Compare optional property flag when comparing against discriminant properties under exactOptionalPropertyTypes

src/compiler/checker.ts

@@ -24166,7 +24166,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                         if (!targetProperty) continue outer;
                         if (sourceProperty === targetProperty) continue;
                         // We compare the source property to the target in the context of a single discriminant type.
-                        const related = propertyRelatedTo(source, target, sourceProperty, targetProperty, _ => combination[i], /*reportErrors*/ false, IntersectionState.None, /*skipOptional*/ strictNullChecks || relation === comparableRelation);
+                        const related = propertyRelatedTo(source, target, sourceProperty, targetProperty, _ => combination[i], /*reportErrors*/ false, IntersectionState.None, /*skipOptional*/ strictNullChecks && !exactOptionalPropertyTypes || relation === comparableRelation);
                         // If the target property could not be found, or if the properties were not related,
                         // then this constituent is not a match.
                         if (!related) {

tests/baselines/reference/unionRelationshipCheckPasses2(exactoptionalpropertytypes=false).errors.txt

@@ -0,0 +1,46 @@
+unionRelationshipCheckPasses2.ts(10,3): error TS2322: Type '{ type: "A"; value?: undefined; } | { type: "B"; value: string; }' is not assignable to type 'U'.
+  Type '{ type: "A"; value?: undefined; }' is not assignable to type 'U'.
+    Type '{ type: "A"; value?: undefined; }' is not assignable to type '{ type: "A"; value: null; }'.
+      Types of property 'value' are incompatible.
+        Type 'undefined' is not assignable to type 'null'.
+unionRelationshipCheckPasses2.ts(21,5): error TS2322: Type '{ type: "A"; }' is not assignable to type 'U'.
+  Property 'value' is missing in type '{ type: "A"; }' but required in type '{ type: "A"; value: null; }'.
+
+
+==== unionRelationshipCheckPasses2.ts (2 errors) ====
+    // https://github.com/microsoft/TypeScript/issues/61678
+
+    export type U = { type: "A"; value: null } | { type: "B"; value: string };
+
+    function call<T>(f: () => T): T {
+      return f();
+    }
+
+    export function functionCall(): U {
+      return call(() => {  // error
+      ~~~~~~
+!!! error TS2322: Type '{ type: "A"; value?: undefined; } | { type: "B"; value: string; }' is not assignable to type 'U'.
+!!! error TS2322:   Type '{ type: "A"; value?: undefined; }' is not assignable to type 'U'.
+!!! error TS2322:     Type '{ type: "A"; value?: undefined; }' is not assignable to type '{ type: "A"; value: null; }'.
+!!! error TS2322:       Types of property 'value' are incompatible.
+!!! error TS2322:         Type 'undefined' is not assignable to type 'null'.
+        if (Math.random()) {
+          return { type: "A" };
+        }
+
+        return { type: "B", value: "test" };
+      });
+    }
+
+    export function directReturn(): U {
+      if (Math.random()) {
+        return { type: "A" }; // error
+        ~~~~~~
+!!! error TS2322: Type '{ type: "A"; }' is not assignable to type 'U'.
+!!! error TS2322:   Property 'value' is missing in type '{ type: "A"; }' but required in type '{ type: "A"; value: null; }'.
+!!! related TS2728 unionRelationshipCheckPasses2.ts:3:30: 'value' is declared here.
+      }
+
+      return { type: "B", value: "test" };
+    }
+

tests/baselines/reference/unionRelationshipCheckPasses2(exactoptionalpropertytypes=false).symbols

@@ -0,0 +1,64 @@
+//// [tests/cases/compiler/unionRelationshipCheckPasses2.ts] ////
+
+=== unionRelationshipCheckPasses2.ts ===
+// https://github.com/microsoft/TypeScript/issues/61678
+
+export type U = { type: "A"; value: null } | { type: "B"; value: string };
+>U : Symbol(U, Decl(unionRelationshipCheckPasses2.ts, 0, 0))
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 2, 17))
+>value : Symbol(value, Decl(unionRelationshipCheckPasses2.ts, 2, 28))
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 2, 46))
+>value : Symbol(value, Decl(unionRelationshipCheckPasses2.ts, 2, 57))
+
+function call<T>(f: () => T): T {
+>call : Symbol(call, Decl(unionRelationshipCheckPasses2.ts, 2, 74))
+>T : Symbol(T, Decl(unionRelationshipCheckPasses2.ts, 4, 14))
+>f : Symbol(f, Decl(unionRelationshipCheckPasses2.ts, 4, 17))
+>T : Symbol(T, Decl(unionRelationshipCheckPasses2.ts, 4, 14))
+>T : Symbol(T, Decl(unionRelationshipCheckPasses2.ts, 4, 14))
+
+  return f();
+>f : Symbol(f, Decl(unionRelationshipCheckPasses2.ts, 4, 17))
+}
+
+export function functionCall(): U {
+>functionCall : Symbol(functionCall, Decl(unionRelationshipCheckPasses2.ts, 6, 1))
+>U : Symbol(U, Decl(unionRelationshipCheckPasses2.ts, 0, 0))
+
+  return call(() => {  // error
+>call : Symbol(call, Decl(unionRelationshipCheckPasses2.ts, 2, 74))
+
+    if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
+
+      return { type: "A" };
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 11, 14))
+    }
+
+    return { type: "B", value: "test" };
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 14, 12))
+>value : Symbol(value, Decl(unionRelationshipCheckPasses2.ts, 14, 23))
+
+  });
+}
+
+export function directReturn(): U {
+>directReturn : Symbol(directReturn, Decl(unionRelationshipCheckPasses2.ts, 16, 1))
+>U : Symbol(U, Decl(unionRelationshipCheckPasses2.ts, 0, 0))
+
+  if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
+
+    return { type: "A" }; // error
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 20, 12))
+  }
+
+  return { type: "B", value: "test" };
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 23, 10))
+>value : Symbol(value, Decl(unionRelationshipCheckPasses2.ts, 23, 21))
+}
+

