Limit to single overlappy type to improve back other errors

src/compiler/checker.ts

@@ -21985,7 +21985,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             }
             if (reportErrors) {
                 // Elaborate only if we can find a best matching type in the target
-                const bestMatchingType = getBestMatchingType(source, target, isRelatedTo);
+                const bestMatchingType = getBestMatchingType(source, target, isRelatedTo, /*singleOverlappy*/ true);
                 if (bestMatchingType) {
                     isRelatedTo(source, bestMatchingType, RecursionFlags.Target, /*reportErrors*/ true, /*headMessage*/ undefined, intersectionState);
                 }
@@ -23712,11 +23712,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         return getPropertiesOfType(type).filter(targetProp => containsMissingType(getTypeOfSymbol(targetProp)));
     }
 
-    function getBestMatchingType(source: Type, target: UnionOrIntersectionType, isRelatedTo = compareTypesAssignable) {
+    function getBestMatchingType(source: Type, target: UnionOrIntersectionType, isRelatedTo = compareTypesAssignable, singleOverlappy = false) {
         return findMatchingDiscriminantType(source, target, isRelatedTo) ||
             findMatchingTypeReferenceOrTypeAliasReference(source, target) ||
             findBestTypeForInvokable(source, target) ||
-            findMostOverlappyType(source, filterTypesForObjectLiteralMatch(source, target));
+            findMostOverlappyType(source, filterTypesForObjectLiteralMatch(source, target), singleOverlappy);
     }
 
     function discriminateTypeByDiscriminableItems(target: UnionType, discriminators: (readonly [() => Type, __String])[], related: (source: Type, target: Type) => boolean | Ternary) {
@@ -50924,7 +50924,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
     }
 
-    function findMostOverlappyType(source: Type, target: Type) {
+    function findMostOverlappyType(source: Type, target: Type, singleOverlappy: boolean) {
         if (!(target.flags & TypeFlags.UnionOrIntersection)) {
             return target;
         }
@@ -50954,7 +50954,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 }
             }
         }
-        return bestMatches.length ? getUnionType(bestMatches) : undefined;
+        return bestMatches.length ? singleOverlappy ? bestMatches[0] : getUnionType(bestMatches) : undefined;
     }
 
     function filterPrimitivesIfContainsNonPrimitive(type: UnionType) {

tests/baselines/reference/assignmentCompatWithDiscriminatedUnion.errors.txt

@@ -1,7 +1,15 @@
 assignmentCompatWithDiscriminatedUnion.ts(44,5): error TS2322: Type 'S' is not assignable to type 'T'.
   Type 'S' is not assignable to type '{ a: 0; b: 4 | 1; } | { a: 1; b: 2 | 4; }'.
+    Type 'S' is not assignable to type '{ a: 0; b: 4 | 1; }'.
+      Types of property 'a' are incompatible.
+        Type '0 | 2' is not assignable to type '0'.
+          Type '2' is not assignable to type '0'.
 assignmentCompatWithDiscriminatedUnion.ts(58,5): error TS2322: Type 'S' is not assignable to type 'T'.
   Type 'S' is not assignable to type '{ a: 0; b: 4 | 1; } | { a: 2; b: 4 | 3; c: string; }'.
+    Type 'S' is not assignable to type '{ a: 0; b: 4 | 1; }'.
+      Types of property 'a' are incompatible.
+        Type '0 | 2' is not assignable to type '0'.
+          Type '2' is not assignable to type '0'.
 assignmentCompatWithDiscriminatedUnion.ts(82,5): error TS2322: Type 'S' is not assignable to type 'T'.
 
 
@@ -53,6 +61,10 @@ assignmentCompatWithDiscriminatedUnion.ts(82,5): error TS2322: Type 'S' is not a
         ~
 !!! error TS2322: Type 'S' is not assignable to type 'T'.
 !!! error TS2322:   Type 'S' is not assignable to type '{ a: 0; b: 4 | 1; } | { a: 1; b: 2 | 4; }'.
+!!! error TS2322:     Type 'S' is not assignable to type '{ a: 0; b: 4 | 1; }'.
+!!! error TS2322:       Types of property 'a' are incompatible.
+!!! error TS2322:         Type '0 | 2' is not assignable to type '0'.
+!!! error TS2322:           Type '2' is not assignable to type '0'.
     }
 
