Add regression test

tests/baselines/reference/circularInferredTypeOfVariable.js

@@ -0,0 +1,44 @@
+//// [circularInferredTypeOfVariable.ts]
+
+// Repro from #14428
+
+(async () => {
+    function foo(p: string[]): string[] {
+        return [];
+    }
+
+    function bar(p: string[]): string[] {
+        return [];
+    }
+
+    let a1: string[] | undefined = [];
+
+    while (true) {
+        let a2 = foo(a1!);
+        a1 = await bar(a2);
+    }
+});
+
+//// [circularInferredTypeOfVariable.js]
+// Repro from #14428
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+(() => __awaiter(this, void 0, void 0, function* () {
+    function foo(p) {
+        return [];
+    }
+    function bar(p) {
+        return [];
+    }
+    let a1 = [];
+    while (true) {
+        let a2 = foo(a1);
+        a1 = yield bar(a2);
+    }
+}));

tests/baselines/reference/circularInferredTypeOfVariable.symbols

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+=== tests/cases/compiler/circularInferredTypeOfVariable.ts ===
+
+// Repro from #14428
+
+(async () => {
+    function foo(p: string[]): string[] {
+>foo : Symbol(foo, Decl(circularInferredTypeOfVariable.ts, 3, 14))
+>p : Symbol(p, Decl(circularInferredTypeOfVariable.ts, 4, 17))
+
+        return [];
+    }
+
+    function bar(p: string[]): string[] {
+>bar : Symbol(bar, Decl(circularInferredTypeOfVariable.ts, 6, 5))
+>p : Symbol(p, Decl(circularInferredTypeOfVariable.ts, 8, 17))
+
+        return [];
+    }
+
+    let a1: string[] | undefined = [];
+>a1 : Symbol(a1, Decl(circularInferredTypeOfVariable.ts, 12, 7))
+
+    while (true) {
+        let a2 = foo(a1!);
+>a2 : Symbol(a2, Decl(circularInferredTypeOfVariable.ts, 15, 11))
+>foo : Symbol(foo, Decl(circularInferredTypeOfVariable.ts, 3, 14))
+>a1 : Symbol(a1, Decl(circularInferredTypeOfVariable.ts, 12, 7))
+
+        a1 = await bar(a2);
+>a1 : Symbol(a1, Decl(circularInferredTypeOfVariable.ts, 12, 7))
+>bar : Symbol(bar, Decl(circularInferredTypeOfVariable.ts, 6, 5))
+>a2 : Symbol(a2, Decl(circularInferredTypeOfVariable.ts, 15, 11))
+    }
+});

tests/baselines/reference/circularInferredTypeOfVariable.types

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+=== tests/cases/compiler/circularInferredTypeOfVariable.ts ===
+
+// Repro from #14428
+
+(async () => {
+>(async () => {    function foo(p: string[]): string[] {        return [];    }    function bar(p: string[]): string[] {        return [];    }    let a1: string[] | undefined = [];    while (true) {        let a2 = foo(a1!);        a1 = await bar(a2);    }}) : () => Promise<never>
+>async () => {    function foo(p: string[]): string[] {        return [];    }    function bar(p: string[]): string[] {        return [];    }    let a1: string[] | undefined = [];    while (true) {        let a2 = foo(a1!);        a1 = await bar(a2);    }} : () => Promise<never>
+
+    function foo(p: string[]): string[] {
+>foo : (p: string[]) => string[]
+>p : string[]
+
+        return [];
+>[] : undefined[]
+    }
+
+    function bar(p: string[]): string[] {
+>bar : (p: string[]) => string[]
+>p : string[]
+
+        return [];
+>[] : undefined[]
+    }
+
+    let a1: string[] | undefined = [];
+>a1 : string[]
+>[] : undefined[]
+
+    while (true) {
+>true : true
+
+        let a2 = foo(a1!);
+>a2 : string[]
+>foo(a1!) : string[]
+>foo : (p: string[]) => string[]
+>a1! : string[]
+>a1 : string[]
+
+        a1 = await bar(a2);
+>a1 = await bar(a2) : string[]
+>a1 : string[]
+>await bar(a2) : string[]
+>bar(a2) : string[]
+>bar : (p: string[]) => string[]
+>a2 : string[]
+    }
+});

tests/cases/compiler/circularInferredTypeOfVariable.ts

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+// @target: es6
+
+// Repro from #14428
+
+(async () => {
+    function foo(p: string[]): string[] {
+        return [];
+    }
+
+    function bar(p: string[]): string[] {
+        return [];
+    }
+
+    let a1: string[] | undefined = [];
+
+    while (true) {
+        let a2 = foo(a1!);
+        a1 = await bar(a2);
+    }
+});