: true }
@@ -87,22 +90,30 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(74,11): error TS233
         { b: 'ok', ...o3, ...o4 }
           ~~~~~~~
 !!! error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadNegative.ts:37:16: This spread always overwrites this property.
+          ~~~~~~~
+!!! error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadNegative.ts:37:23: This spread always overwrites this property.
     let combinedMid: { a: number, b: string, c: boolean } =
         { ...o3, b: 'ok', ...o4 }
                  ~~~~~~~
 !!! error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadNegative.ts:39:23: This spread always overwrites this property.
     let combinedNested: { a: number, b: boolean, c: string, d: string } =
         { ...{ a: 4, ...{ b: false, c: 'overriden' } }, d: 'actually new', ...{ a: 5, d: 'maybe new' } }
                                                         ~~~~~~~~~~~~~~~~~
 !!! error TS2783: 'd' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadNegative.ts:41:72: This spread always overwrites this property.
     let changeTypeBefore: { a: number, b: string } =
         { a: 'wrong type?', ...o3 };
           ~~~~~~~~~~~~~~~~
 !!! error TS2783: 'a' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadNegative.ts:43:25: This spread always overwrites this property.
     let computedMiddle: { a: number, b: string, c: boolean, "in the middle": number } =
         { ...o3, ['in the middle']: 13, b: 'maybe?', ...o4 }
                                         ~~~~~~~~~~~
 !!! error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadNegative.ts:45:50: This spread always overwrites this property.
     
     // primitives are not allowed, except for falsy ones
     let spreadNum = { ...12 };
diff --git a/tests/baselines/reference/objectSpreadSetonlyAccessor.errors.txt b/tests/baselines/reference/objectSpreadSetonlyAccessor.errors.txt
index cb3eb23d972..bbf419d6b7a 100644
--- a/tests/baselines/reference/objectSpreadSetonlyAccessor.errors.txt
+++ b/tests/baselines/reference/objectSpreadSetonlyAccessor.errors.txt
@@ -6,4 +6,5 @@ tests/cases/conformance/types/spread/objectSpreadSetonlyAccessor.ts(2,34): error
     const o2: { foo: undefined } = { foo: 1, ... { set foo(_v: number) { } } }
                                      ~~~~~~
 !!! error TS2783: 'foo' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/objectSpreadSetonlyAccessor.ts:2:42: This spread always overwrites this property.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/spreadOverwritesPropertyStrict.errors.txt b/tests/baselines/reference/spreadOverwritesPropertyStrict.errors.txt
index be9054dfc51..b671a9ca73d 100644
--- a/tests/baselines/reference/spreadOverwritesPropertyStrict.errors.txt
+++ b/tests/baselines/reference/spreadOverwritesPropertyStrict.errors.txt
@@ -9,6 +9,7 @@ tests/cases/conformance/types/spread/spreadOverwritesPropertyStrict.ts(24,14): e
     var unused1 = { b: 1, ...ab } // error
                     ~~~~
 !!! error TS2783: 'b' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/spreadOverwritesPropertyStrict.ts:3:23: This spread always overwrites this property.
     var unused2 = { ...ab, ...ab } // ok, overwritten error doesn't apply to spreads
     var unused3 = { b: 1, ...abq } // ok, abq might have b: undefined
     var unused4 = { ...ab, b: 1 } // ok, we don't care that b in ab is overwritten
@@ -23,6 +24,7 @@ tests/cases/conformance/types/spread/spreadOverwritesPropertyStrict.ts(24,14): e
         return { x: 1, ...obj } // error
                  ~~~~
 !!! error TS2783: 'x' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/spreadOverwritesPropertyStrict.ts:15:20: This spread always overwrites this property.
     }
     function i(b: boolean, t: { command: string, ok: string }) {
         return { command: "hi", ...(b ? t : {}) } // ok
@@ -34,5 +36,6 @@ tests/cases/conformance/types/spread/spreadOverwritesPropertyStrict.ts(24,14): e
         return { command: "hi", ...{ spoiler: true }, spoiler2: true, ...t } // error
                  ~~~~~~~~~~~~~
 !!! error TS2783: 'command' is specified more than once, so this usage will be overwritten.
+!!! related TS2785 tests/cases/conformance/types/spread/spreadOverwritesPropertyStrict.ts:24:67: This spread always overwrites this property.
     }
     
\ No newline at end of file
diff --git a/tests/cases/conformance/jsx/jsxSpreadOverwritesAttributeStrict.tsx b/tests/cases/conformance/jsx/jsxSpreadOverwritesAttributeStrict.tsx
new file mode 100644
index 00000000000..1b7d7133a54
--- /dev/null
+++ b/tests/cases/conformance/jsx/jsxSpreadOverwritesAttributeStrict.tsx
@@ -0,0 +1,29 @@
+// @filename: file.tsx
+// @jsx: preserve
+// @strict: true
+// @noLib: true
+// @skipLibCheck: true
+// @libFiles: react.d.ts,lib.d.ts
+
+import React = require('react');
+
+interface Props {
+    a: number;
+    b: number;
+    c?: number;
+    d?: number;
+}
+
+
+const props: Props = { a: 1, b: 1 };
+const Foo = (props: Props) => <div>{ props.a }</div>;
+
+// ok
+const a1 = <Foo {...props}></Foo>;
+const a2 = <Foo d={1} {...props}></Foo>;
+
+// error
+const b1 = <Foo a={1} {...props}></Foo>;
+const b2 = <Foo a={1} b={2} {...props}></Foo>;
+const b3 = <Foo a={1} d={1} {...props} {...{ d: 1 }}></Foo>;
+const b4 = <Foo a={1} d={1} {...props} {...{ a: 1, d: 1 }}></Foo>;