     // Unmatched non-discriminants
@@ -70,6 +82,10 @@ assignmentCompatWithDiscriminatedUnion.ts(82,5): error TS2322: Type 'S' is not a
         ~
 !!! error TS2322: Type 'S' is not assignable to type 'T'.
 !!! error TS2322:   Type 'S' is not assignable to type '{ a: 0; b: 4 | 1; } | { a: 2; b: 4 | 3; c: string; }'.
+!!! error TS2322:     Type 'S' is not assignable to type '{ a: 0; b: 4 | 1; }'.
+!!! error TS2322:       Types of property 'a' are incompatible.
+!!! error TS2322:         Type '0 | 2' is not assignable to type '0'.
+!!! error TS2322:           Type '2' is not assignable to type '0'.
     }
 
     // Maximum discriminant combinations

tests/baselines/reference/bigintWithLib.errors.txt

@@ -11,7 +11,7 @@ bigintWithLib.ts(19,33): error TS2769: No overload matches this call.
               Type 'number' is not assignable to type 'bigint'.
   Overload 3 of 3, '(buffer: ArrayBufferLike, byteOffset?: number, length?: number): BigInt64Array', gave the following error.
     Argument of type 'number[]' is not assignable to parameter of type 'ArrayBufferLike'.
-      Type 'number[]' is not assignable to type 'ArrayBuffer | SharedArrayBuffer'.
+      Type 'number[]' is missing the following properties from type 'ArrayBuffer': byteLength, [Symbol.toStringTag]
 bigintWithLib.ts(24,13): error TS2540: Cannot assign to 'length' because it is a read-only property.
 bigintWithLib.ts(31,35): error TS2769: No overload matches this call.
   Overload 1 of 3, '(length?: number): BigUint64Array', gave the following error.
@@ -60,7 +60,7 @@ bigintWithLib.ts(46,26): error TS2345: Argument of type 'number' is not assignab
 !!! error TS2769:               Type 'number' is not assignable to type 'bigint'.
 !!! error TS2769:   Overload 3 of 3, '(buffer: ArrayBufferLike, byteOffset?: number, length?: number): BigInt64Array', gave the following error.
 !!! error TS2769:     Argument of type 'number[]' is not assignable to parameter of type 'ArrayBufferLike'.
-!!! error TS2769:       Type 'number[]' is not assignable to type 'ArrayBuffer | SharedArrayBuffer'.
+!!! error TS2769:       Type 'number[]' is missing the following properties from type 'ArrayBuffer': byteLength, [Symbol.toStringTag]
     bigIntArray = new BigInt64Array(new ArrayBuffer(80));
     bigIntArray = new BigInt64Array(new ArrayBuffer(80), 8);
     bigIntArray = new BigInt64Array(new ArrayBuffer(80), 8, 3);