tests/baselines/reference/unionRelationshipCheckPasses2(exactoptionalpropertytypes=false).types

@@ -0,0 +1,112 @@
+//// [tests/cases/compiler/unionRelationshipCheckPasses2.ts] ////
+
+=== unionRelationshipCheckPasses2.ts ===
+// https://github.com/microsoft/TypeScript/issues/61678
+
+export type U = { type: "A"; value: null } | { type: "B"; value: string };
+>U : U
+>  : ^
+>type : "A"
+>     : ^^^
+>value : null
+>      : ^^^^
+>type : "B"
+>     : ^^^
+>value : string
+>      : ^^^^^^
+
+function call<T>(f: () => T): T {
+>call : <T>(f: () => T) => T
+>     : ^ ^^ ^^       ^^^^^ 
+>f : () => T
+>  : ^^^^^^ 
+
+  return f();
+>f() : T
+>    : ^
+>f : () => T
+>  : ^^^^^^ 
+}
+
+export function functionCall(): U {
+>functionCall : () => U
+>             : ^^^^^^ 
+
+  return call(() => {  // error
+>call(() => {  // error    if (Math.random()) {      return { type: "A" };    }    return { type: "B", value: "test" };  }) : { type: "A"; value?: undefined; } | { type: "B"; value: string; }
+>                                                                                                                           : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>call : <T>(f: () => T) => T
+>     : ^ ^^ ^^       ^^^^^ 
+>() => {  // error    if (Math.random()) {      return { type: "A" };    }    return { type: "B", value: "test" };  } : () => { type: "A"; value?: undefined; } | { type: "B"; value: string; }
+>                                                                                                                     : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+    if (Math.random()) {
+>Math.random() : number
+>              : ^^^^^^
+>Math.random : () => number
+>            : ^^^^^^      
+>Math : Math
+>     : ^^^^
+>random : () => number
+>       : ^^^^^^      
+
+      return { type: "A" };
+>{ type: "A" } : { type: "A"; }
+>              : ^^^^^^^^^^^^^^
+>type : "A"
+>     : ^^^
+>"A" : "A"
+>    : ^^^
+    }
+
+    return { type: "B", value: "test" };
+>{ type: "B", value: "test" } : { type: "B"; value: string; }
+>                             : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>type : "B"
+>     : ^^^
+>"B" : "B"
+>    : ^^^
+>value : string
+>      : ^^^^^^
+>"test" : "test"
+>       : ^^^^^^
+
+  });
+}
+
+export function directReturn(): U {
+>directReturn : () => U
+>             : ^^^^^^ 
+
+  if (Math.random()) {
+>Math.random() : number
+>              : ^^^^^^
+>Math.random : () => number
+>            : ^^^^^^      
+>Math : Math
+>     : ^^^^
+>random : () => number
+>       : ^^^^^^      
+
+    return { type: "A" }; // error
+>{ type: "A" } : { type: "A"; }
+>              : ^^^^^^^^^^^^^^
+>type : "A"
+>     : ^^^
+>"A" : "A"
+>    : ^^^
+  }
+
+  return { type: "B", value: "test" };
+>{ type: "B", value: "test" } : { type: "B"; value: string; }
+>                             : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>type : "B"
+>     : ^^^
+>"B" : "B"
+>    : ^^^
+>value : string
+>      : ^^^^^^
+>"test" : "test"
+>       : ^^^^^^
+}
+

tests/baselines/reference/unionRelationshipCheckPasses2(exactoptionalpropertytypes=true).errors.txt

