Always cache union and intersection relations

src/compiler/checker.ts

@@ -18207,13 +18207,12 @@ namespace ts {
                 let result = Ternary.False;
                 const saveErrorInfo = captureErrorCalculationState();
 
-                // Note that these checks are specifically ordered to produce correct results. In particular,
-                // we need to deconstruct unions before intersections (because unions are always at the top),
-                // and we need to handle "each" relations before "some" relations for the same kind of type.
-                if (source.flags & TypeFlags.UnionOrIntersection || target.flags & TypeFlags.UnionOrIntersection) {
-                    result = getConstituentCount(source) * getConstituentCount(target) >= 4 ?
-                        recursiveTypeRelatedTo(source, target, reportErrors, intersectionState | IntersectionState.UnionIntersectionCheck, recursionFlags) :
-                        structuredTypeRelatedTo(source, target, reportErrors, intersectionState | IntersectionState.UnionIntersectionCheck);
+                if ((source.flags & TypeFlags.Union || target.flags & TypeFlags.Union) && getConstituentCount(source) * getConstituentCount(target) < 0) {
+                    // We skip caching when source or target is a union with no more than three constituents.
+                    result = structuredTypeRelatedTo(source, target, reportErrors, intersectionState | IntersectionState.UnionIntersectionCheck);
+                }
+                else if (source.flags & TypeFlags.UnionOrIntersection || target.flags & TypeFlags.UnionOrIntersection) {
+                    result = recursiveTypeRelatedTo(source, target, reportErrors, intersectionState | IntersectionState.UnionIntersectionCheck, recursionFlags);
                 }
                 if (!result && !(source.flags & TypeFlags.Union) && (source.flags & (TypeFlags.StructuredOrInstantiable) || target.flags & TypeFlags.StructuredOrInstantiable)) {
                     if (result = recursiveTypeRelatedTo(source, target, reportErrors, intersectionState, recursionFlags)) {
@@ -18677,17 +18676,17 @@ namespace ts {
                 const maybeStart = maybeCount;
                 maybeKeys[maybeCount] = id;
                 maybeCount++;
+                const saveExpandingFlags = expandingFlags;
                 if (recursionFlags & RecursionFlags.Source) {
                     sourceStack[sourceDepth] = source;
                     sourceDepth++;
+                    if (!(expandingFlags & ExpandingFlags.Source) && isDeeplyNestedType(source, sourceStack, sourceDepth)) expandingFlags |= ExpandingFlags.Source;
                 }
                 if (recursionFlags & RecursionFlags.Target) {
                     targetStack[targetDepth] = target;
                     targetDepth++;
+                    if (!(expandingFlags & ExpandingFlags.Target) && isDeeplyNestedType(target, targetStack, targetDepth)) expandingFlags |= ExpandingFlags.Target;
                 }
-                const saveExpandingFlags = expandingFlags;
-                if (!(expandingFlags & ExpandingFlags.Source) && isDeeplyNestedType(source, sourceStack, sourceDepth)) expandingFlags |= ExpandingFlags.Source;
-                if (!(expandingFlags & ExpandingFlags.Target) && isDeeplyNestedType(target, targetStack, targetDepth)) expandingFlags |= ExpandingFlags.Target;
                 let originalHandler: typeof outofbandVarianceMarkerHandler;
                 let propagatingVarianceFlags: RelationComparisonResult = 0;
                 if (outofbandVarianceMarkerHandler) {
@@ -18713,13 +18712,13 @@ namespace ts {
                 if (outofbandVarianceMarkerHandler) {
                     outofbandVarianceMarkerHandler = originalHandler;
                 }
-                expandingFlags = saveExpandingFlags;
                 if (recursionFlags & RecursionFlags.Source) {
                     sourceDepth--;
                 }
                 if (recursionFlags & RecursionFlags.Target) {
                     targetDepth--;
                 }
+                expandingFlags = saveExpandingFlags;
                 if (result) {
                     if (result === Ternary.True || (sourceDepth === 0 && targetDepth === 0)) {
                         if (result === Ternary.True || result === Ternary.Maybe) {
@@ -23150,7 +23149,7 @@ namespace ts {
         }
 
         function getConstituentCount(type: Type) {
-            return type.flags & TypeFlags.UnionOrIntersection ? (type as UnionOrIntersectionType).types.length : 1;
+            return type.flags & TypeFlags.Union ? (type as UnionType).types.length : 1;
         }
 
         function extractTypesOfKind(type: Type, kind: TypeFlags) {

tests/baselines/reference/complicatedIndexedAccessKeyofReliesOnKeyofNeverUpperBound.errors.txt