tests/baselines/reference/contextualTypeWithUnionTypeObjectLiteral.errors.txt

@@ -1,13 +1,19 @@
 contextualTypeWithUnionTypeObjectLiteral.ts(14,5): error TS2322: Type '{ prop: string | number; }' is not assignable to type '{ prop: string; } | { prop: number; }'.
-  Type '{ prop: string | number; }' is not assignable to type '{ prop: string; } | { prop: number; }'.
+  Type '{ prop: string | number; }' is not assignable to type '{ prop: string; }'.
+    Types of property 'prop' are incompatible.
+      Type 'string | number' is not assignable to type 'string'.
+        Type 'number' is not assignable to type 'string'.
 contextualTypeWithUnionTypeObjectLiteral.ts(20,5): error TS2322: Type '{ prop: string | number; }' is not assignable to type '{ prop: string; anotherP: string; } | { prop: number; }'.
-  Type '{ prop: string | number; }' is not assignable to type '{ prop: string; anotherP: string; } | { prop: number; }'.
+  Property 'anotherP' is missing in type '{ prop: string | number; }' but required in type '{ prop: string; anotherP: string; }'.
 contextualTypeWithUnionTypeObjectLiteral.ts(22,5): error TS2322: Type 'string | number' is not assignable to type 'string'.
   Type 'number' is not assignable to type 'string'.
 contextualTypeWithUnionTypeObjectLiteral.ts(26,5): error TS2322: Type 'string | number' is not assignable to type 'string'.
   Type 'number' is not assignable to type 'string'.
 contextualTypeWithUnionTypeObjectLiteral.ts(29,5): error TS2322: Type '{ prop: string | number; anotherP: string; anotherP1: number; }' is not assignable to type '{ prop: string; anotherP: string; } | { prop: number; anotherP1: number; }'.
-  Type '{ prop: string | number; anotherP: string; anotherP1: number; }' is not assignable to type '{ prop: string; anotherP: string; } | { prop: number; anotherP1: number; }'.
+  Type '{ prop: string | number; anotherP: string; anotherP1: number; }' is not assignable to type '{ prop: string; anotherP: string; }'.
+    Types of property 'prop' are incompatible.
+      Type 'string | number' is not assignable to type 'string'.
+        Type 'number' is not assignable to type 'string'.
 contextualTypeWithUnionTypeObjectLiteral.ts(58,5): error TS2322: Type '(a: string, b: number) => string | number' is not assignable to type '((a: string, b: number) => string) | ((a: string, b: number) => number)'.
   Type '(a: string, b: number) => string | number' is not assignable to type '(a: string, b: number) => string'.
     Type 'string | number' is not assignable to type 'string'.
@@ -31,7 +37,10 @@ contextualTypeWithUnionTypeObjectLiteral.ts(58,5): error TS2322: Type '(a: strin
     var objStrOrNum3: { prop: string } | { prop: number } = {
         ~~~~~~~~~~~~
 !!! error TS2322: Type '{ prop: string | number; }' is not assignable to type '{ prop: string; } | { prop: number; }'.
-!!! error TS2322:   Type '{ prop: string | number; }' is not assignable to type '{ prop: string; } | { prop: number; }'.
+!!! error TS2322:   Type '{ prop: string | number; }' is not assignable to type '{ prop: string; }'.
+!!! error TS2322:     Types of property 'prop' are incompatible.
+!!! error TS2322:       Type 'string | number' is not assignable to type 'string'.
+!!! error TS2322:         Type 'number' is not assignable to type 'string'.
         prop: strOrNumber
     };
     var objStrOrNum4: { prop: string | number } = {
@@ -40,7 +49,8 @@ contextualTypeWithUnionTypeObjectLiteral.ts(58,5): error TS2322: Type '(a: strin
     var objStrOrNum5: { prop: string; anotherP: string; } | { prop: number } = { prop: strOrNumber };
         ~~~~~~~~~~~~
 !!! error TS2322: Type '{ prop: string | number; }' is not assignable to type '{ prop: string; anotherP: string; } | { prop: number; }'.
-!!! error TS2322:   Type '{ prop: string | number; }' is not assignable to type '{ prop: string; anotherP: string; } | { prop: number; }'.
+!!! error TS2322:   Property 'anotherP' is missing in type '{ prop: string | number; }' but required in type '{ prop: string; anotherP: string; }'.
+!!! related TS2728 contextualTypeWithUnionTypeObjectLiteral.ts:20:35: 'anotherP' is declared here.
     var objStrOrNum6: { prop: string; anotherP: string; } | { prop: number } = {
         prop: strOrNumber,
         ~~~~
@@ -60,7 +70,10 @@ contextualTypeWithUnionTypeObjectLiteral.ts(58,5): error TS2322: Type '(a: strin
     var objStrOrNum8: { prop: string; anotherP: string; } | { prop: number; anotherP1: number } = {
         ~~~~~~~~~~~~
 !!! error TS2322: Type '{ prop: string | number; anotherP: string; anotherP1: number; }' is not assignable to type '{ prop: string; anotherP: string; } | { prop: number; anotherP1: number; }'.
-!!! error TS2322:   Type '{ prop: string | number; anotherP: string; anotherP1: number; }' is not assignable to type '{ prop: string; anotherP: string; } | { prop: number; anotherP1: number; }'.
+!!! error TS2322:   Type '{ prop: string | number; anotherP: string; anotherP1: number; }' is not assignable to type '{ prop: string; anotherP: string; }'.
+!!! error TS2322:     Types of property 'prop' are incompatible.
+!!! error TS2322:       Type 'string | number' is not assignable to type 'string'.
+!!! error TS2322:         Type 'number' is not assignable to type 'string'.
         prop: strOrNumber,
         anotherP: str,
         anotherP1: num

