Add return type specialized message

Author: weswigham

src/compiler/checker.ts

@@ -12827,7 +12827,11 @@ namespace ts {
                     }
                 }
                 if (path) {
-                    reportError(Diagnostics.The_types_of_0_are_incompatible_between_these_types, path);
+                    reportError(path[path.length - 1] === ")"
+                        ? Diagnostics.The_types_returned_by_0_are_incompatible_between_these_types
+                        : Diagnostics.The_types_of_0_are_incompatible_between_these_types,
+                        path
+                    );
                 }
                 else {
                     // Remove the innermost secondary error as it will duplicate the error already reported by `reportRelationError` on entry

src/compiler/diagnosticMessages.json

@@ -1044,24 +1044,28 @@
         "category": "Error",
         "code": 2200
     },
+    "The types returned by '{0}' are incompatible between these types.": {
+        "category": "Error",
+        "code": 2201
+    },
     "Call signature return types '{0}' and '{1}' are incompatible.": {
         "category": "Error",
-        "code": 2201,
+        "code": 2202,
         "elidedInCompatabilityPyramid": true
     },
     "Construct signature return types '{0}' and '{1}' are incompatible.": {
         "category": "Error",
-        "code": 2202,
+        "code": 2203,
         "elidedInCompatabilityPyramid": true
     },
     "Call signatures with no arguments have incompatible return types '{0}' and '{1}'.": {
         "category": "Error",
-        "code": 2203,
+        "code": 2204,
         "elidedInCompatabilityPyramid": true
     },
     "Construct signatures with no arguments have incompatible return types '{0}' and '{1}'.": {
         "category": "Error",
-        "code": 2204,
+        "code": 2205,
         "elidedInCompatabilityPyramid": true
     },
 

tests/baselines/reference/arrayLiterals3.errors.txt

@@ -8,7 +8,7 @@ tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(17,5): error
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(32,5): error TS2739: Type '(number[] | string[])[]' is missing the following properties from type 'tup': 0, 1
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(33,5): error TS2739: Type 'number[]' is missing the following properties from type '[number, number, number]': 0, 1, 2
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(34,5): error TS2322: Type '(string | number)[]' is not assignable to type 'myArray'.
-  The types of 'pop()' are incompatible between these types.
+  The types returned by 'pop()' are incompatible between these types.
     Type 'string | number' is not assignable to type 'Number'.
       Type 'string' is not assignable to type 'Number'.
 
@@ -66,7 +66,7 @@ tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(34,5): error
     var c2: myArray = [...temp1, ...temp];            // Error cannot assign (number|string)[] to number[]
         ~~
 !!! error TS2322: Type '(string | number)[]' is not assignable to type 'myArray'.
-!!! error TS2322:   The types of 'pop()' are incompatible between these types.
+!!! error TS2322:   The types returned by 'pop()' are incompatible between these types.
 !!! error TS2322:     Type 'string | number' is not assignable to type 'Number'.
 !!! error TS2322:       Type 'string' is not assignable to type 'Number'.
 

tests/baselines/reference/arrayOfSubtypeIsAssignableToReadonlyArray.errors.txt

@@ -1,7 +1,7 @@
 tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(13,1): error TS2322: Type 'A[]' is not assignable to type 'readonly B[]'.
   Property 'b' is missing in type 'A' but required in type 'B'.
 tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(18,1): error TS2322: Type 'C<A>' is not assignable to type 'readonly B[]'.
-  The types of 'concat(...)' are incompatible between these types.
+  The types returned by 'concat(...)' are incompatible between these types.
     Type 'A[]' is not assignable to type 'B[]'.
       Type 'A' is not assignable to type 'B'.
 
@@ -31,7 +31,7 @@ tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(18,1): error T
     rrb = cra; // error: 'A' is not assignable to 'B'
     ~~~
 !!! error TS2322: Type 'C<A>' is not assignable to type 'readonly B[]'.
-!!! error TS2322:   The types of 'concat(...)' are incompatible between these types.
+!!! error TS2322:   The types returned by 'concat(...)' are incompatible between these types.
 !!! error TS2322:     Type 'A[]' is not assignable to type 'B[]'.
 !!! error TS2322:       Type 'A' is not assignable to type 'B'.
 

