Reset type resolution stack when starting to compute variance

src/compiler/checker.ts

@@ -2156,6 +2156,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     var resolutionTargets: TypeSystemEntity[] = [];
     var resolutionResults: boolean[] = [];
     var resolutionPropertyNames: TypeSystemPropertyName[] = [];
+    var resolutionStart = 0;
+    var inVarianceComputation = false;
 
     var suggestionCount = 0;
     var maximumSuggestionCount = 10;
@@ -10105,7 +10107,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function findResolutionCycleStartIndex(target: TypeSystemEntity, propertyName: TypeSystemPropertyName): number {
-        for (let i = resolutionTargets.length - 1; i >= 0; i--) {
+        for (let i = resolutionTargets.length - 1; i >= resolutionStart; i--) {
             if (resolutionTargetHasProperty(resolutionTargets[i], resolutionPropertyNames[i])) {
                 return -1;
             }
@@ -22678,6 +22680,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         const links = getSymbolLinks(symbol);
         if (!links.variances) {
             tracing?.push(tracing.Phase.CheckTypes, "getVariancesWorker", { arity: typeParameters.length, id: getTypeId(getDeclaredTypeOfSymbol(symbol)) });
+            const oldVarianceComputation = inVarianceComputation;
+            if (!inVarianceComputation) {
+                inVarianceComputation = true;
+                resolutionStart = resolutionTargets.length;
+            }
             links.variances = emptyArray;
             const variances = [];
             for (const tp of typeParameters) {
@@ -22716,6 +22723,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 }
                 variances.push(variance);
             }
+            if (!oldVarianceComputation) {
+                inVarianceComputation = false;
+                resolutionStart = 0;
+            }
             links.variances = variances;
             tracing?.pop({ variances: variances.map(Debug.formatVariance) });
         }

tests/baselines/reference/classVarianceResolveCircularity.js → tests/baselines/reference/classVarianceResolveCircularity1.js

@@ -1,15 +1,15 @@
-//// [classVarianceResolveCircularity.ts]
+//// [classVarianceResolveCircularity1.ts]
 // Issue #52813
 
 class Bar<T> {
-    num!: number;    // Swap to remove error
+    num!: number;
     Value = callme(this).num;
     Field: number = callme(this).num;
 }
 declare function callme(x: Bar<any>): Bar<any>;
 declare function callme(x: object): string;
 
-//// [classVarianceResolveCircularity.js]
+//// [classVarianceResolveCircularity1.js]
 "use strict";
 // Issue #52813
 var Bar = /** @class */ (function () {

tests/baselines/reference/classVarianceResolveCircularity1.symbols

@@ -0,0 +1,34 @@
+=== tests/cases/compiler/classVarianceResolveCircularity1.ts ===
+// Issue #52813
+
+class Bar<T> {
+>Bar : Symbol(Bar, Decl(classVarianceResolveCircularity1.ts, 0, 0))
+>T : Symbol(T, Decl(classVarianceResolveCircularity1.ts, 2, 10))
+
+    num!: number;
+>num : Symbol(Bar.num, Decl(classVarianceResolveCircularity1.ts, 2, 14))
+
+    Value = callme(this).num;
+>Value : Symbol(Bar.Value, Decl(classVarianceResolveCircularity1.ts, 3, 17))
+>callme(this).num : Symbol(Bar.num, Decl(classVarianceResolveCircularity1.ts, 2, 14))
+>callme : Symbol(callme, Decl(classVarianceResolveCircularity1.ts, 6, 1), Decl(classVarianceResolveCircularity1.ts, 7, 47))
+>this : Symbol(Bar, Decl(classVarianceResolveCircularity1.ts, 0, 0))
+>num : Symbol(Bar.num, Decl(classVarianceResolveCircularity1.ts, 2, 14))
+
+    Field: number = callme(this).num;
+>Field : Symbol(Bar.Field, Decl(classVarianceResolveCircularity1.ts, 4, 29))
+>callme(this).num : Symbol(Bar.num, Decl(classVarianceResolveCircularity1.ts, 2, 14))
+>callme : Symbol(callme, Decl(classVarianceResolveCircularity1.ts, 6, 1), Decl(classVarianceResolveCircularity1.ts, 7, 47))
+>this : Symbol(Bar, Decl(classVarianceResolveCircularity1.ts, 0, 0))
+>num : Symbol(Bar.num, Decl(classVarianceResolveCircularity1.ts, 2, 14))
+}
+declare function callme(x: Bar<any>): Bar<any>;
+>callme : Symbol(callme, Decl(classVarianceResolveCircularity1.ts, 6, 1), Decl(classVarianceResolveCircularity1.ts, 7, 47))
+>x : Symbol(x, Decl(classVarianceResolveCircularity1.ts, 7, 24))
+>Bar : Symbol(Bar, Decl(classVarianceResolveCircularity1.ts, 0, 0))
+>Bar : Symbol(Bar, Decl(classVarianceResolveCircularity1.ts, 0, 0))
+
+declare function callme(x: object): string;
+>callme : Symbol(callme, Decl(classVarianceResolveCircularity1.ts, 6, 1), Decl(classVarianceResolveCircularity1.ts, 7, 47))
+>x : Symbol(x, Decl(classVarianceResolveCircularity1.ts, 8, 24))
+

tests/baselines/reference/classVarianceResolveCircularity.types → tests/baselines/reference/classVarianceResolveCircularity1.types