tests/baselines/reference/excessPropertyCheckWithUnions.errors.txt

@@ -6,6 +6,7 @@ excessPropertyCheckWithUnions.ts(33,28): error TS2353: Object literal may only s
 excessPropertyCheckWithUnions.ts(34,26): error TS2353: Object literal may only specify known properties, and 'extra' does not exist in type '{ tag: "A"; x: string; } | { tag: "A"; y: number; }'.
 excessPropertyCheckWithUnions.ts(37,1): error TS2322: Type '{ tag: "A"; }' is not assignable to type 'Ambiguous'.
   Type '{ tag: "A"; }' is not assignable to type '{ tag: "A"; x: string; } | { tag: "A"; y: number; }'.
+    Property 'x' is missing in type '{ tag: "A"; }' but required in type '{ tag: "A"; x: string; }'.
 excessPropertyCheckWithUnions.ts(38,19): error TS2353: Object literal may only specify known properties, and 'z' does not exist in type '{ tag: "A"; x: string; } | { tag: "A"; y: number; }'.
 excessPropertyCheckWithUnions.ts(47,35): error TS2353: Object literal may only specify known properties, and 'second' does not exist in type '{ a: 1; b: 1; first: string; }'.
 excessPropertyCheckWithUnions.ts(48,35): error TS2353: Object literal may only specify known properties, and 'third' does not exist in type '{ a: 1; b: 1; first: string; }'.
@@ -69,6 +70,8 @@ excessPropertyCheckWithUnions.ts(112,63): error TS2322: Type 'string' is not ass
     ~~~
 !!! error TS2322: Type '{ tag: "A"; }' is not assignable to type 'Ambiguous'.
 !!! error TS2322:   Type '{ tag: "A"; }' is not assignable to type '{ tag: "A"; x: string; } | { tag: "A"; y: number; }'.
+!!! error TS2322:     Property 'x' is missing in type '{ tag: "A"; }' but required in type '{ tag: "A"; x: string; }'.
+!!! related TS2728 excessPropertyCheckWithUnions.ts:16:5: 'x' is declared here.
     amb = { tag: "A", z: true }
                       ~
 !!! error TS2353: Object literal may only specify known properties, and 'z' does not exist in type '{ tag: "A"; x: string; } | { tag: "A"; y: number; }'.

tests/baselines/reference/genericRestParameters3.errors.txt

@@ -2,6 +2,8 @@ genericRestParameters3.ts(17,11): error TS2345: Argument of type '[10]' is not a
   Type '[10]' is not assignable to type '[string]'.
     Type 'number' is not assignable to type 'string'.
 genericRestParameters3.ts(18,1): error TS2345: Argument of type '[]' is not assignable to parameter of type '[string] | [number, boolean]'.
+  Type '[]' is not assignable to type '[string]'.
+    Source has 0 element(s) but target requires 1.
 genericRestParameters3.ts(23,1): error TS2322: Type '(x: string, y: string) => void' is not assignable to type '(x: string, ...args: [string] | [number, boolean]) => void'.
   Types of parameters 'y' and 'args' are incompatible.
     Type '[string] | [number, boolean]' is not assignable to type '[y: string]'.
@@ -57,6 +59,8 @@ genericRestParameters3.ts(59,5): error TS2345: Argument of type '["what"]' is no
     f1("foo");  // Error
     ~~~~~~~~~
 !!! error TS2345: Argument of type '[]' is not assignable to parameter of type '[string] | [number, boolean]'.
+!!! error TS2345:   Type '[]' is not assignable to type '[string]'.
+!!! error TS2345:     Source has 0 element(s) but target requires 1.
 
     f2 = f1;
     f3 = f1;

