Restrict spreading for Instantiable Type with non object constraint

src/compiler/checker.ts

@@ -19222,6 +19222,12 @@ namespace ts {
         }
 
         function isValidSpreadType(type: Type): boolean {
+            if (type.flags & TypeFlags.Instantiable) {
+                const constraint = getBaseConstraintOfType(type);
+                if (constraint !== undefined) {
+                    return isValidSpreadType(constraint);
+                }
+            }
             return !!(type.flags & (TypeFlags.AnyOrUnknown | TypeFlags.NonPrimitive | TypeFlags.Object | TypeFlags.InstantiableNonPrimitive) ||
                 getFalsyFlags(type) & TypeFlags.DefinitelyFalsy && isValidSpreadType(removeDefinitelyFalsyTypes(type)) ||
                 type.flags & TypeFlags.UnionOrIntersection && every((<UnionOrIntersectionType>type).types, isValidSpreadType));

tests/baselines/reference/restInvalidArgumentType.errors.txt

@@ -1,3 +1,4 @@
+tests/cases/compiler/restInvalidArgumentType.ts(30,13): error TS2700: Rest types may only be created from object types.
 tests/cases/compiler/restInvalidArgumentType.ts(31,13): error TS2700: Rest types may only be created from object types.
 tests/cases/compiler/restInvalidArgumentType.ts(37,13): error TS2700: Rest types may only be created from object types.
 tests/cases/compiler/restInvalidArgumentType.ts(40,13): error TS2700: Rest types may only be created from object types.
@@ -10,7 +11,7 @@ tests/cases/compiler/restInvalidArgumentType.ts(51,13): error TS2700: Rest types
 tests/cases/compiler/restInvalidArgumentType.ts(53,13): error TS2700: Rest types may only be created from object types.
 
 
-==== tests/cases/compiler/restInvalidArgumentType.ts (10 errors) ====
+==== tests/cases/compiler/restInvalidArgumentType.ts (11 errors) ====
     enum E { v1, v2 };
 
     function f<T extends { b: string }>(p1: T, p2: T[]) {
@@ -41,6 +42,8 @@ tests/cases/compiler/restInvalidArgumentType.ts(53,13): error TS2700: Rest types
         var {...r2} = p2;   // OK
         var {...r3} = t;   // Error, generic type paramter
         var {...r4} = i;   // Error, index access
+                ~~
+!!! error TS2700: Rest types may only be created from object types.
         var {...r5} = k;   // Error, index
                 ~~
 !!! error TS2700: Rest types may only be created from object types.

tests/baselines/reference/restInvalidArgumentType.types

@@ -79,7 +79,7 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
 >t : T
 
     var {...r4} = i;   // Error, index access
->r4 : T["b"]
+>r4 : any
 >i : T["b"]
 
     var {...r5} = k;   // Error, index

tests/baselines/reference/spreadInvalidArgumentType.errors.txt

@@ -1,3 +1,4 @@
+tests/cases/compiler/spreadInvalidArgumentType.ts(33,16): error TS2698: Spread types may only be created from object types.
 tests/cases/compiler/spreadInvalidArgumentType.ts(34,16): error TS2698: Spread types may only be created from object types.
 tests/cases/compiler/spreadInvalidArgumentType.ts(39,16): error TS2698: Spread types may only be created from object types.
 tests/cases/compiler/spreadInvalidArgumentType.ts(42,17): error TS2698: Spread types may only be created from object types.
@@ -10,7 +11,7 @@ tests/cases/compiler/spreadInvalidArgumentType.ts(53,17): error TS2698: Spread t
 tests/cases/compiler/spreadInvalidArgumentType.ts(55,17): error TS2698: Spread types may only be created from object types.
 
 
-==== tests/cases/compiler/spreadInvalidArgumentType.ts (10 errors) ====
+==== tests/cases/compiler/spreadInvalidArgumentType.ts (11 errors) ====
     enum E { v1, v2 };
 