@@ -1,14 +1,14 @@
-=== tests/cases/compiler/classVarianceResolveCircularity.ts ===
+=== tests/cases/compiler/classVarianceResolveCircularity1.ts ===
 // Issue #52813
 
 class Bar<T> {
 >Bar : Bar<T>
 
-    num!: number;    // Swap to remove error
+    num!: number;
 >num : number
 
     Value = callme(this).num;
->Value : any
+>Value : number
 >callme(this).num : number
 >callme(this) : Bar<any>
 >callme : { (x: Bar<any>): Bar<any>; (x: object): string; }

tests/baselines/reference/classVarianceResolveCircularity2.js

@@ -0,0 +1,37 @@
+//// [classVarianceResolveCircularity2.ts]
+// Issue #52813
+
+export {};
+
+class Bar<T> {
+    num!: number;
+    Value = callme(new Foo(this)).bar.num;
+    Field: number = callme(new Foo(this)).bar.num;
+}
+declare function callme(x: Foo<any>): Foo<any>;
+declare function callme(x: object): string;
+
+class Foo<T> {
+    bar!: Bar<T>;
+    constructor(bar: Bar<T>) {
+        this.bar = bar;
+    }
+}
+
+//// [classVarianceResolveCircularity2.js]
+"use strict";
+// Issue #52813
+Object.defineProperty(exports, "__esModule", { value: true });
+var Bar = /** @class */ (function () {
+    function Bar() {
+        this.Value = callme(new Foo(this)).bar.num;
+        this.Field = callme(new Foo(this)).bar.num;
+    }
+    return Bar;
+}());
+var Foo = /** @class */ (function () {
+    function Foo(bar) {
+        this.bar = bar;
+    }
+    return Foo;
+}());

tests/baselines/reference/classVarianceResolveCircularity2.symbols

@@ -0,0 +1,63 @@
+=== tests/cases/compiler/classVarianceResolveCircularity2.ts ===
+// Issue #52813
+
+export {};
+
+class Bar<T> {
+>Bar : Symbol(Bar, Decl(classVarianceResolveCircularity2.ts, 2, 10))
+>T : Symbol(T, Decl(classVarianceResolveCircularity2.ts, 4, 10))
+
+    num!: number;
+>num : Symbol(Bar.num, Decl(classVarianceResolveCircularity2.ts, 4, 14))
+
+    Value = callme(new Foo(this)).bar.num;
+>Value : Symbol(Bar.Value, Decl(classVarianceResolveCircularity2.ts, 5, 17))
+>callme(new Foo(this)).bar.num : Symbol(Bar.num, Decl(classVarianceResolveCircularity2.ts, 4, 14))
+>callme(new Foo(this)).bar : Symbol(Foo.bar, Decl(classVarianceResolveCircularity2.ts, 12, 14))
+>callme : Symbol(callme, Decl(classVarianceResolveCircularity2.ts, 8, 1), Decl(classVarianceResolveCircularity2.ts, 9, 47))
+>Foo : Symbol(Foo, Decl(classVarianceResolveCircularity2.ts, 10, 43))
+>this : Symbol(Bar, Decl(classVarianceResolveCircularity2.ts, 2, 10))
+>bar : Symbol(Foo.bar, Decl(classVarianceResolveCircularity2.ts, 12, 14))
+>num : Symbol(Bar.num, Decl(classVarianceResolveCircularity2.ts, 4, 14))
+
+    Field: number = callme(new Foo(this)).bar.num;
+>Field : Symbol(Bar.Field, Decl(classVarianceResolveCircularity2.ts, 6, 42))
+>callme(new Foo(this)).bar.num : Symbol(Bar.num, Decl(classVarianceResolveCircularity2.ts, 4, 14))
+>callme(new Foo(this)).bar : Symbol(Foo.bar, Decl(classVarianceResolveCircularity2.ts, 12, 14))
+>callme : Symbol(callme, Decl(classVarianceResolveCircularity2.ts, 8, 1), Decl(classVarianceResolveCircularity2.ts, 9, 47))
+>Foo : Symbol(Foo, Decl(classVarianceResolveCircularity2.ts, 10, 43))
+>this : Symbol(Bar, Decl(classVarianceResolveCircularity2.ts, 2, 10))
+>bar : Symbol(Foo.bar, Decl(classVarianceResolveCircularity2.ts, 12, 14))
+>num : Symbol(Bar.num, Decl(classVarianceResolveCircularity2.ts, 4, 14))
+}
+declare function callme(x: Foo<any>): Foo<any>;
+>callme : Symbol(callme, Decl(classVarianceResolveCircularity2.ts, 8, 1), Decl(classVarianceResolveCircularity2.ts, 9, 47))
+>x : Symbol(x, Decl(classVarianceResolveCircularity2.ts, 9, 24))
+>Foo : Symbol(Foo, Decl(classVarianceResolveCircularity2.ts, 10, 43))
+>Foo : Symbol(Foo, Decl(classVarianceResolveCircularity2.ts, 10, 43))
+
+declare function callme(x: object): string;
+>callme : Symbol(callme, Decl(classVarianceResolveCircularity2.ts, 8, 1), Decl(classVarianceResolveCircularity2.ts, 9, 47))
+>x : Symbol(x, Decl(classVarianceResolveCircularity2.ts, 10, 24))
+
+class Foo<T> {
+>Foo : Symbol(Foo, Decl(classVarianceResolveCircularity2.ts, 10, 43))
+>T : Symbol(T, Decl(classVarianceResolveCircularity2.ts, 12, 10))
+
+    bar!: Bar<T>;
+>bar : Symbol(Foo.bar, Decl(classVarianceResolveCircularity2.ts, 12, 14))
+>Bar : Symbol(Bar, Decl(classVarianceResolveCircularity2.ts, 2, 10))
+>T : Symbol(T, Decl(classVarianceResolveCircularity2.ts, 12, 10))
+
+    constructor(bar: Bar<T>) {
+>bar : Symbol(bar, Decl(classVarianceResolveCircularity2.ts, 14, 16))
+>Bar : Symbol(Bar, Decl(classVarianceResolveCircularity2.ts, 2, 10))
+>T : Symbol(T, Decl(classVarianceResolveCircularity2.ts, 12, 10))
+
+        this.bar = bar;
+>this.bar : Symbol(Foo.bar, Decl(classVarianceResolveCircularity2.ts, 12, 14))
+>this : Symbol(Foo, Decl(classVarianceResolveCircularity2.ts, 10, 43))
+>bar : Symbol(Foo.bar, Decl(classVarianceResolveCircularity2.ts, 12, 14))
+>bar : Symbol(bar, Decl(classVarianceResolveCircularity2.ts, 14, 16))
+    }
+}

