Types that extend Array or ReadonlyArray are automatically array-like

Author: andrewbranch

src/compiler/checker.ts

@@ -19703,7 +19703,13 @@ namespace ts {
         function isArrayLikeType(type: Type): boolean {
             // A type is array-like if it is a reference to the global Array or global ReadonlyArray type,
             // or if it is not the undefined or null type and if it is assignable to ReadonlyArray<any>
-            return isArrayType(type) || !(type.flags & TypeFlags.Nullable) && isTypeAssignableTo(type, anyReadonlyArrayType);
+            return isArrayType(type) || hasArrayOrReadonlyArrayBaseType(type) || !(type.flags & TypeFlags.Nullable) && isTypeAssignableTo(type, anyReadonlyArrayType);
+        }
+
+        function hasArrayOrReadonlyArrayBaseType(type: Type): boolean {
+            return !!(getObjectFlags(type) & ObjectFlags.Reference)
+                && !!(getObjectFlags((type as TypeReference).target) & ObjectFlags.ClassOrInterface)
+                && some(getBaseTypes((type as TypeReference).target as InterfaceType), isArrayType);
         }
 
         function isEmptyArrayLiteralType(type: Type): boolean {

tests/baselines/reference/excessiveStackDepthFlatArray.js

@@ -0,0 +1,19 @@
+//// [excessiveStackDepthFlatArray.ts]
+interface MiddlewareArray<T> extends Array<T> {}
+declare function configureStore(options: { middleware: MiddlewareArray<any> }): void;
+
+declare const defaultMiddleware: MiddlewareArray<any>;
+configureStore({
+  middleware: [...defaultMiddleware], // Should not error
+});
+
+
+//// [excessiveStackDepthFlatArray.js]
+var __spreadArray = (this && this.__spreadArray) || function (to, from) {
+    for (var i = 0, il = from.length, j = to.length; i < il; i++, j++)
+        to[j] = from[i];
+    return to;
+};
+configureStore({
+    middleware: __spreadArray([], defaultMiddleware)
+});

tests/baselines/reference/excessiveStackDepthFlatArray.symbols

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/excessiveStackDepthFlatArray.ts ===
+interface MiddlewareArray<T> extends Array<T> {}
+>MiddlewareArray : Symbol(MiddlewareArray, Decl(excessiveStackDepthFlatArray.ts, 0, 0))
+>T : Symbol(T, Decl(excessiveStackDepthFlatArray.ts, 0, 26))
+>Array : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --) ... and 2 more)
+>T : Symbol(T, Decl(excessiveStackDepthFlatArray.ts, 0, 26))
+
+declare function configureStore(options: { middleware: MiddlewareArray<any> }): void;
+>configureStore : Symbol(configureStore, Decl(excessiveStackDepthFlatArray.ts, 0, 48))
+>options : Symbol(options, Decl(excessiveStackDepthFlatArray.ts, 1, 32))
+>middleware : Symbol(middleware, Decl(excessiveStackDepthFlatArray.ts, 1, 42))
+>MiddlewareArray : Symbol(MiddlewareArray, Decl(excessiveStackDepthFlatArray.ts, 0, 0))
+
+declare const defaultMiddleware: MiddlewareArray<any>;
+>defaultMiddleware : Symbol(defaultMiddleware, Decl(excessiveStackDepthFlatArray.ts, 3, 13))
+>MiddlewareArray : Symbol(MiddlewareArray, Decl(excessiveStackDepthFlatArray.ts, 0, 0))
+
+configureStore({
+>configureStore : Symbol(configureStore, Decl(excessiveStackDepthFlatArray.ts, 0, 48))
+
+  middleware: [...defaultMiddleware], // Should not error
+>middleware : Symbol(middleware, Decl(excessiveStackDepthFlatArray.ts, 4, 16))
+>defaultMiddleware : Symbol(defaultMiddleware, Decl(excessiveStackDepthFlatArray.ts, 3, 13))
+
+});
+

tests/baselines/reference/excessiveStackDepthFlatArray.types

@@ -0,0 +1,23 @@
+=== tests/cases/compiler/excessiveStackDepthFlatArray.ts ===
+interface MiddlewareArray<T> extends Array<T> {}
+declare function configureStore(options: { middleware: MiddlewareArray<any> }): void;
+>configureStore : (options: {    middleware: MiddlewareArray<any>;}) => void
+>options : { middleware: MiddlewareArray<any>; }
+>middleware : MiddlewareArray<any>
+
+declare const defaultMiddleware: MiddlewareArray<any>;
+>defaultMiddleware : MiddlewareArray<any>
+
+configureStore({
+>configureStore({  middleware: [...defaultMiddleware], // Should not error}) : void
+>configureStore : (options: { middleware: MiddlewareArray<any>; }) => void
+>{  middleware: [...defaultMiddleware], // Should not error} : { middleware: any[]; }
+
+  middleware: [...defaultMiddleware], // Should not error
+>middleware : any[]
+>[...defaultMiddleware] : any[]
+>...defaultMiddleware : any
+>defaultMiddleware : MiddlewareArray<any>
+
+});
+

tests/cases/compiler/excessiveStackDepthFlatArray.ts

@@ -0,0 +1,9 @@
+// @lib: es2019
+
+interface MiddlewareArray<T> extends Array<T> {}
+declare function configureStore(options: { middleware: MiddlewareArray<any> }): void;
+
+declare const defaultMiddleware: MiddlewareArray<any>;
+configureStore({
+  middleware: [...defaultMiddleware], // Should not error
+});