tests/baselines/reference/intersectionAndUnionTypes.errors.txt

@@ -20,15 +20,19 @@ intersectionAndUnionTypes.ts(28,1): error TS2322: Type '(A & B) | (C & D)' is no
 intersectionAndUnionTypes.ts(29,1): error TS2322: Type '(A & B) | (C & D)' is not assignable to type 'C | D'.
   Type 'A & B' is not assignable to type 'C | D'.
 intersectionAndUnionTypes.ts(31,1): error TS2322: Type 'A & B' is not assignable to type '(A | B) & (C | D)'.
-  Type 'A & B' is not assignable to type '(A & C) | (A & D) | (B & C) | (B & D)'.
+  Type 'A & B' is not assignable to type 'A & C'.
+    Type 'A & B' is not assignable to type 'C'.
 intersectionAndUnionTypes.ts(32,1): error TS2322: Type 'A | B' is not assignable to type '(A | B) & (C | D)'.
   Type 'A' is not assignable to type '(A | B) & (C | D)'.
-    Type 'A' is not assignable to type '(A & C) | (A & D)'.
+    Type 'A' is not assignable to type 'A & C'.
+      Property 'c' is missing in type 'A' but required in type 'C'.
 intersectionAndUnionTypes.ts(33,1): error TS2322: Type 'C & D' is not assignable to type '(A | B) & (C | D)'.
-  Type 'C & D' is not assignable to type '(A & C) | (A & D) | (B & C) | (B & D)'.
+  Type 'C & D' is not assignable to type 'A & C'.
+    Type 'C & D' is not assignable to type 'A'.
 intersectionAndUnionTypes.ts(34,1): error TS2322: Type 'C | D' is not assignable to type '(A | B) & (C | D)'.
   Type 'C' is not assignable to type '(A | B) & (C | D)'.
-    Type 'C' is not assignable to type '(A & C) | (B & C)'.
+    Type 'C' is not assignable to type 'A & C'.
+      Property 'a' is missing in type 'C' but required in type 'A'.
 intersectionAndUnionTypes.ts(35,1): error TS2322: Type '(A | B) & (C | D)' is not assignable to type 'A & B'.
   Type 'A & C' is not assignable to type 'A & B'.
     Property 'b' is missing in type 'A & C' but required in type 'B'.
@@ -105,21 +109,27 @@ intersectionAndUnionTypes.ts(37,1): error TS2322: Type '(A | B) & (C | D)' is no
     y = anb;
     ~
 !!! error TS2322: Type 'A & B' is not assignable to type '(A | B) & (C | D)'.
-!!! error TS2322:   Type 'A & B' is not assignable to type '(A & C) | (A & D) | (B & C) | (B & D)'.
+!!! error TS2322:   Type 'A & B' is not assignable to type 'A & C'.
+!!! error TS2322:     Type 'A & B' is not assignable to type 'C'.
     y = aob;
     ~
 !!! error TS2322: Type 'A | B' is not assignable to type '(A | B) & (C | D)'.
 !!! error TS2322:   Type 'A' is not assignable to type '(A | B) & (C | D)'.
-!!! error TS2322:     Type 'A' is not assignable to type '(A & C) | (A & D)'.
+!!! error TS2322:     Type 'A' is not assignable to type 'A & C'.
+!!! error TS2322:       Property 'c' is missing in type 'A' but required in type 'C'.
+!!! related TS2728 intersectionAndUnionTypes.ts:3:15: 'c' is declared here.
     y = cnd;
     ~
 !!! error TS2322: Type 'C & D' is not assignable to type '(A | B) & (C | D)'.
-!!! error TS2322:   Type 'C & D' is not assignable to type '(A & C) | (A & D) | (B & C) | (B & D)'.
+!!! error TS2322:   Type 'C & D' is not assignable to type 'A & C'.
+!!! error TS2322:     Type 'C & D' is not assignable to type 'A'.
     y = cod;
     ~
 !!! error TS2322: Type 'C | D' is not assignable to type '(A | B) & (C | D)'.
 !!! error TS2322:   Type 'C' is not assignable to type '(A | B) & (C | D)'.
-!!! error TS2322:     Type 'C' is not assignable to type '(A & C) | (B & C)'.
+!!! error TS2322:     Type 'C' is not assignable to type 'A & C'.
+!!! error TS2322:       Property 'a' is missing in type 'C' but required in type 'A'.
+!!! related TS2728 intersectionAndUnionTypes.ts:1:15: 'a' is declared here.
     anb = y;
     ~~~
 !!! error TS2322: Type '(A | B) & (C | D)' is not assignable to type 'A & B'.

tests/baselines/reference/jsxComponentTypeErrors.errors.txt

@@ -18,6 +18,9 @@ jsxComponentTypeErrors.tsx(28,16): error TS2786: 'MixedComponent' cannot be used
   Its element type 'ClassComponent | { type: string | undefined; }' is not a valid JSX element.
     Type 'ClassComponent' is not assignable to type 'Element | ElementClass | null'.
       Type 'ClassComponent' is not assignable to type 'Element | ElementClass'.
+        Type 'ClassComponent' is not assignable to type 'Element'.
+          Types of property 'type' are incompatible.
+            Type 'string' is not assignable to type '"element"'.
 jsxComponentTypeErrors.tsx(37,16): error TS2786: 'obj.MemberFunctionComponent' cannot be used as a JSX component.
   Its return type '{}' is not a valid JSX element.
     Property 'type' is missing in type '{}' but required in type 'Element'.
@@ -80,6 +83,9 @@ jsxComponentTypeErrors.tsx(38,16): error TS2786: 'obj. MemberClassComponent' can
 !!! error TS2786:   Its element type 'ClassComponent | { type: string | undefined; }' is not a valid JSX element.
 !!! error TS2786:     Type 'ClassComponent' is not assignable to type 'Element | ElementClass | null'.
 !!! error TS2786:       Type 'ClassComponent' is not assignable to type 'Element | ElementClass'.
+!!! error TS2786:         Type 'ClassComponent' is not assignable to type 'Element'.
+!!! error TS2786:           Types of property 'type' are incompatible.
+!!! error TS2786:             Type 'string' is not assignable to type '"element"'.
 
     const obj = {
       MemberFunctionComponent() {