tests/baselines/reference/assignFromBooleanInterface2.errors.txt

@@ -1,5 +1,5 @@
 tests/cases/conformance/types/primitives/boolean/assignFromBooleanInterface2.ts(14,1): error TS2322: Type 'NotBoolean' is not assignable to type 'Boolean'.
-  The types of 'valueOf()' are incompatible between these types.
+  The types returned by 'valueOf()' are incompatible between these types.
     Type 'Object' is not assignable to type 'boolean'.
 tests/cases/conformance/types/primitives/boolean/assignFromBooleanInterface2.ts(19,1): error TS2322: Type 'Boolean' is not assignable to type 'boolean'.
   'boolean' is a primitive, but 'Boolean' is a wrapper object. Prefer using 'boolean' when possible.
@@ -23,7 +23,7 @@ tests/cases/conformance/types/primitives/boolean/assignFromBooleanInterface2.ts(
     a = b;
     ~
 !!! error TS2322: Type 'NotBoolean' is not assignable to type 'Boolean'.
-!!! error TS2322:   The types of 'valueOf()' are incompatible between these types.
+!!! error TS2322:   The types returned by 'valueOf()' are incompatible between these types.
 !!! error TS2322:     Type 'Object' is not assignable to type 'boolean'.
 
     b = a;

tests/baselines/reference/asyncFunctionDeclaration15_es5.errors.txt

@@ -6,7 +6,7 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration1
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(9,23): error TS1055: Type 'PromiseLike' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
   Construct signature return types 'Thenable' and 'PromiseLike<T>' are incompatible.
-    The types of 'then(...)' are incompatible between these types.
+    The types returned by 'then(...)' are incompatible between these types.
       Type 'void' is not assignable to type 'PromiseLike<TResult1 | TResult2>'.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(17,16): error TS1058: The return type of an async function must either be a valid promise or must not contain a callable 'then' member.
 tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(23,25): error TS1320: Type of 'await' operand must either be a valid promise or must not contain a callable 'then' member.
@@ -38,7 +38,7 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration1
                           ~~~~~~~~
 !!! error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
 !!! error TS1055:   Construct signature return types 'Thenable' and 'PromiseLike<T>' are incompatible.
-!!! error TS1055:     The types of 'then(...)' are incompatible between these types.
+!!! error TS1055:     The types returned by 'then(...)' are incompatible between these types.
 !!! error TS1055:       Type 'void' is not assignable to type 'PromiseLike<TResult1 | TResult2>'.
     async function fn7() { return; } // valid: Promise<void>
     async function fn8() { return 1; } // valid: Promise<number>

tests/baselines/reference/bigintWithLib.errors.txt

@@ -4,7 +4,7 @@ tests/cases/compiler/bigintWithLib.ts(16,33): error TS2769: No overload matches
     Argument of type 'number[]' is not assignable to parameter of type 'number'.
   Overload 2 of 3, '(array: Iterable<bigint>): BigInt64Array', gave the following error.
     Argument of type 'number[]' is not assignable to parameter of type 'Iterable<bigint>'.
-      The types of '[Symbol.iterator]().next(...)' are incompatible between these types.
+      The types returned by '[Symbol.iterator]().next(...)' are incompatible between these types.
         Type 'IteratorResult<number, any>' is not assignable to type 'IteratorResult<bigint, any>'.
           Type 'IteratorYieldResult<number>' is not assignable to type 'IteratorResult<bigint, any>'.
             Type 'IteratorYieldResult<number>' is not assignable to type 'IteratorYieldResult<bigint>'.
@@ -51,7 +51,7 @@ tests/cases/compiler/bigintWithLib.ts(43,26): error TS2345: Argument of type '12
 !!! error TS2769:     Argument of type 'number[]' is not assignable to parameter of type 'number'.
 !!! error TS2769:   Overload 2 of 3, '(array: Iterable<bigint>): BigInt64Array', gave the following error.
 !!! error TS2769:     Argument of type 'number[]' is not assignable to parameter of type 'Iterable<bigint>'.
-!!! error TS2769:       The types of '[Symbol.iterator]().next(...)' are incompatible between these types.
+!!! error TS2769:       The types returned by '[Symbol.iterator]().next(...)' are incompatible between these types.
 !!! error TS2769:         Type 'IteratorResult<number, any>' is not assignable to type 'IteratorResult<bigint, any>'.
 !!! error TS2769:           Type 'IteratorYieldResult<number>' is not assignable to type 'IteratorResult<bigint, any>'.
 !!! error TS2769:             Type 'IteratorYieldResult<number>' is not assignable to type 'IteratorYieldResult<bigint>'.

tests/baselines/reference/booleanAssignment.errors.txt

@@ -1,7 +1,7 @@
 tests/cases/compiler/booleanAssignment.ts(2,1): error TS2322: Type '1' is not assignable to type 'Boolean'.
 tests/cases/compiler/booleanAssignment.ts(3,1): error TS2322: Type '"a"' is not assignable to type 'Boolean'.
 tests/cases/compiler/booleanAssignment.ts(4,1): error TS2322: Type '{}' is not assignable to type 'Boolean'.
-  The types of 'valueOf()' are incompatible between these types.
+  The types returned by 'valueOf()' are incompatible between these types.
     Type 'Object' is not assignable to type 'boolean'.
 