     function f<T extends { b: string }>(p1: T, p2: T[]) {
@@ -43,7 +44,9 @@ tests/cases/compiler/spreadInvalidArgumentType.ts(55,17): error TS2698: Spread t
         var o1 = { ...p1 };  // OK, generic type paramterre
         var o2 = { ...p2 };  // OK
         var o3 = { ...t };   // OK, generic type paramter
-        var o4 = { ...i };   // OK, index access
+        var o4 = { ...i };   // Error, index access
+                   ~~~~
+!!! error TS2698: Spread types may only be created from object types.
         var o5 = { ...k };   // Error, index
                    ~~~~
 !!! error TS2698: Spread types may only be created from object types.

tests/baselines/reference/spreadInvalidArgumentType.js

@@ -31,7 +31,7 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
     var o1 = { ...p1 };  // OK, generic type paramterre
     var o2 = { ...p2 };  // OK
     var o3 = { ...t };   // OK, generic type paramter
-    var o4 = { ...i };   // OK, index access
+    var o4 = { ...i };   // Error, index access
     var o5 = { ...k };   // Error, index
     var o6 = { ...mapped_generic }; // OK, generic mapped object type
     var o7 = { ...mapped };  // OK, non-generic mapped type
@@ -96,7 +96,7 @@ function f(p1, p2) {
     var o1 = __assign({}, p1); // OK, generic type paramterre
     var o2 = __assign({}, p2); // OK
     var o3 = __assign({}, t); // OK, generic type paramter
-    var o4 = __assign({}, i); // OK, index access
+    var o4 = __assign({}, i); // Error, index access
     var o5 = __assign({}, k); // Error, index
     var o6 = __assign({}, mapped_generic); // OK, generic mapped object type
     var o7 = __assign({}, mapped); // OK, non-generic mapped type

tests/baselines/reference/spreadInvalidArgumentType.symbols

@@ -94,7 +94,7 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
 >o3 : Symbol(o3, Decl(spreadInvalidArgumentType.ts, 31, 7))
 >t : Symbol(t, Decl(spreadInvalidArgumentType.ts, 3, 7))
 
-    var o4 = { ...i };   // OK, index access
+    var o4 = { ...i };   // Error, index access
 >o4 : Symbol(o4, Decl(spreadInvalidArgumentType.ts, 32, 7))
 >i : Symbol(i, Decl(spreadInvalidArgumentType.ts, 5, 7))
 

tests/baselines/reference/spreadInvalidArgumentType.types

@@ -82,9 +82,9 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
 >{ ...t } : T
 >t : T
 
-    var o4 = { ...i };   // OK, index access
->o4 : T["b"]
->{ ...i } : T["b"]
+    var o4 = { ...i };   // Error, index access
+>o4 : any
+>{ ...i } : any
 >i : T["b"]
 
     var o5 = { ...k };   // Error, index

tests/baselines/reference/spreadTypeVariable.errors.txt

@@ -0,0 +1,37 @@
+tests/cases/conformance/types/spread/spreadTypeVariable.ts(2,12): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/spreadTypeVariable.ts(10,12): error TS2698: Spread types may only be created from object types.
+tests/cases/conformance/types/spread/spreadTypeVariable.ts(14,12): error TS2698: Spread types may only be created from object types.
+
+
+==== tests/cases/conformance/types/spread/spreadTypeVariable.ts (3 errors) ====
+    function f1<T extends number>(arg: T) {
+      return { ...arg };
+               ~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
+    }
+
+    function f2<T extends string[]>(arg: T) {
+      return { ...arg }
+    }
+
+    function f3<T extends number | string[]>(arg: T) {
+      return { ...arg }
+               ~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
+    }
+
+    function f4<T extends number | { [key: string]: any }>(arg: T) {
+      return { ...arg }
+               ~~~~~~
+!!! error TS2698: Spread types may only be created from object types.
+    }
+
+    function f5<T extends string[] | { [key: string]: any }>(arg: T) {
+      return { ...arg }
+    }
+
+    function f6<T>(arg: T) {
+      return { ...arg }
+    }
+
+

tests/baselines/reference/spreadTypeVariable.js

@@ -0,0 +1,57 @@
+//// [spreadTypeVariable.ts]
+function f1<T extends number>(arg: T) {
+  return { ...arg };
+}
+
+function f2<T extends string[]>(arg: T) {
+  return { ...arg }
+}
+
+function f3<T extends number | string[]>(arg: T) {
+  return { ...arg }
+}
+
+function f4<T extends number | { [key: string]: any }>(arg: T) {
+  return { ...arg }
+}
+
+function f5<T extends string[] | { [key: string]: any }>(arg: T) {
+  return { ...arg }
+}
+
+function f6<T>(arg: T) {
+  return { ...arg }
+}
+
+
+
+//// [spreadTypeVariable.js]
+var __assign = (this && this.__assign) || function () {
+    __assign = Object.assign || function(t) {
+        for (var s, i = 1, n = arguments.length; i < n; i++) {
+            s = arguments[i];
+            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+                t[p] = s[p];
+        }
+        return t;
+    };
+    return __assign.apply(this, arguments);
+};
+function f1(arg) {
+    return __assign({}, arg);
+}
+function f2(arg) {
+    return __assign({}, arg);
+}
+function f3(arg) {
+    return __assign({}, arg);
+}
+function f4(arg) {
+    return __assign({}, arg);
+}
+function f5(arg) {
+    return __assign({}, arg);
+}
+function f6(arg) {
+    return __assign({}, arg);
+}

