Make type guard function types invariant in the type guarded for.

- Fix one break in the compiler. - Type guards like `isNetworked(): this is (Networked & this)` have been obsolete in favor of `isNetworked(): this is Networked` ever since narrowing was enhanced to take an intersection in a370908, and the first form now causes a problem: a subclass fails to be a subtype of its superclass because `this` appears in a non-covariant position. So replace all occurrences of the first form with the second form in the test suite. Fixes microsoft#26981.
mattmccutchen · Feb 10, 2019 · 07cf82a · 07cf82a
1 parent bbf559b
commit 07cf82a
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Showing 19 changed files with 274 additions and 223 deletions.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -11722,7 +11722,10 @@ namespace ts {
                 }
             }
 
-            const related = compareTypes(source.type, target.type, reportErrors);
+            let related = compareTypes(source.type, target.type, reportErrors);
+            if (related) {
+                related &= compareTypes(target.type, source.type, reportErrors);
+            }
             if (related === Ternary.False && reportErrors) {
                 errorReporter!(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typePredicateToString(source), typePredicateToString(target));
             }

diff --git a/src/services/documentHighlights.ts b/src/services/documentHighlights.ts
@@ -75,7 +75,7 @@ namespace ts.DocumentHighlights {
             case SyntaxKind.SetKeyword:
                 return getFromAllDeclarations(isAccessor, [SyntaxKind.GetKeyword, SyntaxKind.SetKeyword]);
             case SyntaxKind.AwaitKeyword:
-                return useParent(node.parent, isAwaitExpression, getAsyncAndAwaitOccurrences);
+                return useParent<AwaitExpression>(node.parent, isAwaitExpression, getAsyncAndAwaitOccurrences);
             case SyntaxKind.AsyncKeyword:
                 return highlightSpans(getAsyncAndAwaitOccurrences(node));
             case SyntaxKind.YieldKeyword:

