diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index cb855969ea8fc..a193c01272adc 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -14214,9 +14214,13 @@ namespace ts {
/**
* Check if a property with the given name is known anywhere in the given type. In an object type, a property
- * is considered known if the object type is empty and the check is for assignability, if the object type has
- * index signatures, or if the property is actually declared in the object type. In a union or intersection
- * type, a property is considered known if it is known in any constituent type.
+ * is considered known if
+ * 1. the object type is empty and the check is for assignability, or
+ * 2. if the object type has index signatures, or
+ * 3. if the property is actually declared in the object type
+ * (this means that 'toString', for example, is not usually a known property).
+ * 4. In a union or intersection type,
+ * a property is considered known if it is known in any constituent type.
* @param targetType a type to search a given name in
* @param name a property name to search
* @param isComparingJsxAttributes a boolean flag indicating whether we are searching in JsxAttributesType
@@ -14226,7 +14230,7 @@ namespace ts {
const resolved = resolveStructuredTypeMembers(<ObjectType>targetType);
if (resolved.stringIndexInfo ||
resolved.numberIndexInfo && isNumericLiteralName(name) ||
- getPropertyOfType(targetType, name) ||
+ getPropertyOfObjectType(targetType, name) ||
isComparingJsxAttributes && !isUnhyphenatedJsxName(name)) {
// For JSXAttributes, if the attribute has a hyphenated name, consider that the attribute to be known.
return true;
diff --git a/tests/baselines/reference/generatorTypeCheck63.errors.txt b/tests/baselines/reference/generatorTypeCheck63.errors.txt
index ed2ed36a438da..c08635e8b730b 100644
--- a/tests/baselines/reference/generatorTypeCheck63.errors.txt
+++ b/tests/baselines/reference/generatorTypeCheck63.errors.txt
@@ -1,11 +1,12 @@
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts(24,14): error TS2322: Type '(a: State | 1) => IterableIterator<State | 1>' is not assignable to type 'Strategy<State>'.
- Type 'IterableIterator<State | 1>' is not assignable to type 'IterableIterator<State>'.
- Type 'State | 1' is not assignable to type 'State'.
- Type '1' is not assignable to type 'State'.
+tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts(24,61): error TS2345: Argument of type '(state: State) => IterableIterator<State | 1>' is not assignable to parameter of type '(a: StrategicState) => IterableIterator<StrategicState>'.
+ Type 'IterableIterator<State | 1>' is not assignable to type 'IterableIterator<StrategicState>'.
+ Type 'State | 1' is not assignable to type 'StrategicState'.
+ Type '1' has no properties in common with type 'StrategicState'.
tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts(29,70): error TS7025: Generator implicitly has type 'IterableIterator<any>' because it does not yield any values. Consider supplying a return type.
tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts(32,42): error TS2453: The type argument for type parameter 'T' cannot be inferred from the usage. Consider specifying the type arguments explicitly.
Type argument candidate 'State' is not a valid type argument because it is not a supertype of candidate '1'.
-tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts(36,14): error TS2322: Type '(a: State | 1) => IterableIterator<State | 1>' is not assignable to type 'Strategy<State>'.
+tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts(36,62): error TS2345: Argument of type '(state: State) => IterableIterator<State | 1>' is not assignable to parameter of type '(a: StrategicState) => IterableIterator<StrategicState>'.
+ Type 'IterableIterator<State | 1>' is not assignable to type 'IterableIterator<StrategicState>'.
==== tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts (4 errors) ====
@@ -33,11 +34,11 @@ tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts(36,14): err
}
export const Nothing: Strategy<State> = strategy("Nothing", function* (state: State) {
- ~~~~~~~
-!!! error TS2322: Type '(a: State | 1) => IterableIterator<State | 1>' is not assignable to type 'Strategy<State>'.
-!!! error TS2322: Type 'IterableIterator<State | 1>' is not assignable to type 'IterableIterator<State>'.
-!!! error TS2322: Type 'State | 1' is not assignable to type 'State'.
-!!! error TS2322: Type '1' is not assignable to type 'State'.
+ ~~~~~~~~
+!!! error TS2345: Argument of type '(state: State) => IterableIterator<State | 1>' is not assignable to parameter of type '(a: StrategicState) => IterableIterator<StrategicState>'.