tests/baselines/reference/spreadTypeVariable.symbols

@@ -0,0 +1,64 @@
+=== tests/cases/conformance/types/spread/spreadTypeVariable.ts ===
+function f1<T extends number>(arg: T) {
+>f1 : Symbol(f1, Decl(spreadTypeVariable.ts, 0, 0))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 0, 12))
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 0, 30))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 0, 12))
+
+  return { ...arg };
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 0, 30))
+}
+
+function f2<T extends string[]>(arg: T) {
+>f2 : Symbol(f2, Decl(spreadTypeVariable.ts, 2, 1))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 4, 12))
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 4, 32))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 4, 12))
+
+  return { ...arg }
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 4, 32))
+}
+
+function f3<T extends number | string[]>(arg: T) {
+>f3 : Symbol(f3, Decl(spreadTypeVariable.ts, 6, 1))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 8, 12))
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 8, 41))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 8, 12))
+
+  return { ...arg }
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 8, 41))
+}
+
+function f4<T extends number | { [key: string]: any }>(arg: T) {
+>f4 : Symbol(f4, Decl(spreadTypeVariable.ts, 10, 1))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 12, 12))
+>key : Symbol(key, Decl(spreadTypeVariable.ts, 12, 34))
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 12, 55))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 12, 12))
+
+  return { ...arg }
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 12, 55))
+}
+
+function f5<T extends string[] | { [key: string]: any }>(arg: T) {
+>f5 : Symbol(f5, Decl(spreadTypeVariable.ts, 14, 1))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 16, 12))
+>key : Symbol(key, Decl(spreadTypeVariable.ts, 16, 36))
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 16, 57))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 16, 12))
+
+  return { ...arg }
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 16, 57))
+}
+
+function f6<T>(arg: T) {
+>f6 : Symbol(f6, Decl(spreadTypeVariable.ts, 18, 1))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 20, 12))
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 20, 15))
+>T : Symbol(T, Decl(spreadTypeVariable.ts, 20, 12))
+
+  return { ...arg }
+>arg : Symbol(arg, Decl(spreadTypeVariable.ts, 20, 15))
+}
+
+

tests/baselines/reference/spreadTypeVariable.types

@@ -0,0 +1,58 @@
+=== tests/cases/conformance/types/spread/spreadTypeVariable.ts ===
+function f1<T extends number>(arg: T) {
+>f1 : <T extends number>(arg: T) => any
+>arg : T
+
+  return { ...arg };
+>{ ...arg } : any
+>arg : T
+}
+
+function f2<T extends string[]>(arg: T) {
+>f2 : <T extends string[]>(arg: T) => T
+>arg : T
+
+  return { ...arg }
+>{ ...arg } : T
+>arg : T
+}
+
+function f3<T extends number | string[]>(arg: T) {
+>f3 : <T extends number | string[]>(arg: T) => any
+>arg : T
+
+  return { ...arg }
+>{ ...arg } : any
+>arg : T
+}
+
+function f4<T extends number | { [key: string]: any }>(arg: T) {
+>f4 : <T extends number | { [key: string]: any; }>(arg: T) => any
+>key : string
+>arg : T
+
+  return { ...arg }
+>{ ...arg } : any
+>arg : T
+}
+
+function f5<T extends string[] | { [key: string]: any }>(arg: T) {
+>f5 : <T extends string[] | { [key: string]: any; }>(arg: T) => T
+>key : string
+>arg : T
+
+  return { ...arg }
+>{ ...arg } : T
+>arg : T
+}
+
+function f6<T>(arg: T) {
+>f6 : <T>(arg: T) => T
+>arg : T
+
+  return { ...arg }
+>{ ...arg } : T
+>arg : T
+}
+
+

tests/cases/compiler/spreadInvalidArgumentType.ts

@@ -30,7 +30,7 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
     var o1 = { ...p1 };  // OK, generic type paramterre
     var o2 = { ...p2 };  // OK
     var o3 = { ...t };   // OK, generic type paramter
-    var o4 = { ...i };   // OK, index access
+    var o4 = { ...i };   // Error, index access
     var o5 = { ...k };   // Error, index
     var o6 = { ...mapped_generic }; // OK, generic mapped object type
     var o7 = { ...mapped };  // OK, non-generic mapped type

tests/cases/conformance/types/spread/spreadTypeVariable.ts

@@ -0,0 +1,24 @@
+function f1<T extends number>(arg: T) {
+  return { ...arg };
+}
+
+function f2<T extends string[]>(arg: T) {
+  return { ...arg }
+}
+
+function f3<T extends number | string[]>(arg: T) {
+  return { ...arg }
+}
+
+function f4<T extends number | { [key: string]: any }>(arg: T) {
+  return { ...arg }
+}
+
+function f5<T extends string[] | { [key: string]: any }>(arg: T) {
+  return { ...arg }
+}
+
+function f6<T>(arg: T) {
+  return { ...arg }
+}
+