fix 61547

Author: HansBrende

src/compiler/checker.ts

@@ -25115,7 +25115,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         if (isReadonlySymbol(sourceProp) !== isReadonlySymbol(targetProp)) {
             return Ternary.False;
         }
-        return compareTypes(getTypeOfSymbol(sourceProp), getTypeOfSymbol(targetProp));
+        return compareTypes(getNonMissingTypeOfSymbol(sourceProp), getNonMissingTypeOfSymbol(targetProp));
     }
 
     function isMatchingSignature(source: Signature, target: Signature, partialMatch: boolean) {

tests/baselines/reference/exactOptionalPropertyTypesIdentical.errors.txt

@@ -0,0 +1,15 @@
+exactOptionalPropertyTypesIdentical.ts(2,12): error TS2322: Type '<T>() => T extends { a?: string; } ? 0 : 1' is not assignable to type '<T>() => T extends { a?: string | undefined; } ? 0 : 1'.
+  Type 'T extends { a?: string; } ? 0 : 1' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+    Type '0 | 1' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+      Type '0' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+
+
+==== exactOptionalPropertyTypesIdentical.ts (1 errors) ====
+    export let a: <T>() => T extends {a?: string} ? 0 : 1 = null!;
+    export let b: <T>() => T extends {a?: string | undefined} ? 0 : 1 = a;
+               ~
+!!! error TS2322: Type '<T>() => T extends { a?: string; } ? 0 : 1' is not assignable to type '<T>() => T extends { a?: string | undefined; } ? 0 : 1'.
+!!! error TS2322:   Type 'T extends { a?: string; } ? 0 : 1' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+!!! error TS2322:     Type '0 | 1' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+!!! error TS2322:       Type '0' is not assignable to type 'T extends { a?: string | undefined; } ? 0 : 1'.
+    

tests/baselines/reference/exactOptionalPropertyTypesIdentical.js

@@ -0,0 +1,13 @@
+//// [tests/cases/compiler/exactOptionalPropertyTypesIdentical.ts] ////
+
+//// [exactOptionalPropertyTypesIdentical.ts]
+export let a: <T>() => T extends {a?: string} ? 0 : 1 = null!;
+export let b: <T>() => T extends {a?: string | undefined} ? 0 : 1 = a;
+
+
+//// [exactOptionalPropertyTypesIdentical.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.b = exports.a = void 0;
+exports.a = null;
+exports.b = exports.a;

tests/baselines/reference/exactOptionalPropertyTypesIdentical.symbols

@@ -0,0 +1,16 @@
+//// [tests/cases/compiler/exactOptionalPropertyTypesIdentical.ts] ////
+
+=== exactOptionalPropertyTypesIdentical.ts ===
+export let a: <T>() => T extends {a?: string} ? 0 : 1 = null!;
+>a : Symbol(a, Decl(exactOptionalPropertyTypesIdentical.ts, 0, 10))
+>T : Symbol(T, Decl(exactOptionalPropertyTypesIdentical.ts, 0, 15))
+>T : Symbol(T, Decl(exactOptionalPropertyTypesIdentical.ts, 0, 15))
+>a : Symbol(a, Decl(exactOptionalPropertyTypesIdentical.ts, 0, 34))
+
+export let b: <T>() => T extends {a?: string | undefined} ? 0 : 1 = a;
+>b : Symbol(b, Decl(exactOptionalPropertyTypesIdentical.ts, 1, 10))
+>T : Symbol(T, Decl(exactOptionalPropertyTypesIdentical.ts, 1, 15))
+>T : Symbol(T, Decl(exactOptionalPropertyTypesIdentical.ts, 1, 15))
+>a : Symbol(a, Decl(exactOptionalPropertyTypesIdentical.ts, 1, 34))
+>a : Symbol(a, Decl(exactOptionalPropertyTypesIdentical.ts, 0, 10))
+

tests/baselines/reference/exactOptionalPropertyTypesIdentical.types

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/exactOptionalPropertyTypesIdentical.ts] ////
+
+=== exactOptionalPropertyTypesIdentical.ts ===
+export let a: <T>() => T extends {a?: string} ? 0 : 1 = null!;
+>a : <T>() => T extends { a?: string; } ? 0 : 1
+>  : ^ ^^^^^^^                                 
+>a : string | undefined
+>  : ^^^^^^^^^^^^^^^^^^
+>null! : never
+>      : ^^^^^
+
+export let b: <T>() => T extends {a?: string | undefined} ? 0 : 1 = a;
+>b : <T>() => T extends { a?: string | undefined; } ? 0 : 1
+>  : ^ ^^^^^^^                                             
+>a : string | undefined
+>  : ^^^^^^^^^^^^^^^^^^
+>a : <T>() => T extends { a?: string; } ? 0 : 1
+>  : ^ ^^^^^^^                                 
+

tests/cases/compiler/exactOptionalPropertyTypesIdentical.ts

@@ -0,0 +1,5 @@
+// @strictNullChecks: true
+// @exactOptionalPropertyTypes: true
+
+export let a: <T>() => T extends {a?: string} ? 0 : 1 = null!;
+export let b: <T>() => T extends {a?: string | undefined} ? 0 : 1 = a;