+!!! error TS2345: Type 'IterableIterator<State | 1>' is not assignable to type 'IterableIterator<StrategicState>'.
+!!! error TS2345: Type 'State | 1' is not assignable to type 'StrategicState'.
+!!! error TS2345: Type '1' has no properties in common with type 'StrategicState'.
yield 1;
return state;
});
@@ -55,8 +56,9 @@ tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck63.ts(36,14): err
});
export const Nothing3: Strategy<State> = strategy("Nothing", function* (state: State) {
- ~~~~~~~~
-!!! error TS2322: Type '(a: State | 1) => IterableIterator<State | 1>' is not assignable to type 'Strategy<State>'.
+ ~~~~~~~~
+!!! error TS2345: Argument of type '(state: State) => IterableIterator<State | 1>' is not assignable to parameter of type '(a: StrategicState) => IterableIterator<StrategicState>'.
+!!! error TS2345: Type 'IterableIterator<State | 1>' is not assignable to type 'IterableIterator<StrategicState>'.
yield state;
return 1;
});
\ No newline at end of file
diff --git a/tests/baselines/reference/objectLiteralFunctionArgContextualTyping2.errors.txt b/tests/baselines/reference/objectLiteralFunctionArgContextualTyping2.errors.txt
index b967b227809e2..0117d2c0c8c23 100644
--- a/tests/baselines/reference/objectLiteralFunctionArgContextualTyping2.errors.txt
+++ b/tests/baselines/reference/objectLiteralFunctionArgContextualTyping2.errors.txt
@@ -4,12 +4,12 @@ tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(9,4): error TS
Property 'doStuff' is missing in type '{ value: string; }'.
tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(10,17): error TS2345: Argument of type '{ value: string; what: number; }' is not assignable to parameter of type 'I2'.
Object literal may only specify known properties, and 'what' does not exist in type 'I2'.
-tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(11,4): error TS2345: Argument of type '{ toString: (s: any) => any; }' is not assignable to parameter of type 'I2'.
- Property 'value' is missing in type '{ toString: (s: any) => any; }'.
-tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(12,4): error TS2345: Argument of type '{ toString: (s: string) => string; }' is not assignable to parameter of type 'I2'.
- Property 'value' is missing in type '{ toString: (s: string) => string; }'.
-tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(13,4): error TS2345: Argument of type '{ value: string; toString: (s: any) => any; }' is not assignable to parameter of type 'I2'.
- Property 'doStuff' is missing in type '{ value: string; toString: (s: any) => any; }'.
+tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(11,6): error TS2345: Argument of type '{ toString: (s: any) => any; }' is not assignable to parameter of type 'I2'.
+ Object literal may only specify known properties, and 'toString' does not exist in type 'I2'.
+tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(12,6): error TS2345: Argument of type '{ toString: (s: string) => string; }' is not assignable to parameter of type 'I2'.
+ Object literal may only specify known properties, and 'toString' does not exist in type 'I2'.
+tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(13,17): error TS2345: Argument of type '{ value: string; toString: (s: any) => any; }' is not assignable to parameter of type 'I2'.
+ Object literal may only specify known properties, and 'toString' does not exist in type 'I2'.
==== tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts (6 errors) ====
@@ -33,14 +33,14 @@ tests/cases/compiler/objectLiteralFunctionArgContextualTyping2.ts(13,4): error T
!!! error TS2345: Argument of type '{ value: string; what: number; }' is not assignable to parameter of type 'I2'.
!!! error TS2345: Object literal may only specify known properties, and 'what' does not exist in type 'I2'.
f2({ toString: (s) => s })
- ~~~~~~~~~~~~~~~~~~~~~~
+ ~~~~~~~~~~~~~~~~~~
!!! error TS2345: Argument of type '{ toString: (s: any) => any; }' is not assignable to parameter of type 'I2'.
-!!! error TS2345: Property 'value' is missing in type '{ toString: (s: any) => any; }'.
+!!! error TS2345: Object literal may only specify known properties, and 'toString' does not exist in type 'I2'.
f2({ toString: (s: string) => s })
- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! error TS2345: Argument of type '{ toString: (s: string) => string; }' is not assignable to parameter of type 'I2'.