@@ -9,16 +9,14 @@ tests/cases/compiler/complicatedIndexedAccessKeyofReliesOnKeyofNeverUpperBound.t
                 Type '"text" | "email"' is not assignable to type 'ChannelOfType<T, TextChannel>["type"]'.
                   Type '"text"' is not assignable to type 'ChannelOfType<T, TextChannel>["type"]'.
                     Type '"text"' is not assignable to type 'T & "text"'.
-                      Type '"text"' is not assignable to type 'T'.
-                        '"text"' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '"text" | "email"'.
-                          Type 'T' is not assignable to type 'T & "text"'.
-                            Type '"text" | "email"' is not assignable to type 'T & "text"'.
-                              Type '"text"' is not assignable to type 'T & "text"'.
-                                Type '"text"' is not assignable to type 'T'.
-                                  '"text"' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '"text" | "email"'.
-                                    Type 'T' is not assignable to type '"text"'.
-                                      Type '"text" | "email"' is not assignable to type '"text"'.
-                                        Type '"email"' is not assignable to type '"text"'.
+                      Type 'T' is not assignable to type 'T & "text"'.
+                        Type '"text" | "email"' is not assignable to type 'T & "text"'.
+                          Type '"text"' is not assignable to type 'T & "text"'.
+                            Type '"text"' is not assignable to type 'T'.
+                              '"text"' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '"text" | "email"'.
+                                Type 'T' is not assignable to type '"text"'.
+                                  Type '"text" | "email"' is not assignable to type '"text"'.
+                                    Type '"email"' is not assignable to type '"text"'.
 
 
 ==== tests/cases/compiler/complicatedIndexedAccessKeyofReliesOnKeyofNeverUpperBound.ts (1 errors) ====
@@ -67,16 +65,14 @@ tests/cases/compiler/complicatedIndexedAccessKeyofReliesOnKeyofNeverUpperBound.t
 !!! error TS2322:                 Type '"text" | "email"' is not assignable to type 'ChannelOfType<T, TextChannel>["type"]'.
 !!! error TS2322:                   Type '"text"' is not assignable to type 'ChannelOfType<T, TextChannel>["type"]'.
 !!! error TS2322:                     Type '"text"' is not assignable to type 'T & "text"'.
-!!! error TS2322:                       Type '"text"' is not assignable to type 'T'.
-!!! error TS2322:                         '"text"' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '"text" | "email"'.
-!!! error TS2322:                           Type 'T' is not assignable to type 'T & "text"'.
-!!! error TS2322:                             Type '"text" | "email"' is not assignable to type 'T & "text"'.
-!!! error TS2322:                               Type '"text"' is not assignable to type 'T & "text"'.
-!!! error TS2322:                                 Type '"text"' is not assignable to type 'T'.
-!!! error TS2322:                                   '"text"' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '"text" | "email"'.
-!!! error TS2322:                                     Type 'T' is not assignable to type '"text"'.
-!!! error TS2322:                                       Type '"text" | "email"' is not assignable to type '"text"'.
-!!! error TS2322:                                         Type '"email"' is not assignable to type '"text"'.
+!!! error TS2322:                       Type 'T' is not assignable to type 'T & "text"'.
+!!! error TS2322:                         Type '"text" | "email"' is not assignable to type 'T & "text"'.
+!!! error TS2322:                           Type '"text"' is not assignable to type 'T & "text"'.
+!!! error TS2322:                             Type '"text"' is not assignable to type 'T'.
+!!! error TS2322:                               '"text"' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '"text" | "email"'.
+!!! error TS2322:                                 Type 'T' is not assignable to type '"text"'.
+!!! error TS2322:                                   Type '"text" | "email"' is not assignable to type '"text"'.
+!!! error TS2322:                                     Type '"email"' is not assignable to type '"text"'.
     }
     
     const newTextChannel = makeNewChannel('text');

tests/baselines/reference/deepComparisons.errors.txt

@@ -46,4 +46,23 @@ tests/cases/compiler/deepComparisons.ts(4,9): error TS2322: Type 'T[K1][K2]' is
     
     function f3<U>() {
         let x: Foo1<U> = 0 as any as Bar<U>;  // No error!
-    }
+    }
+    
+    // Repro from #46500
+    
+    type F<T> = {} & (
+        T extends [any, ...any[]]
+            ? { [K in keyof T]?: F<T[K]> }
+            : T extends any[]
+                ? F<T[number]>[]
+                : T extends { [K: string]: any }
+                    ? { [K in keyof T]?: F<T[K]> }
+                    : { x: string }
+    );
+    
+    declare function f<T = any>(): F<T>;
+    
+    function g() {
+        return f() as F<any>;
+    }
+    

tests/baselines/reference/deepComparisons.js

@@ -17,7 +17,26 @@ type Foo2<T> = { x: Foo1<T> };
 
 function f3<U>() {
     let x: Foo1<U> = 0 as any as Bar<U>;  // No error!
-}
+}
+
+// Repro from #46500
+
+type F<T> = {} & (
+    T extends [any, ...any[]]
+        ? { [K in keyof T]?: F<T[K]> }
+        : T extends any[]
+            ? F<T[number]>[]
+            : T extends { [K: string]: any }
+                ? { [K in keyof T]?: F<T[K]> }
+                : { x: string }
+);
+
+declare function f<T = any>(): F<T>;
+
+function g() {
+    return f() as F<any>;
+}
+
 
