Consider all union types matching discriminator for excess property checks

src/compiler/checker.ts

@@ -22586,15 +22586,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         if (match === -1) {
             return defaultValue;
         }
-        // make sure exactly 1 matches before returning it
-        let nextMatch = discriminable.indexOf(/*searchElement*/ true, match + 1);
-        while (nextMatch !== -1) {
-            if (!isTypeIdenticalTo(target.types[match], target.types[nextMatch])) {
-                return defaultValue;
-            }
-            nextMatch = discriminable.indexOf(/*searchElement*/ true, nextMatch + 1);
-        }
-        return target.types[match];
+        return getUnionType(target.types.filter((_, index) => discriminable[index]));
     }
 
     /**

tests/baselines/reference/excessPropertyCheckWithMultipleDiscriminants.errors.txt

@@ -2,11 +2,19 @@ tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(30,5): erro
   Object literal may only specify known properties, and 'multipleOf' does not exist in type 'Float'.
 tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(41,5): error TS2322: Type '{ p1: "left"; p2: false; p3: number; p4: string; }' is not assignable to type 'DisjointDiscriminants'.
   Object literal may only specify known properties, and 'p3' does not exist in type '{ p1: "left"; p2: boolean; }'.
+tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(50,5): error TS2322: Type '{ p1: "left"; p2: true; p3: number; p4: string; }' is not assignable to type 'DisjointDiscriminants'.
+  Object literal may only specify known properties, and 'p4' does not exist in type '{ p1: "left"; p2: true; p3: number; } | { p1: "left"; p2: boolean; }'.
 tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(57,5): error TS2322: Type '{ p1: "right"; p2: false; p3: number; p4: string; }' is not assignable to type 'DisjointDiscriminants'.
   Object literal may only specify known properties, and 'p3' does not exist in type '{ p1: "right"; p2: false; p4: string; }'.
+tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(83,5): error TS2322: Type '{ type: "A"; n: number; a: number; b: number; }' is not assignable to type 'CommonWithOverlappingOptionals'.
+  Object literal may only specify known properties, and 'b' does not exist in type 'Common | (Common & A)'.
+tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(93,5): error TS2322: Type '{ type: "A"; n: number; a: number; b: number; }' is not assignable to type 'CommonWithDisjointOverlappingOptionals'.
+  Object literal may only specify known properties, and 'b' does not exist in type 'Common | A'.
+tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(130,5): error TS2322: Type '"string"' is not assignable to type '"number"'.
+tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(136,5): error TS2322: Type '"string"' is not assignable to type '"number"'.
 
 
-==== tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts (3 errors) ====
+==== tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts (8 errors) ====
     // Repro from #32657
 
     interface Base<T> {
@@ -57,12 +65,15 @@ tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(57,5): erro
         p4: "hello"
     };
 
-    // This has no excess error because variant one and three are both applicable.
+    // This has excess error because variant two is not applicable.
     const b: DisjointDiscriminants = {
         p1: 'left',
         p2: true,
         p3: 42,
         p4: "hello"
+        ~~
+!!! error TS2322: Type '{ p1: "left"; p2: true; p3: number; p4: string; }' is not assignable to type 'DisjointDiscriminants'.
+!!! error TS2322:   Object literal may only specify known properties, and 'p4' does not exist in type '{ p1: "left"; p2: true; p3: number; } | { p1: "left"; p2: boolean; }'.
     };
 
     // This has excess error because variant two is the only applicable case
@@ -75,4 +86,94 @@ tests/cases/compiler/excessPropertyCheckWithMultipleDiscriminants.ts(57,5): erro
 !!! error TS2322:   Object literal may only specify known properties, and 'p3' does not exist in type '{ p1: "right"; p2: false; p4: string; }'.
         p4: "hello"
     };
+
+    // Repro from #51873
+
+    interface Common {
+        type: "A" | "B" | "C" | "D";
+        n: number;
+    }
+    interface A {
+        type: "A";
+        a?: number;
+    }
+    interface B {
+        type: "B";
+        b?: number;
+    }
+
+    type CommonWithOverlappingOptionals = Common | (Common & A) | (Common & B);
+
+    // Should reject { b } because reduced to Common | (Common & A)
+    const c1: CommonWithOverlappingOptionals = {
+        type: "A",
+        n: 1,
+        a: 1,
+        b: 1  // excess property
+        ~
+!!! error TS2322: Type '{ type: "A"; n: number; a: number; b: number; }' is not assignable to type 'CommonWithOverlappingOptionals'.
+!!! error TS2322:   Object literal may only specify known properties, and 'b' does not exist in type 'Common | (Common & A)'.
+    }
+
+    type CommonWithDisjointOverlappingOptionals = Common | A | B;
+
+    // Should still reject { b } because reduced to Common | A, even though these are now disjoint
+    const c2: CommonWithDisjointOverlappingOptionals = {
+        type: "A",
+        n: 1,
+        a: 1,
+        b: 1  // excess property
+        ~
+!!! error TS2322: Type '{ type: "A"; n: number; a: number; b: number; }' is not assignable to type 'CommonWithDisjointOverlappingOptionals'.
+!!! error TS2322:   Object literal may only specify known properties, and 'b' does not exist in type 'Common | A'.
+    }
+
+    // Repro from https://github.com/microsoft/TypeScript/pull/51884#issuecomment-1472736068
+
+    export type BaseAttribute<T> = {
+        type?: string | undefined;
+        required?: boolean | undefined;
+        defaultsTo?: T | undefined;
+    };
+
+    export type Attribute =
+        | string
+        | StringAttribute
+        | NumberAttribute
+        | OneToOneAttribute
+
+    export type Attribute2 =
+        | string
+        | StringAttribute
+        | NumberAttribute
+
+    export type StringAttribute = BaseAttribute<string> & {
+        type: 'string';
+    };
+
+    export type NumberAttribute = BaseAttribute<number> & {
+        type: 'number';
+        autoIncrement?: boolean | undefined;
+    };
+
+    export type OneToOneAttribute = BaseAttribute<any> & {
+        model: string;
+    };
+
+    // both should error due to excess properties
+    const attributes: Attribute = {
+        type: 'string',
+        ~~~~
+!!! error TS2322: Type '"string"' is not assignable to type '"number"'.
+        autoIncrement: true,
+        required: true,
+    };
+
+    const attributes2: Attribute2 = {
+        type: 'string',
+        ~~~~
+!!! error TS2322: Type '"string"' is not assignable to type '"number"'.
+        autoIncrement: true,
+        required: true,
+    };
 

