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preserve some old behavior at @DanielRosenwassers request

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This commit is contained in:
Wesley Wigham 2015-12-08 17:45:11 -08:00
parent 459430165d
commit 0228ec3ced
3 changed files with 20 additions and 2 deletions
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10
src/compiler/checker.ts
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@ -5633,6 +5633,16 @@ namespace ts {
if (targetReturnType === voidType) return result;
const sourceReturnType = getReturnTypeOfSignature(source);
// The follow block preserves old behavior forbidding boolean returning functions from being assignable to type guard returning functions
if (targetReturnType.flags & TypeFlags.PredicateType && (targetReturnType as PredicateType).predicate.kind === TypePredicateKind.Identifier) {
if (!(sourceReturnType.flags & TypeFlags.PredicateType)) {
if (reportErrors) {
reportError(Diagnostics.Signature_0_must_have_a_type_predicate, signatureToString(source));
}
return Ternary.False;
}
}
return result & isRelatedTo(sourceReturnType, targetReturnType, reportErrors);
}

5
tests/baselines/reference/stringLiteralTypesAsTags01.errors.txt
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@ -1,7 +1,8 @@
tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTags01.ts(20,10): error TS2394: Overload signature is not compatible with function implementation.
tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTags01.ts(22,21): error TS2304: Cannot find name 'is'.
==== tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTags01.ts (1 errors) ====
==== tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTags01.ts (2 errors) ====
type Kind = "A" | "B"
@ -22,6 +23,8 @@ tests/cases/conformance/types/stringLiteral/stringLiteralTypesAsTags01.ts(22,21)
function hasKind(entity: Entity, kind: "A"): entity is A;
function hasKind(entity: Entity, kind: "B"): entity is B;
function hasKind(entity: Entity, kind: Kind): entity is Entity;
~~~~~~~
!!! error TS2394: Overload signature is not compatible with function implementation.
function hasKind(entity: Entity, kind: Kind): boolean {
return kind === is;
~~

7
tests/baselines/reference/typeGuardFunctionErrors.errors.txt
View File

@ -17,6 +17,8 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(75,46)
Type predicate 'p1 is C' is not assignable to 'p1 is B'.
Type 'C' is not assignable to type 'B'.
Property 'propB' is missing in type 'C'.
tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(79,1): 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 have a type predicate.
tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(85,1): 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'.
@ -39,7 +41,7 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(133,34
tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(137,39): error TS1230: A type predicate cannot reference element 'p1' in a binding pattern.
==== tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts (32 errors) ====
==== tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts (33 errors) ====
class A {
propA: number;
@ -153,6 +155,9 @@ tests/cases/conformance/expressions/typeGuards/typeGuardFunctionErrors.ts(137,39
// Boolean not assignable to type guard
var assign1: (p1, p2) => p1 is A;
assign1 = function(p1, p2): boolean {
~~~~~~~
!!! error TS2322: Type '(p1: any, p2: any) => boolean' is not assignable to type '(p1: any, p2: any) => p1 is A'.
!!! error TS2322: Signature '(p1: any, p2: any): boolean' must have a type predicate.
return true;
};