Add regression test

Author: ahejlsberg

tests/baselines/reference/controlFlowArrays.js

@@ -176,7 +176,16 @@ function f18() {
     x.unshift("hello");
     x[2] = true;
     return x;  // (string | number | boolean)[]
-}
+}
+
+// Repro from #39470
+
+declare function foo(arg: { val: number }[]): void;
+
+let arr = []
+arr.push({ val: 1, bar: 2 });
+foo(arr);
+
 
 //// [controlFlowArrays.js]
 function f1() {
@@ -340,3 +349,6 @@ function f18() {
     x[2] = true;
     return x; // (string | number | boolean)[]
 }
+var arr = [];
+arr.push({ val: 1, bar: 2 });
+foo(arr);

tests/baselines/reference/controlFlowArrays.symbols

@@ -467,3 +467,25 @@ function f18() {
     return x;  // (string | number | boolean)[]
 >x : Symbol(x, Decl(controlFlowArrays.ts, 172, 7))
 }
+
+// Repro from #39470
+
+declare function foo(arg: { val: number }[]): void;
+>foo : Symbol(foo, Decl(controlFlowArrays.ts, 177, 1))
+>arg : Symbol(arg, Decl(controlFlowArrays.ts, 181, 21))
+>val : Symbol(val, Decl(controlFlowArrays.ts, 181, 27))
+
+let arr = []
+>arr : Symbol(arr, Decl(controlFlowArrays.ts, 183, 3))
+
+arr.push({ val: 1, bar: 2 });
+>arr.push : Symbol(Array.push, Decl(lib.es5.d.ts, --, --))
+>arr : Symbol(arr, Decl(controlFlowArrays.ts, 183, 3))
+>push : Symbol(Array.push, Decl(lib.es5.d.ts, --, --))
+>val : Symbol(val, Decl(controlFlowArrays.ts, 184, 10))
+>bar : Symbol(bar, Decl(controlFlowArrays.ts, 184, 18))
+
+foo(arr);
+>foo : Symbol(foo, Decl(controlFlowArrays.ts, 177, 1))
+>arr : Symbol(arr, Decl(controlFlowArrays.ts, 183, 3))
+

tests/baselines/reference/controlFlowArrays.types

@@ -612,3 +612,31 @@ function f18() {
     return x;  // (string | number | boolean)[]
 >x : (string | number | boolean)[]
 }
+
+// Repro from #39470
+
+declare function foo(arg: { val: number }[]): void;
+>foo : (arg: {    val: number;}[]) => void
+>arg : { val: number; }[]
+>val : number
+
+let arr = []
+>arr : any[]
+>[] : never[]
+
+arr.push({ val: 1, bar: 2 });
+>arr.push({ val: 1, bar: 2 }) : number
+>arr.push : (...items: any[]) => number
+>arr : any[]
+>push : (...items: any[]) => number
+>{ val: 1, bar: 2 } : { val: number; bar: number; }
+>val : number
+>1 : 1
+>bar : number
+>2 : 2
+
+foo(arr);
+>foo(arr) : void
+>foo : (arg: { val: number; }[]) => void
+>arr : { val: number; bar: number; }[]
+

tests/cases/compiler/controlFlowArrays.ts

@@ -178,4 +178,12 @@ function f18() {
     x.unshift("hello");
     x[2] = true;
     return x;  // (string | number | boolean)[]
-}
+}
+
+// Repro from #39470
+
+declare function foo(arg: { val: number }[]): void;
+
+let arr = []
+arr.push({ val: 1, bar: 2 });
+foo(arr);