diff --git a/tests/baselines/reference/typeGuardFunctionErrors.errors.txt b/tests/baselines/reference/typeGuardFunctionErrors.errors.txt
@@ -16,59 +16,62 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(41,56)
   Type 'number' is not assignable to type 'string'.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(45,56): error TS2677: A type predicate's type must be assignable to its parameter's type.
   Type 'T[]' is not assignable to type 'string'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(59,7): error TS2551: Property 'propB' does not exist on type 'A'. Did you mean 'propA'?
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(64,7): error TS2551: Property 'propB' does not exist on type 'A'. Did you mean 'propA'?
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(69,7): error TS2551: Property 'propB' does not exist on type 'A'. Did you mean 'propA'?
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(74,46): error TS2345: Argument of type '(p1: any) => p1 is C' is not assignable to parameter of type '(p1: any) => p1 is B'.
-  Type predicate 'p1 is C' is not assignable to 'p1 is B'.
-    Property 'propB' is missing in type 'C' but required in type 'B'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(78,1): error TS2322: Type '(p1: any, p2: any) => boolean' is not assignable to type '(p1: any, p2: any) => p1 is A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(60,7): error TS2551: Property 'propB' does not exist on type 'A'. Did you mean 'propA'?
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(65,7): error TS2551: Property 'propB' does not exist on type 'A'. Did you mean 'propA'?
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(70,7): error TS2551: Property 'propB' does not exist on type 'A'. Did you mean 'propA'?
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(75,46): error TS2345: Argument of type '(p1: any) => p1 is C' is not assignable to parameter of type '(p1: any) => p1 is A'.
+  Type predicate 'p1 is C' is not assignable to 'p1 is A'.
+    Property 'propC' is missing in type 'A' but required in type 'C'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(77,47): error TS2345: Argument of type '(p1: any) => p1 is A' is not assignable to parameter of type '(p1: any) => p1 is C'.
+  Type predicate 'p1 is A' is not assignable to 'p1 is C'.
+    Type 'A' is not assignable to type 'C'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(81,1): error TS2322: Type '(p1: any, p2: any) => boolean' is not assignable to type '(p1: any, p2: any) => p1 is A'.
   Signature '(p1: any, p2: any): boolean' must be a type predicate.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(84,1): error TS2322: Type '(p1: any, p2: any) => p2 is A' is not assignable to type '(p1: any, p2: any) => p1 is A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(87,1): error TS2322: Type '(p1: any, p2: any) => p2 is A' is not assignable to type '(p1: any, p2: any) => p1 is A'.
   Type predicate 'p2 is A' is not assignable to 'p1 is A'.
     Parameter 'p2' is not in the same position as parameter 'p1'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(90,1): error TS2322: Type '(p1: any, p2: any, p3: any) => p1 is A' is not assignable to type '(p1: any, p2: any) => p1 is A'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(95,9): error TS2304: Cannot find name 'b'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(95,11): error TS1005: ',' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(95,14): error TS1005: ',' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(95,14): error TS2300: Duplicate identifier 'A'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(96,16): error TS2304: Cannot find name 'b'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(96,18): error TS1005: ',' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(96,21): error TS1005: ',' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(97,20): error TS2304: Cannot find name 'b'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(97,22): error TS1144: '{' or ';' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(97,25): error TS1005: ';' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(97,27): error TS1005: ';' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(103,25): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(104,9): error TS2322: Type 'true' is not assignable to type 'D'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(104,9): error TS2409: Return type of constructor signature must be assignable to the instance type of the class.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(106,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(93,1): error TS2322: Type '(p1: any, p2: any, p3: any) => p1 is A' is not assignable to type '(p1: any, p2: any) => p1 is A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,9): error TS2304: Cannot find name 'b'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,11): error TS1005: ',' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,14): error TS1005: ',' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(98,14): error TS2300: Duplicate identifier 'A'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(99,16): error TS2304: Cannot find name 'b'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(99,18): error TS1005: ',' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(99,21): error TS1005: ',' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(100,20): error TS2304: Cannot find name 'b'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(100,22): error TS1144: '{' or ';' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(100,25): error TS1005: ';' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(100,27): error TS1005: ';' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(106,25): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(107,9): error TS2322: Type 'true' is not assignable to type 'D'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(107,9): error TS2409: Return type of constructor signature must be assignable to the instance type of the class.
 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(109,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(110,9): error TS2408: Setters cannot return a value.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(115,18): error TS1228: A type predicate is only allowed in return type position for functions and methods.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(119,22): error TS2304: Cannot find name 'p1'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(119,25): error TS1005: ';' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(119,28): error TS1005: ';' expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(120,1): error TS1128: Declaration or statement expected.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(123,20): error TS1229: A type predicate cannot reference a rest parameter.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(128,34): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(132,34): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(136,39): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(152,68): error TS2344: Type 'T | "d"' does not satisfy the constraint 'Keys'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(112,20): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(113,9): error TS2408: Setters cannot return a value.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(118,18): error TS1228: A type predicate is only allowed in return type position for functions and methods.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(122,22): error TS2304: Cannot find name 'p1'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(122,25): error TS1005: ';' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(122,28): error TS1005: ';' expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(123,1): error TS1128: Declaration or statement expected.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(126,20): error TS1229: A type predicate cannot reference a rest parameter.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(131,34): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(135,34): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(139,39): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(155,68): error TS2344: Type 'T | "d"' does not satisfy the constraint 'Keys'.
   Type '"d"' is not assignable to type 'Keys'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(159,31): error TS2344: Type 'Bar' does not satisfy the constraint 'Foo'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(162,31): error TS2344: Type 'Bar' does not satisfy the constraint 'Foo'.
   Types of property ''a'' are incompatible.
     Type 'number' is not assignable to type 'string'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(162,31): error TS2344: Type 'Bar' does not satisfy the constraint 'Foo'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(163,35): error TS2344: Type 'number' does not satisfy the constraint 'Foo'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(164,51): error TS2344: Type 'Bar' does not satisfy the constraint 'Foo'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(165,51): error TS2344: Type 'number' does not satisfy the constraint 'Foo'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(166,45): error TS2677: A type predicate's type must be assignable to its parameter's type.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(165,31): error TS2344: Type 'Bar' does not satisfy the constraint 'Foo'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(166,35): error TS2344: Type 'number' does not satisfy the constraint 'Foo'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(167,51): error TS2344: Type 'Bar' does not satisfy the constraint 'Foo'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(168,51): error TS2344: Type 'number' does not satisfy the constraint 'Foo'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(169,45): error TS2677: A type predicate's type must be assignable to its parameter's type.
   Type 'NeedsFoo<number>' is not assignable to type 'number'.
-tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(166,54): error TS2344: Type 'number' does not satisfy the constraint 'Foo'.
+tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(169,54): error TS2344: Type 'number' does not satisfy the constraint 'Foo'.
 