-!!! error TS2345: Property 'value' is missing in type '{ toString: (s: string) => string; }'.
+!!! error TS2345: Object literal may only specify known properties, and 'toString' does not exist in type 'I2'.
f2({ value: '', toString: (s) => s.uhhh })
- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ ~~~~~~~~~~~~~~~~~~~~~~~
!!! error TS2345: Argument of type '{ value: string; toString: (s: any) => any; }' is not assignable to parameter of type 'I2'.
-!!! error TS2345: Property 'doStuff' is missing in type '{ value: string; toString: (s: any) => any; }'.
\ No newline at end of file
+!!! error TS2345: Object literal may only specify known properties, and 'toString' does not exist in type 'I2'.
\ No newline at end of file
diff --git a/tests/baselines/reference/tsxSpreadAttributesResolution1.js b/tests/baselines/reference/tsxSpreadAttributesResolution1.js
index f8c3cfbb5946d..7d83e9bd39067 100644
--- a/tests/baselines/reference/tsxSpreadAttributesResolution1.js
+++ b/tests/baselines/reference/tsxSpreadAttributesResolution1.js
@@ -7,11 +7,12 @@ class Poisoned extends React.Component<{}, {}> {
}
}
-const obj: Object = {};
+const obj = {};
// OK
let p = <Poisoned {...obj} />;
-let y = <Poisoned />;
+let y = <Poisoned />;
+
//// [file.jsx]
"use strict";
diff --git a/tests/baselines/reference/tsxSpreadAttributesResolution1.symbols b/tests/baselines/reference/tsxSpreadAttributesResolution1.symbols
index 82a4e5cc82271..9b3f535f309b6 100644
--- a/tests/baselines/reference/tsxSpreadAttributesResolution1.symbols
+++ b/tests/baselines/reference/tsxSpreadAttributesResolution1.symbols
@@ -17,9 +17,8 @@ class Poisoned extends React.Component<{}, {}> {
}
}
-const obj: Object = {};
+const obj = {};
>obj : Symbol(obj, Decl(file.tsx, 8, 5))
->Object : Symbol(Object, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
// OK
let p = <Poisoned {...obj} />;
diff --git a/tests/baselines/reference/tsxSpreadAttributesResolution1.types b/tests/baselines/reference/tsxSpreadAttributesResolution1.types
index f8f1cb8d15ad8..26f83c740013d 100644
--- a/tests/baselines/reference/tsxSpreadAttributesResolution1.types
+++ b/tests/baselines/reference/tsxSpreadAttributesResolution1.types
@@ -18,9 +18,8 @@ class Poisoned extends React.Component<{}, {}> {
}
}
-const obj: Object = {};
->obj : Object
->Object : Object
+const obj = {};
+>obj : {}
>{} : {}
// OK
@@ -28,7 +27,7 @@ let p = <Poisoned {...obj} />;
>p : JSX.Element
><Poisoned {...obj} /> : JSX.Element
>Poisoned : typeof Poisoned
->obj : Object
+>obj : {}
let y = <Poisoned />;
>y : JSX.Element
diff --git a/tests/baselines/reference/weakType.errors.txt b/tests/baselines/reference/weakType.errors.txt
index 7064ace5daaaa..441ef70ac1674 100644
--- a/tests/baselines/reference/weakType.errors.txt
+++ b/tests/baselines/reference/weakType.errors.txt
@@ -1,11 +1,14 @@
-tests/cases/compiler/weakType.ts(31,18): error TS2559: Type '{ error?: number; }' has no properties in common with type 'ChangeOptions'.
-tests/cases/compiler/weakType.ts(56,5): error TS2322: Type '{ properties: { wrong: string; }; }' is not assignable to type 'Weak & Spoiler'.
+tests/cases/compiler/weakType.ts(16,13): error TS2559: Type '12' has no properties in common with type 'Settings'.
+tests/cases/compiler/weakType.ts(17,13): error TS2559: Type '"completely wrong"' has no properties in common with type 'Settings'.
+tests/cases/compiler/weakType.ts(18,13): error TS2559: Type 'false' has no properties in common with type 'Settings'.