@@ -0,0 +1,44 @@
+unionRelationshipCheckPasses2.ts(10,3): error TS2322: Type '{ type: "A"; value?: never; } | { type: "B"; value: string; }' is not assignable to type 'U'.
+  Type '{ type: "A"; value?: never; }' is not assignable to type 'U'.
+    Type '{ type: "A"; value?: never; }' is not assignable to type '{ type: "A"; value: null; }'.
+      Property 'value' is optional in type '{ type: "A"; value?: never; }' but required in type '{ type: "A"; value: null; }'.
+unionRelationshipCheckPasses2.ts(21,5): error TS2322: Type '{ type: "A"; }' is not assignable to type 'U'.
+  Property 'value' is missing in type '{ type: "A"; }' but required in type '{ type: "A"; value: null; }'.
+
+
+==== unionRelationshipCheckPasses2.ts (2 errors) ====
+    // https://github.com/microsoft/TypeScript/issues/61678
+
+    export type U = { type: "A"; value: null } | { type: "B"; value: string };
+
+    function call<T>(f: () => T): T {
+      return f();
+    }
+
+    export function functionCall(): U {
+      return call(() => {  // error
+      ~~~~~~
+!!! error TS2322: Type '{ type: "A"; value?: never; } | { type: "B"; value: string; }' is not assignable to type 'U'.
+!!! error TS2322:   Type '{ type: "A"; value?: never; }' is not assignable to type 'U'.
+!!! error TS2322:     Type '{ type: "A"; value?: never; }' is not assignable to type '{ type: "A"; value: null; }'.
+!!! error TS2322:       Property 'value' is optional in type '{ type: "A"; value?: never; }' but required in type '{ type: "A"; value: null; }'.
+        if (Math.random()) {
+          return { type: "A" };
+        }
+
+        return { type: "B", value: "test" };
+      });
+    }
+
+    export function directReturn(): U {
+      if (Math.random()) {
+        return { type: "A" }; // error
+        ~~~~~~
+!!! error TS2322: Type '{ type: "A"; }' is not assignable to type 'U'.
+!!! error TS2322:   Property 'value' is missing in type '{ type: "A"; }' but required in type '{ type: "A"; value: null; }'.
+!!! related TS2728 unionRelationshipCheckPasses2.ts:3:30: 'value' is declared here.
+      }
+
+      return { type: "B", value: "test" };
+    }
+

tests/baselines/reference/unionRelationshipCheckPasses2(exactoptionalpropertytypes=true).symbols

@@ -0,0 +1,64 @@
+//// [tests/cases/compiler/unionRelationshipCheckPasses2.ts] ////
+
+=== unionRelationshipCheckPasses2.ts ===
+// https://github.com/microsoft/TypeScript/issues/61678
+
+export type U = { type: "A"; value: null } | { type: "B"; value: string };
+>U : Symbol(U, Decl(unionRelationshipCheckPasses2.ts, 0, 0))
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 2, 17))
+>value : Symbol(value, Decl(unionRelationshipCheckPasses2.ts, 2, 28))
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 2, 46))
+>value : Symbol(value, Decl(unionRelationshipCheckPasses2.ts, 2, 57))
+
+function call<T>(f: () => T): T {
+>call : Symbol(call, Decl(unionRelationshipCheckPasses2.ts, 2, 74))
+>T : Symbol(T, Decl(unionRelationshipCheckPasses2.ts, 4, 14))
+>f : Symbol(f, Decl(unionRelationshipCheckPasses2.ts, 4, 17))
+>T : Symbol(T, Decl(unionRelationshipCheckPasses2.ts, 4, 14))
+>T : Symbol(T, Decl(unionRelationshipCheckPasses2.ts, 4, 14))
+
+  return f();
+>f : Symbol(f, Decl(unionRelationshipCheckPasses2.ts, 4, 17))
+}
+
+export function functionCall(): U {
+>functionCall : Symbol(functionCall, Decl(unionRelationshipCheckPasses2.ts, 6, 1))
+>U : Symbol(U, Decl(unionRelationshipCheckPasses2.ts, 0, 0))
+
+  return call(() => {  // error
+>call : Symbol(call, Decl(unionRelationshipCheckPasses2.ts, 2, 74))
+
+    if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
+
+      return { type: "A" };
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 11, 14))
+    }
+
+    return { type: "B", value: "test" };
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 14, 12))
+>value : Symbol(value, Decl(unionRelationshipCheckPasses2.ts, 14, 23))
+
+  });
+}
+
+export function directReturn(): U {
+>directReturn : Symbol(directReturn, Decl(unionRelationshipCheckPasses2.ts, 16, 1))
+>U : Symbol(U, Decl(unionRelationshipCheckPasses2.ts, 0, 0))
+
+  if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --))
+
+    return { type: "A" }; // error
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 20, 12))
+  }
+
+  return { type: "B", value: "test" };
+>type : Symbol(type, Decl(unionRelationshipCheckPasses2.ts, 23, 10))
+>value : Symbol(value, Decl(unionRelationshipCheckPasses2.ts, 23, 21))
+}
+