 
@@ -16,7 +16,7 @@ tests/cases/compiler/booleanAssignment.ts(4,1): error TS2322: Type '{}' is not a
     b = {}; // Error
     ~
 !!! error TS2322: Type '{}' is not assignable to type 'Boolean'.
-!!! error TS2322:   The types of 'valueOf()' are incompatible between these types.
+!!! error TS2322:   The types returned by 'valueOf()' are incompatible between these types.
 !!! error TS2322:     Type 'Object' is not assignable to type 'boolean'.
 
     var o = {};

tests/baselines/reference/callSignatureAssignabilityInInheritance.errors.txt

@@ -1,8 +1,8 @@
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSignatureAssignabilityInInheritance.ts(57,15): error TS2430: Interface 'I2' incorrectly extends interface 'Base2'.
-  The types of 'a(...)' are incompatible between these types.
+  The types returned by 'a(...)' are incompatible between these types.
     Type 'string' is not assignable to type 'number'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSignatureAssignabilityInInheritance.ts(63,15): error TS2430: Interface 'I3' incorrectly extends interface 'Base2'.
-  The types of 'a2(...)' are incompatible between these types.
+  The types returned by 'a2(...)' are incompatible between these types.
     Type 'string' is not assignable to type 'T'.
       'string' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '{}'.
 
@@ -67,7 +67,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSign
         interface I2 extends Base2 {
                   ~~
 !!! error TS2430: Interface 'I2' incorrectly extends interface 'Base2'.
-!!! error TS2430:   The types of 'a(...)' are incompatible between these types.
+!!! error TS2430:   The types returned by 'a(...)' are incompatible between these types.
 !!! error TS2430:     Type 'string' is not assignable to type 'number'.
             // N's
             a: (x: number) => string; // error because base returns non-void;
@@ -77,7 +77,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSign
         interface I3 extends Base2 {
                   ~~
 !!! error TS2430: Interface 'I3' incorrectly extends interface 'Base2'.
-!!! error TS2430:   The types of 'a2(...)' are incompatible between these types.
+!!! error TS2430:   The types returned by 'a2(...)' are incompatible between these types.
 !!! error TS2430:     Type 'string' is not assignable to type 'T'.
 !!! error TS2430:       'string' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '{}'.
             // N's

tests/baselines/reference/callSignatureAssignabilityInInheritance3.errors.txt

@@ -27,12 +27,12 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSign
           Types of property 'a' are incompatible.
             Type 'string' is not assignable to type 'Base'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSignatureAssignabilityInInheritance3.ts(100,19): error TS2430: Interface 'I6' incorrectly extends interface 'B'.
-  The types of 'a2(...)' are incompatible between these types.
+  The types returned by 'a2(...)' are incompatible between these types.
     Type 'string[]' is not assignable to type 'T[]'.
       Type 'string' is not assignable to type 'T'.
         'string' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '{}'.
 tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSignatureAssignabilityInInheritance3.ts(109,19): error TS2430: Interface 'I7' incorrectly extends interface 'C'.
-  The types of 'a2(...)' are incompatible between these types.
+  The types returned by 'a2(...)' are incompatible between these types.
     Type 'T[]' is not assignable to type 'string[]'.
       Type 'T' is not assignable to type 'string'.
 
