Remove special any assignability for numeric index signatures (#41660)

* Only enable special assignability rule on string index signatures to 'any'.

* Accepted baselines.

* Added test.

* Accepted baselines.

* Renamed test files.

* Add non-erroring version of bclas'subClassThisTypeAssignable01.ts'

* Accepted baselines.

Co-authored-by: TypeScript Bot <typescriptbot@microsoft.com>

Author: DanielRosenwasser

src/compiler/checker.ts

@@ -18948,7 +18948,7 @@ namespace ts {
                     return indexTypesIdenticalTo(source, target, kind);
                 }
                 const targetType = getIndexTypeOfType(target, kind);
-                if (!targetType || targetType.flags & TypeFlags.Any && !sourceIsPrimitive) {
+                if (!targetType || targetType.flags & TypeFlags.Any && !sourceIsPrimitive && kind === IndexKind.String) {
                     // Index signature of type any permits assignment from everything but primitives
                     return Ternary.True;
                 }

tests/baselines/reference/functionAssignabilityWithArrayLike01(strict=false).errors.txt

@@ -0,0 +1,10 @@
+tests/cases/compiler/functionAssignabilityWithArrayLike01.ts(2,7): error TS2322: Type '() => void' is not assignable to type 'ArrayLike<any>'.
+  Index signature is missing in type '() => void'.
+
+
+==== tests/cases/compiler/functionAssignabilityWithArrayLike01.ts (1 errors) ====
+    function func() {}
+    const array: ArrayLike<any> = func;
+          ~~~~~
+!!! error TS2322: Type '() => void' is not assignable to type 'ArrayLike<any>'.
+!!! error TS2322:   Index signature is missing in type '() => void'.

tests/baselines/reference/functionAssignabilityWithArrayLike01(strict=false).js

@@ -0,0 +1,7 @@
+//// [functionAssignabilityWithArrayLike01.ts]
+function func() {}
+const array: ArrayLike<any> = func;
+
+//// [functionAssignabilityWithArrayLike01.js]
+function func() { }
+var array = func;

tests/baselines/reference/functionAssignabilityWithArrayLike01(strict=false).symbols

@@ -0,0 +1,9 @@
+=== tests/cases/compiler/functionAssignabilityWithArrayLike01.ts ===
+function func() {}
+>func : Symbol(func, Decl(functionAssignabilityWithArrayLike01.ts, 0, 0))
+
+const array: ArrayLike<any> = func;
+>array : Symbol(array, Decl(functionAssignabilityWithArrayLike01.ts, 1, 5))
+>ArrayLike : Symbol(ArrayLike, Decl(lib.es5.d.ts, --, --))
+>func : Symbol(func, Decl(functionAssignabilityWithArrayLike01.ts, 0, 0))
+

tests/baselines/reference/functionAssignabilityWithArrayLike01(strict=false).types

@@ -0,0 +1,8 @@
+=== tests/cases/compiler/functionAssignabilityWithArrayLike01.ts ===
+function func() {}
+>func : () => void
+
+const array: ArrayLike<any> = func;
+>array : ArrayLike<any>
+>func : () => void
+

tests/baselines/reference/functionAssignabilityWithArrayLike01(strict=true).errors.txt

@@ -0,0 +1,10 @@
+tests/cases/compiler/functionAssignabilityWithArrayLike01.ts(2,7): error TS2322: Type '() => void' is not assignable to type 'ArrayLike<any>'.
+  Index signature is missing in type '() => void'.
+
+
+==== tests/cases/compiler/functionAssignabilityWithArrayLike01.ts (1 errors) ====
+    function func() {}
+    const array: ArrayLike<any> = func;
+          ~~~~~
+!!! error TS2322: Type '() => void' is not assignable to type 'ArrayLike<any>'.
+!!! error TS2322:   Index signature is missing in type '() => void'.

tests/baselines/reference/functionAssignabilityWithArrayLike01(strict=true).js

@@ -0,0 +1,8 @@
+//// [functionAssignabilityWithArrayLike01.ts]
+function func() {}
+const array: ArrayLike<any> = func;
+
+//// [functionAssignabilityWithArrayLike01.js]
+"use strict";
+function func() { }
+var array = func;

tests/baselines/reference/functionAssignabilityWithArrayLike01(strict=true).symbols

@@ -0,0 +1,9 @@
+=== tests/cases/compiler/functionAssignabilityWithArrayLike01.ts ===
+function func() {}
+>func : Symbol(func, Decl(functionAssignabilityWithArrayLike01.ts, 0, 0))
+
+const array: ArrayLike<any> = func;
+>array : Symbol(array, Decl(functionAssignabilityWithArrayLike01.ts, 1, 5))
+>ArrayLike : Symbol(ArrayLike, Decl(lib.es5.d.ts, --, --))
+>func : Symbol(func, Decl(functionAssignabilityWithArrayLike01.ts, 0, 0))
+

tests/baselines/reference/functionAssignabilityWithArrayLike01(strict=true).types

@@ -0,0 +1,8 @@
+=== tests/cases/compiler/functionAssignabilityWithArrayLike01.ts ===
+function func() {}
+>func : () => void
+
+const array: ArrayLike<any> = func;
+>array : ArrayLike<any>
+>func : () => void
+