tests/baselines/reference/classVarianceResolveCircularity2.types

@@ -0,0 +1,60 @@
+=== tests/cases/compiler/classVarianceResolveCircularity2.ts ===
+// Issue #52813
+
+export {};
+
+class Bar<T> {
+>Bar : Bar<T>
+
+    num!: number;
+>num : number
+
+    Value = callme(new Foo(this)).bar.num;
+>Value : number
+>callme(new Foo(this)).bar.num : number
+>callme(new Foo(this)).bar : Bar<any>
+>callme(new Foo(this)) : Foo<any>
+>callme : { (x: Foo<any>): Foo<any>; (x: object): string; }
+>new Foo(this) : Foo<T>
+>Foo : typeof Foo
+>this : this
+>bar : Bar<any>
+>num : number
+
+    Field: number = callme(new Foo(this)).bar.num;
+>Field : number
+>callme(new Foo(this)).bar.num : number
+>callme(new Foo(this)).bar : Bar<any>
+>callme(new Foo(this)) : Foo<any>
+>callme : { (x: Foo<any>): Foo<any>; (x: object): string; }
+>new Foo(this) : Foo<T>
+>Foo : typeof Foo
+>this : this
+>bar : Bar<any>
+>num : number
+}
+declare function callme(x: Foo<any>): Foo<any>;
+>callme : { (x: Foo<any>): Foo<any>; (x: object): string; }
+>x : Foo<any>
+
+declare function callme(x: object): string;
+>callme : { (x: Foo<any>): Foo<any>; (x: object): string; }
+>x : object
+
+class Foo<T> {
+>Foo : Foo<T>
+
+    bar!: Bar<T>;
+>bar : Bar<T>
+
+    constructor(bar: Bar<T>) {
+>bar : Bar<T>
+
+        this.bar = bar;
+>this.bar = bar : Bar<T>
+>this.bar : Bar<T>
+>this : this
+>bar : Bar<T>
+>bar : Bar<T>
+    }
+}

tests/cases/compiler/classVarianceResolveCircularity.ts → tests/cases/compiler/classVarianceResolveCircularity1.ts

@@ -3,7 +3,7 @@
 // Issue #52813
 
 class Bar<T> {
-    num!: number;    // Swap to remove error
+    num!: number;
     Value = callme(this).num;
     Field: number = callme(this).num;
 }

tests/cases/compiler/classVarianceResolveCircularity2.ts

@@ -0,0 +1,20 @@
+// @strict: true
+
+// Issue #52813
+
+export {};
+
+class Bar<T> {
+    num!: number;
+    Value = callme(new Foo(this)).bar.num;
+    Field: number = callme(new Foo(this)).bar.num;
+}
+declare function callme(x: Foo<any>): Foo<any>;
+declare function callme(x: object): string;
+
+class Foo<T> {
+    bar!: Bar<T>;
+    constructor(bar: Bar<T>) {
+        this.bar = bar;
+    }
+}