tests/baselines/reference/excessPropertyCheckWithMultipleDiscriminants.js

@@ -43,7 +43,7 @@ const a: DisjointDiscriminants = {
     p4: "hello"
 };
 
-// This has no excess error because variant one and three are both applicable.
+// This has excess error because variant two is not applicable.
 const b: DisjointDiscriminants = {
     p1: 'left',
     p2: true,
@@ -58,10 +58,92 @@ const c: DisjointDiscriminants = {
     p3: 42,
     p4: "hello"
 };
+
+// Repro from #51873
+
+interface Common {
+    type: "A" | "B" | "C" | "D";
+    n: number;
+}
+interface A {
+    type: "A";
+    a?: number;
+}
+interface B {
+    type: "B";
+    b?: number;
+}
+
+type CommonWithOverlappingOptionals = Common | (Common & A) | (Common & B);
+
+// Should reject { b } because reduced to Common | (Common & A)
+const c1: CommonWithOverlappingOptionals = {
+    type: "A",
+    n: 1,
+    a: 1,
+    b: 1  // excess property
+}
+
+type CommonWithDisjointOverlappingOptionals = Common | A | B;
+
+// Should still reject { b } because reduced to Common | A, even though these are now disjoint
+const c2: CommonWithDisjointOverlappingOptionals = {
+    type: "A",
+    n: 1,
+    a: 1,
+    b: 1  // excess property
+}
+
+// Repro from https://github.com/microsoft/TypeScript/pull/51884#issuecomment-1472736068
+
+export type BaseAttribute<T> = {
+    type?: string | undefined;
+    required?: boolean | undefined;
+    defaultsTo?: T | undefined;
+};
+
+export type Attribute =
+    | string
+    | StringAttribute
+    | NumberAttribute
+    | OneToOneAttribute
+
+export type Attribute2 =
+    | string
+    | StringAttribute
+    | NumberAttribute
+
+export type StringAttribute = BaseAttribute<string> & {
+    type: 'string';
+};
+
+export type NumberAttribute = BaseAttribute<number> & {
+    type: 'number';
+    autoIncrement?: boolean | undefined;
+};
+
+export type OneToOneAttribute = BaseAttribute<any> & {
+    model: string;
+};
+
+// both should error due to excess properties
+const attributes: Attribute = {
+    type: 'string',
+    autoIncrement: true,
+    required: true,
+};
+
+const attributes2: Attribute2 = {
+    type: 'string',
+    autoIncrement: true,
+    required: true,
+};
 
 
 //// [excessPropertyCheckWithMultipleDiscriminants.js]
+"use strict";
 // Repro from #32657
+Object.defineProperty(exports, "__esModule", { value: true });
 var foo = {
     type: "number",
     value: 10,
@@ -75,7 +157,7 @@ var a = {
     p3: 42,
     p4: "hello"
 };
-// This has no excess error because variant one and three are both applicable.
+// This has excess error because variant two is not applicable.
 var b = {
     p1: 'left',
     p2: true,
@@ -89,3 +171,28 @@ var c = {
     p3: 42,
     p4: "hello"
 };
+// Should reject { b } because reduced to Common | (Common & A)
+var c1 = {
+    type: "A",
+    n: 1,
+    a: 1,
+    b: 1 // excess property
+};
+// Should still reject { b } because reduced to Common | A, even though these are now disjoint
+var c2 = {
+    type: "A",
+    n: 1,
+    a: 1,
+    b: 1 // excess property
+};
+// both should error due to excess properties
+var attributes = {
+    type: 'string',
+    autoIncrement: true,
+    required: true,
+};
+var attributes2 = {
+    type: 'string',
+    autoIncrement: true,
+    required: true,
+};