 //// [deepComparisons.js]
 function f1() {
@@ -31,3 +50,6 @@ function f2() {
 function f3() {
     var x = 0; // No error!
 }
+function g() {
+    return f();
+}

tests/baselines/reference/deepComparisons.symbols

@@ -84,3 +84,57 @@ function f3<U>() {
 >Bar : Symbol(Bar, Decl(deepComparisons.ts, 6, 28))
 >U : Symbol(U, Decl(deepComparisons.ts, 16, 12))
 }
+
+// Repro from #46500
+
+type F<T> = {} & (
+>F : Symbol(F, Decl(deepComparisons.ts, 18, 1))
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+
+    T extends [any, ...any[]]
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+
+        ? { [K in keyof T]?: F<T[K]> }
+>K : Symbol(K, Decl(deepComparisons.ts, 24, 13))
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+>F : Symbol(F, Decl(deepComparisons.ts, 18, 1))
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+>K : Symbol(K, Decl(deepComparisons.ts, 24, 13))
+
+        : T extends any[]
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+
+            ? F<T[number]>[]
+>F : Symbol(F, Decl(deepComparisons.ts, 18, 1))
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+
+            : T extends { [K: string]: any }
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+>K : Symbol(K, Decl(deepComparisons.ts, 27, 27))
+
+                ? { [K in keyof T]?: F<T[K]> }
+>K : Symbol(K, Decl(deepComparisons.ts, 28, 21))
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+>F : Symbol(F, Decl(deepComparisons.ts, 18, 1))
+>T : Symbol(T, Decl(deepComparisons.ts, 22, 7))
+>K : Symbol(K, Decl(deepComparisons.ts, 28, 21))
+
+                : { x: string }
+>x : Symbol(x, Decl(deepComparisons.ts, 29, 19))
+
+);
+
+declare function f<T = any>(): F<T>;
+>f : Symbol(f, Decl(deepComparisons.ts, 30, 2))
+>T : Symbol(T, Decl(deepComparisons.ts, 32, 19))
+>F : Symbol(F, Decl(deepComparisons.ts, 18, 1))
+>T : Symbol(T, Decl(deepComparisons.ts, 32, 19))
+
+function g() {
+>g : Symbol(g, Decl(deepComparisons.ts, 32, 36))
+
+    return f() as F<any>;
+>f : Symbol(f, Decl(deepComparisons.ts, 30, 2))
+>F : Symbol(F, Decl(deepComparisons.ts, 18, 1))
+}
+

tests/baselines/reference/deepComparisons.types

@@ -56,3 +56,34 @@ function f3<U>() {
 >0 as any : any
 >0 : 0
 }
+
+// Repro from #46500
+
+type F<T> = {} & (
+>F : F<T>
+
+    T extends [any, ...any[]]
+        ? { [K in keyof T]?: F<T[K]> }
+        : T extends any[]
+            ? F<T[number]>[]
+            : T extends { [K: string]: any }
+>K : string
+
+                ? { [K in keyof T]?: F<T[K]> }
+                : { x: string }
+>x : string
+
+);
+
+declare function f<T = any>(): F<T>;
+>f : <T = any>() => F<T>
+
+function g() {
+>g : () => F<any>
+
+    return f() as F<any>;
+>f() as F<any> : F<any>
+>f() : F<any>
+>f : <T = any>() => F<T>
+}
+

tests/baselines/reference/intersectionAndUnionTypes.errors.txt

@@ -5,7 +5,6 @@ tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(20,1): e
 tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(23,1): 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 & B'.
-      Type 'A' is not assignable to type 'B'.
 tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(25,1): 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 'C & D'.
@@ -80,7 +79,6 @@ tests/cases/conformance/types/intersection/intersectionAndUnionTypes.ts(37,1): e
 !!! 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 & B'.
-!!! error TS2322:       Type 'A' is not assignable to type 'B'.
     x = cnd;  // Ok
     x = cod;
     ~

tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt

@@ -33,8 +33,11 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(82,5): error
             Type 'string | number | symbol' is not assignable to type 'keyof U'.
               Type 'string' is not assignable to type 'keyof U'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(83,5): error TS2322: Type 'keyof T | keyof U' is not assignable to type 'keyof T & keyof U'.
+  Type 'keyof T' is not assignable to type 'keyof T & keyof U'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(86,5): error TS2322: Type 'keyof T | keyof U' is not assignable to type 'keyof T & keyof U'.
+  Type 'keyof T' is not assignable to type 'keyof T & keyof U'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(87,5): error TS2322: Type 'keyof T | keyof U' is not assignable to type 'keyof T & keyof U'.
+  Type 'keyof T' is not assignable to type 'keyof T & keyof U'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(103,9): error TS2322: Type 'Extract<keyof T, string>' is not assignable to type 'K'.
   'Extract<keyof T, string>' is assignable to the constraint of type 'K', but 'K' could be instantiated with a different subtype of constraint 'string'.
     Type 'string & keyof T' is not assignable to type 'K'.
@@ -209,14 +212,17 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(142,5): error
         k1 = k4;  // Error
         ~~
 !!! error TS2322: Type 'keyof T | keyof U' is not assignable to type 'keyof T & keyof U'.
+!!! error TS2322:   Type 'keyof T' is not assignable to type 'keyof T & keyof U'.
     
         k2 = k1;
         k2 = k3;  // Error
         ~~
 !!! error TS2322: Type 'keyof T | keyof U' is not assignable to type 'keyof T & keyof U'.
+!!! error TS2322:   Type 'keyof T' is not assignable to type 'keyof T & keyof U'.
         k2 = k4;  // Error
         ~~
 !!! error TS2322: Type 'keyof T | keyof U' is not assignable to type 'keyof T & keyof U'.
+!!! error TS2322:   Type 'keyof T' is not assignable to type 'keyof T & keyof U'.
     
         k3 = k1;
         k3 = k2;

tests/baselines/reference/unionTypeCallSignatures6.errors.txt

@@ -6,14 +6,12 @@ tests/cases/conformance/types/union/unionTypeCallSignatures6.ts(38,4): error TS2
 tests/cases/conformance/types/union/unionTypeCallSignatures6.ts(39,1): error TS2684: The 'this' context of type 'A & C & { f0: F0 | F3; f1: F1 | F3; f2: F1 | F4; f3: F3 | F4; f4: F3 | F5; }' is not assignable to method's 'this' of type 'B'.
   Property 'b' is missing in type 'A & C & { f0: F0 | F3; f1: F1 | F3; f2: F1 | F4; f3: F3 | F4; f4: F3 | F5; }' but required in type 'B'.
 tests/cases/conformance/types/union/unionTypeCallSignatures6.ts(48,1): error TS2684: The 'this' context of type 'void' is not assignable to method's 'this' of type 'A & B'.
-  Type 'void' is not assignable to type 'A'.
 tests/cases/conformance/types/union/unionTypeCallSignatures6.ts(55,1): error TS2769: No overload matches this call.
   Overload 1 of 2, '(this: A & B & C): void', gave the following error.
     The 'this' context of type 'void' is not assignable to method's 'this' of type 'A & B & C'.
       Type 'void' is not assignable to type 'A'.
   Overload 2 of 2, '(this: A & B): void', gave the following error.
     The 'this' context of type 'void' is not assignable to method's 'this' of type 'A & B'.
-      Type 'void' is not assignable to type 'A'.
 
 
 ==== tests/cases/conformance/types/union/unionTypeCallSignatures6.ts (6 errors) ====
@@ -79,7 +77,6 @@ tests/cases/conformance/types/union/unionTypeCallSignatures6.ts(55,1): error TS2
     f3(); // error
     ~~~~
 !!! error TS2684: The 'this' context of type 'void' is not assignable to method's 'this' of type 'A & B'.
-!!! error TS2684:   Type 'void' is not assignable to type 'A'.
     
     interface F7 {
       (this: A & B & C): void;
@@ -94,5 +91,4 @@ tests/cases/conformance/types/union/unionTypeCallSignatures6.ts(55,1): error TS2
 !!! error TS2769:       Type 'void' is not assignable to type 'A'.
 !!! error TS2769:   Overload 2 of 2, '(this: A & B): void', gave the following error.
 !!! error TS2769:     The 'this' context of type 'void' is not assignable to method's 'this' of type 'A & B'.
-!!! error TS2769:       Type 'void' is not assignable to type 'A'.
     

tests/cases/compiler/deepComparisons.ts

@@ -16,4 +16,22 @@ type Foo2<T> = { x: Foo1<T> };
 
 function f3<U>() {
     let x: Foo1<U> = 0 as any as Bar<U>;  // No error!
-}
+}
+
+// Repro from #46500
+
+type F<T> = {} & (
+    T extends [any, ...any[]]
+        ? { [K in keyof T]?: F<T[K]> }
+        : T extends any[]
+            ? F<T[number]>[]
+            : T extends { [K: string]: any }
+                ? { [K in keyof T]?: F<T[K]> }
+                : { x: string }
+);
+
+declare function f<T = any>(): F<T>;
+
+function g() {
+    return f() as F<any>;
+}