+tests/cases/compiler/weakType.ts(35,18): error TS2559: Type '{ error?: number; }' has no properties in common with type 'ChangeOptions'.
+tests/cases/compiler/weakType.ts(60,5): error TS2322: Type '{ properties: { wrong: string; }; }' is not assignable to type 'Weak & Spoiler'.
Type '{ properties: { wrong: string; }; }' is not assignable to type 'Weak'.
Types of property 'properties' are incompatible.
Type '{ wrong: string; }' has no properties in common with type '{ b?: number; }'.
-==== tests/cases/compiler/weakType.ts (2 errors) ====
+==== tests/cases/compiler/weakType.ts (5 errors) ====
interface Settings {
timeout?: number;
onError?(): void;
@@ -16,10 +19,20 @@ tests/cases/compiler/weakType.ts(56,5): error TS2322: Type '{ properties: { wron
}
function doSomething(settings: Settings) { /* ... */ }
-
// forgot to call `getDefaultSettings`
// but it is not caught because we don't check for call signatures
doSomething(getDefaultSettings);
+ // same for arrow expressions:
+ doSomething(() => { });
+ doSomething(12);
+ ~~
+!!! error TS2559: Type '12' has no properties in common with type 'Settings'.
+ doSomething('completely wrong');
+ ~~~~~~~~~~~~~~~~~~
+!!! error TS2559: Type '"completely wrong"' has no properties in common with type 'Settings'.
+ doSomething(false);
+ ~~~~~
+!!! error TS2559: Type 'false' has no properties in common with type 'Settings'.
// this is an oddly popular way of defining settings
// this example is from services/textChanges.ts
diff --git a/tests/baselines/reference/weakType.js b/tests/baselines/reference/weakType.js
index 6ed3ff1814df9..5637271ccec3a 100644
--- a/tests/baselines/reference/weakType.js
+++ b/tests/baselines/reference/weakType.js
@@ -9,10 +9,14 @@ function getDefaultSettings() {
}
function doSomething(settings: Settings) { /* ... */ }
-
// forgot to call `getDefaultSettings`
// but it is not caught because we don't check for call signatures
doSomething(getDefaultSettings);
+// same for arrow expressions:
+doSomething(() => { });
+doSomething(12);
+doSomething('completely wrong');
+doSomething(false);
// this is an oddly popular way of defining settings
// this example is from services/textChanges.ts
@@ -65,6 +69,11 @@ function doSomething(settings) { }
// forgot to call `getDefaultSettings`
// but it is not caught because we don't check for call signatures
doSomething(getDefaultSettings);
+// same for arrow expressions:
+doSomething(function () { });
+doSomething(12);
+doSomething('completely wrong');
+doSomething(false);
function del(options, error) {
if (options === void 0) { options = {}; }
if (error === void 0) { error = {}; }
diff --git a/tests/cases/compiler/weakType.ts b/tests/cases/compiler/weakType.ts
index f04f36c9c2f9e..ffe51205e53c5 100644
--- a/tests/cases/compiler/weakType.ts
+++ b/tests/cases/compiler/weakType.ts
@@ -8,10 +8,14 @@ function getDefaultSettings() {
}
function doSomething(settings: Settings) { /* ... */ }
-
// forgot to call `getDefaultSettings`
// but it is not caught because we don't check for call signatures
doSomething(getDefaultSettings);
+// same for arrow expressions:
+doSomething(() => { });
+doSomething(12);
+doSomething('completely wrong');
+doSomething(false);
// this is an oddly popular way of defining settings
// this example is from services/textChanges.ts
diff --git a/tests/cases/conformance/jsx/tsxSpreadAttributesResolution1.tsx b/tests/cases/conformance/jsx/tsxSpreadAttributesResolution1.tsx
index 6d5225df2d902..a14a7ffe59c88 100644
--- a/tests/cases/conformance/jsx/tsxSpreadAttributesResolution1.tsx
+++ b/tests/cases/conformance/jsx/tsxSpreadAttributesResolution1.tsx
@@ -11,8 +11,8 @@ class Poisoned extends React.Component<{}, {}> {
}
}
-const obj: Object = {};
+const obj = {};
// OK
let p = <Poisoned {...obj} />;
-let y = <Poisoned />;
\ No newline at end of file
+let y = <Poisoned />;