Fix mapped type instantiation circularity (microsoft#46586)

* Don't obtain constraint if doing so would cause circularity

* Add regression test

* Address CR feedback

Author: ahejlsberg

src/compiler/checker.ts

@@ -16604,7 +16604,8 @@ namespace ts {
                         if (t.flags & (TypeFlags.AnyOrUnknown | TypeFlags.InstantiableNonPrimitive | TypeFlags.Object | TypeFlags.Intersection) && t !== wildcardType && !isErrorType(t)) {
                             if (!type.declaration.nameType) {
                                 let constraint;
-                                if (isArrayType(t) || (t.flags & TypeFlags.Any) && (constraint = getConstraintOfTypeParameter(typeVariable)) && everyType(constraint, or(isArrayType, isTupleType))) {
+                                if (isArrayType(t) || t.flags & TypeFlags.Any && findResolutionCycleStartIndex(typeVariable, TypeSystemPropertyName.ImmediateBaseConstraint) < 0 &&
+                                    (constraint = getConstraintOfTypeParameter(typeVariable)) && everyType(constraint, or(isArrayType, isTupleType))) {
                                     return instantiateMappedArrayType(t, type, prependTypeMapping(typeVariable, t, mapper));
                                 }
                                 if (isGenericTupleType(t)) {

tests/baselines/reference/mappedTypeWithAny.errors.txt

@@ -67,4 +67,14 @@ tests/cases/conformance/types/mapped/mappedTypeWithAny.ts(53,5): error TS2322: T
     let def: [any, any] = stringifyPair(void 0 as any);
         ~~~
 !!! error TS2322: Type 'string[]' is not assignable to type '[any, any]'.
-!!! error TS2322:   Target requires 2 element(s) but source may have fewer.
+!!! error TS2322:   Target requires 2 element(s) but source may have fewer.
+    
+    // Repro from #46582
+    
+    type Evolvable<E extends Evolver> = {
+      [P in keyof E]: never;
+    };
+    type Evolver<T extends Evolvable<any> = any> = {
+      [key in keyof Partial<T>]: never;
+    };
+    

tests/baselines/reference/mappedTypeWithAny.js

@@ -51,7 +51,17 @@ declare function stringifyArray<T extends readonly any[]>(arr: T): { -readonly [
 let abc: any[] = stringifyArray(void 0 as any);
 
 declare function stringifyPair<T extends readonly [any, any]>(arr: T): { -readonly [K in keyof T]: string };
-let def: [any, any] = stringifyPair(void 0 as any);
+let def: [any, any] = stringifyPair(void 0 as any);
+
+// Repro from #46582
+
+type Evolvable<E extends Evolver> = {
+  [P in keyof E]: never;
+};
+type Evolver<T extends Evolvable<any> = any> = {
+  [key in keyof Partial<T>]: never;
+};
+
 
 //// [mappedTypeWithAny.js]
 "use strict";
@@ -110,3 +120,9 @@ declare function stringifyPair<T extends readonly [any, any]>(arr: T): {
     -readonly [K in keyof T]: string;
 };
 declare let def: [any, any];
+declare type Evolvable<E extends Evolver> = {
+    [P in keyof E]: never;
+};
+declare type Evolver<T extends Evolvable<any> = any> = {
+    [key in keyof Partial<T>]: never;
+};

tests/baselines/reference/mappedTypeWithAny.symbols

@@ -151,3 +151,27 @@ let def: [any, any] = stringifyPair(void 0 as any);
 >def : Symbol(def, Decl(mappedTypeWithAny.ts, 52, 3))
 >stringifyPair : Symbol(stringifyPair, Decl(mappedTypeWithAny.ts, 49, 47))
 
+// Repro from #46582
+
+type Evolvable<E extends Evolver> = {
+>Evolvable : Symbol(Evolvable, Decl(mappedTypeWithAny.ts, 52, 51))
+>E : Symbol(E, Decl(mappedTypeWithAny.ts, 56, 15))
+>Evolver : Symbol(Evolver, Decl(mappedTypeWithAny.ts, 58, 2))
+
+  [P in keyof E]: never;
+>P : Symbol(P, Decl(mappedTypeWithAny.ts, 57, 3))
+>E : Symbol(E, Decl(mappedTypeWithAny.ts, 56, 15))
+
+};
+type Evolver<T extends Evolvable<any> = any> = {
+>Evolver : Symbol(Evolver, Decl(mappedTypeWithAny.ts, 58, 2))
+>T : Symbol(T, Decl(mappedTypeWithAny.ts, 59, 13))
+>Evolvable : Symbol(Evolvable, Decl(mappedTypeWithAny.ts, 52, 51))
+
+  [key in keyof Partial<T>]: never;
+>key : Symbol(key, Decl(mappedTypeWithAny.ts, 60, 3))
+>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeWithAny.ts, 59, 13))
+
+};
+

tests/baselines/reference/mappedTypeWithAny.types

@@ -125,3 +125,16 @@ let def: [any, any] = stringifyPair(void 0 as any);
 >void 0 : undefined
 >0 : 0
 
+// Repro from #46582
+
+type Evolvable<E extends Evolver> = {
+>Evolvable : Evolvable<E>
+
+  [P in keyof E]: never;
+};
+type Evolver<T extends Evolvable<any> = any> = {
+>Evolver : Evolver<T>
+
+  [key in keyof Partial<T>]: never;
+};
+

tests/cases/conformance/types/mapped/mappedTypeWithAny.ts

@@ -53,4 +53,13 @@ declare function stringifyArray<T extends readonly any[]>(arr: T): { -readonly [
 let abc: any[] = stringifyArray(void 0 as any);
 
 declare function stringifyPair<T extends readonly [any, any]>(arr: T): { -readonly [K in keyof T]: string };
-let def: [any, any] = stringifyPair(void 0 as any);
+let def: [any, any] = stringifyPair(void 0 as any);
+
+// Repro from #46582
+
+type Evolvable<E extends Evolver> = {
+  [P in keyof E]: never;
+};
+type Evolver<T extends Evolvable<any> = any> = {
+  [key in keyof Partial<T>]: never;
+};