@@ -172,7 +172,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSign
             interface I6 extends B {
                       ~~
 !!! error TS2430: Interface 'I6' incorrectly extends interface 'B'.
-!!! error TS2430:   The types of 'a2(...)' are incompatible between these types.
+!!! error TS2430:   The types returned by 'a2(...)' are incompatible between these types.
 !!! error TS2430:     Type 'string[]' is not assignable to type 'T[]'.
 !!! error TS2430:       Type 'string' is not assignable to type 'T'.
 !!! error TS2430:         'string' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '{}'.
@@ -187,7 +187,7 @@ tests/cases/conformance/types/typeRelationships/assignmentCompatibility/callSign
             interface I7 extends C {
                       ~~
 !!! error TS2430: Interface 'I7' incorrectly extends interface 'C'.
-!!! error TS2430:   The types of 'a2(...)' are incompatible between these types.
+!!! error TS2430:   The types returned by 'a2(...)' are incompatible between these types.
 !!! error TS2430:     Type 'T[]' is not assignable to type 'string[]'.
 !!! error TS2430:       Type 'T' is not assignable to type 'string'.
                 a2: <T>(x: T) => T[]; // error

tests/baselines/reference/complexRecursiveCollections.errors.txt

@@ -1,13 +1,13 @@
 tests/cases/compiler/immutable.ts(341,22): error TS2430: Interface 'Keyed<K, V>' incorrectly extends interface 'Collection<K, V>'.
-  The types of 'toSeq()' are incompatible between these types.
+  The types returned by 'toSeq()' are incompatible between these types.
     Type 'Keyed<K, V>' is not assignable to type 'this'.
       'Keyed<K, V>' is assignable to the constraint of type 'this', but 'this' could be instantiated with a different subtype of constraint 'Keyed<K, V>'.
 tests/cases/compiler/immutable.ts(359,22): error TS2430: Interface 'Indexed<T>' incorrectly extends interface 'Collection<number, T>'.
-  The types of 'toSeq()' are incompatible between these types.
+  The types returned by 'toSeq()' are incompatible between these types.
     Type 'Indexed<T>' is not assignable to type 'this'.
       'Indexed<T>' is assignable to the constraint of type 'this', but 'this' could be instantiated with a different subtype of constraint 'Indexed<T>'.
 tests/cases/compiler/immutable.ts(391,22): error TS2430: Interface 'Set<T>' incorrectly extends interface 'Collection<never, T>'.
-  The types of 'toSeq()' are incompatible between these types.
+  The types returned by 'toSeq()' are incompatible between these types.
     Type 'Set<T>' is not assignable to type 'this'.
       'Set<T>' is assignable to the constraint of type 'this', but 'this' could be instantiated with a different subtype of constraint 'Set<T>'.
 
@@ -377,7 +377,7 @@ tests/cases/compiler/immutable.ts(391,22): error TS2430: Interface 'Set<T>' inco
         export interface Keyed<K, V> extends Collection<K, V> {
                          ~~~~~
 !!! error TS2430: Interface 'Keyed<K, V>' incorrectly extends interface 'Collection<K, V>'.
-!!! error TS2430:   The types of 'toSeq()' are incompatible between these types.
+!!! error TS2430:   The types returned by 'toSeq()' are incompatible between these types.
 !!! error TS2430:     Type 'Keyed<K, V>' is not assignable to type 'this'.
 !!! error TS2430:       'Keyed<K, V>' is assignable to the constraint of type 'this', but 'this' could be instantiated with a different subtype of constraint 'Keyed<K, V>'.
           toJS(): Object;
@@ -400,7 +400,7 @@ tests/cases/compiler/immutable.ts(391,22): error TS2430: Interface 'Set<T>' inco
         export interface Indexed<T> extends Collection<number, T> {
                          ~~~~~~~
 !!! error TS2430: Interface 'Indexed<T>' incorrectly extends interface 'Collection<number, T>'.
-!!! error TS2430:   The types of 'toSeq()' are incompatible between these types.
+!!! error TS2430:   The types returned by 'toSeq()' are incompatible between these types.
 !!! error TS2430:     Type 'Indexed<T>' is not assignable to type 'this'.
 !!! error TS2430:       'Indexed<T>' is assignable to the constraint of type 'this', but 'this' could be instantiated with a different subtype of constraint 'Indexed<T>'.
           toJS(): Array<any>;
@@ -437,7 +437,7 @@ tests/cases/compiler/immutable.ts(391,22): error TS2430: Interface 'Set<T>' inco
         export interface Set<T> extends Collection<never, T> {
                          ~~~
 !!! error TS2430: Interface 'Set<T>' incorrectly extends interface 'Collection<never, T>'.
-!!! error TS2430:   The types of 'toSeq()' are incompatible between these types.
+!!! error TS2430:   The types returned by 'toSeq()' are incompatible between these types.
 !!! error TS2430:     Type 'Set<T>' is not assignable to type 'this'.
 !!! error TS2430:       'Set<T>' is assignable to the constraint of type 'this', but 'this' could be instantiated with a different subtype of constraint 'Set<T>'.
           toJS(): Array<any>;