 
-==== tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts (56 errors) ====
+==== tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts (57 errors) ====
     class A {
           ~
 !!! error TS2300: Duplicate identifier 'A'.
@@ -154,6 +157,7 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(166,54
     let a: A;
     let b: B;
 
+    declare function isA(p1): p1 is A;
     declare function isB(p1): p1 is B;
     declare function isC(p1): p1 is C;
     declare function funA(p1: any, p2: any): p1 is B;
@@ -184,13 +188,19 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(166,54
     }
 
     // Type predicate type is not assignable
-    declare function acceptingDifferentSignatureTypeGuardFunction(p1: (p1) => p1 is B);
+    declare function acceptingDifferentSignatureTypeGuardFunction(p1: (p1) => p1 is A);
     acceptingDifferentSignatureTypeGuardFunction(isC);
                                                  ~~~
-!!! error TS2345: Argument of type '(p1: any) => p1 is C' is not assignable to parameter of type '(p1: any) => p1 is B'.
-!!! error TS2345:   Type predicate 'p1 is C' is not assignable to 'p1 is B'.
-!!! error TS2345:     Property 'propB' is missing in type 'C' but required in type 'B'.
-!!! related TS2728 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts:6:5: 'propB' is declared here.
+!!! error TS2345: Argument of type '(p1: any) => p1 is C' is not assignable to parameter of type '(p1: any) => p1 is A'.
+!!! error TS2345:   Type predicate 'p1 is C' is not assignable to 'p1 is A'.
+!!! error TS2345:     Property 'propC' is missing in type 'A' but required in type 'C'.
+!!! related TS2728 tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts:10:5: 'propC' is declared here.
+    declare function acceptingDifferentSignatureTypeGuardFunction2(p1: (p1) => p1 is C);
+    acceptingDifferentSignatureTypeGuardFunction2(isA);
+                                                  ~~~
+!!! error TS2345: Argument of type '(p1: any) => p1 is A' is not assignable to parameter of type '(p1: any) => p1 is C'.
+!!! error TS2345:   Type predicate 'p1 is A' is not assignable to 'p1 is C'.
+!!! error TS2345:     Type 'A' is not assignable to type 'C'.
 
     // Boolean not assignable to type guard
     var assign1: (p1, p2) => p1 is A;

diff --git a/tests/baselines/reference/typeGuardFunctionErrors.js b/tests/baselines/reference/typeGuardFunctionErrors.js
@@ -50,6 +50,7 @@ function hasNonMathcingGenericType<T>(a: string): a is T[] {
 let a: A;
 let b: B;
 
+declare function isA(p1): p1 is A;
 declare function isB(p1): p1 is B;
 declare function isC(p1): p1 is C;
 declare function funA(p1: any, p2: any): p1 is B;
@@ -71,8 +72,10 @@ if (hasNoTypeGuard(a)) {
 }
 
 // Type predicate type is not assignable
-declare function acceptingDifferentSignatureTypeGuardFunction(p1: (p1) => p1 is B);
+declare function acceptingDifferentSignatureTypeGuardFunction(p1: (p1) => p1 is A);
 acceptingDifferentSignatureTypeGuardFunction(isC);
+declare function acceptingDifferentSignatureTypeGuardFunction2(p1: (p1) => p1 is C);
+acceptingDifferentSignatureTypeGuardFunction2(isA);
 
 // Boolean not assignable to type guard
 var assign1: (p1, p2) => p1 is A;
@@ -240,6 +243,7 @@ if (hasNoTypeGuard(a)) {
     a.propB;
 }
 acceptingDifferentSignatureTypeGuardFunction(isC);
+acceptingDifferentSignatureTypeGuardFunction2(isA);
 // Boolean not assignable to type guard
 var assign1;
 assign1 = function (p1, p2) {