Handel null and undefined in object spread and rest

src/compiler/checker.ts

@@ -3055,7 +3055,10 @@ namespace ts {
 
         function getRestType(source: Type, properties: PropertyName[], symbol: Symbol): Type {
             if (source.flags & TypeFlags.Union) {
-                return getUnionType(map((<UnionType>source).types, t => getRestType(t, properties, symbol)));
+                const types = filter((<UnionType>source).types, t => !(t.flags & TypeFlags.Nullable));
+                if (types.length) {
+                    return getUnionType(map(types, t => getRestType(t, properties, symbol)));
+                }
             }
 
             const members = createMap<Symbol>();
@@ -6111,11 +6114,29 @@ namespace ts {
             }
 
             if (left.flags & TypeFlags.Union) {
-                return getUnionType(map((<UnionType>left).types, t => getSpreadType(t, right, isFromObjectLiteral)));
+                const types = filter((<UnionType>left).types, t => !(t.flags & TypeFlags.Nullable));
+                if (types.length) {
+                    return getUnionType(map(types, t => getSpreadType(t, right, isFromObjectLiteral)));
+                }
+                else {
+                    left = emptyObjectType
+                }
+            }
+            else if (left.flags & TypeFlags.Nullable) {
+                left = emptyObjectType;
             }
 
             if (right.flags & TypeFlags.Union) {
-                return getUnionType(map((<UnionType>right).types, t => getSpreadType(left, t, isFromObjectLiteral)));
+                const types = filter((<UnionType>right).types, t => !(t.flags & TypeFlags.Nullable));
+                if (types.length) {
+                    return getUnionType(map(types, t => getSpreadType(left, t, isFromObjectLiteral)));
+                }
+                else {
+                    right = emptyObjectType
+                }
+            }
+            else if (right.flags & TypeFlags.Nullable) {
+                right = emptyObjectType;
             }
 
             const members = createMap<Symbol>();
@@ -11528,7 +11549,7 @@ namespace ts {
        }
 
         function isValidSpreadType(type: Type): boolean {
-            if (type.flags & TypeFlags.Any) {
+            if (type.flags & (TypeFlags.Any | TypeFlags.Null | TypeFlags.Undefined)) {
                 return true;
             }
             if (type.flags & TypeFlags.Object) {
@@ -11540,6 +11561,7 @@ namespace ts {
                         return false;
                     }
                 }
+                return true;
             }
             return false;
         }

tests/baselines/reference/objectSpreadNegative.errors.txt

@@ -7,8 +7,6 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(25,1): error TS2322
   Property 's' is missing in type '{ b: boolean; }'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(28,36): error TS2300: Duplicate identifier 'b'.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(28,53): error TS2300: Duplicate identifier 'b'.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(32,20): error TS2698: Spread types may only be created from object types.
-tests/cases/conformance/types/spread/objectSpreadNegative.ts(33,24): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(34,19): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(35,19): error TS2698: Spread types may only be created from object types.
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(37,20): error TS2698: Spread types may only be created from object types.
@@ -20,7 +18,7 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(58,14): error TS269
 tests/cases/conformance/types/spread/objectSpreadNegative.ts(61,14): error TS2698: Spread types may only be created from object types.
 
 
-==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (17 errors) ====
+==== tests/cases/conformance/types/spread/objectSpreadNegative.ts (15 errors) ====
     let o = { a: 1, b: 'no' }
     
     /// private propagates
@@ -68,11 +66,7 @@ tests/cases/conformance/types/spread/objectSpreadNegative.ts(61,14): error TS269
     
     // null, undefined and primitives are not allowed
     let spreadNull = { ...null };
-                       ~~~~~~~
-!!! error TS2698: Spread types may only be created from object types.
     let spreadUndefind = { ...undefined };
-                           ~~~~~~~~~~~~
-!!! error TS2698: Spread types may only be created from object types.
     let spreadNum = { ...12 };
                       ~~~~~
 !!! error TS2698: Spread types may only be created from object types.

tests/baselines/reference/restInvalidArgumentType.errors.txt

@@ -9,14 +9,12 @@ tests/cases/compiler/restInvalidArgumentType.ts(44,13): error TS2700: Rest types
 tests/cases/compiler/restInvalidArgumentType.ts(45,13): error TS2700: Rest types may only be created from object types.
 tests/cases/compiler/restInvalidArgumentType.ts(47,13): error TS2700: Rest types may only be created from object types.
 tests/cases/compiler/restInvalidArgumentType.ts(48,13): error TS2700: Rest types may only be created from object types.
-tests/cases/compiler/restInvalidArgumentType.ts(50,13): error TS2700: Rest types may only be created from object types.
-tests/cases/compiler/restInvalidArgumentType.ts(51,13): error TS2700: Rest types may only be created from object types.
 tests/cases/compiler/restInvalidArgumentType.ts(55,13): error TS2700: Rest types may only be created from object types.
 tests/cases/compiler/restInvalidArgumentType.ts(56,13): error TS2700: Rest types may only be created from object types.
 tests/cases/compiler/restInvalidArgumentType.ts(58,13): error TS2700: Rest types may only be created from object types.
 
 
-==== tests/cases/compiler/restInvalidArgumentType.ts (16 errors) ====
+==== tests/cases/compiler/restInvalidArgumentType.ts (14 errors) ====
     enum E { v1, v2 };
     
     function f<T extends { b: string }>(p1: T, p2: T[]) {
@@ -88,12 +86,8 @@ tests/cases/compiler/restInvalidArgumentType.ts(58,13): error TS2700: Rest types
                 ~~~
 !!! error TS2700: Rest types may only be created from object types.
     
-        var {...r14} = u;  // Error
-                ~~~
-!!! error TS2700: Rest types may only be created from object types.
-        var {...r15} = n;  // Error
-                ~~~
-!!! error TS2700: Rest types may only be created from object types.
+        var {...r14} = u;  // OK
+        var {...r15} = n;  // OK
     
         var {...r16} = a;  // OK
     

tests/baselines/reference/restInvalidArgumentType.js

@@ -48,8 +48,8 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
     var {...r12} = num;  // Error
     var {...r13} = str;  // Error
 
-    var {...r14} = u;  // Error
-    var {...r15} = n;  // Error
+    var {...r14} = u;  // OK
+    var {...r15} = n;  // OK
 
     var {...r16} = a;  // OK
 
@@ -106,8 +106,8 @@ function f(p1, p2) {
     var r11 = __rest(intersection_premitive, []); // Error, intersection with generic type parameter
     var r12 = __rest(num, []); // Error
     var r13 = __rest(str, []); // Error
-    var r14 = __rest(u, []); // Error
-    var r15 = __rest(n, []); // Error
+    var r14 = __rest(u, []); // OK
+    var r15 = __rest(n, []); // OK
     var r16 = __rest(a, []); // OK
     var r17 = __rest(literal_string, []); // Error
     var r18 = __rest(literal_number, []); // Error

tests/baselines/reference/restUnion.js

@@ -0,0 +1,36 @@
+//// [restUnion.ts]
+var union: { a: number, c: boolean } | { a: string, b: string };
+
+var rest1: { c: boolean } | { b: string };
+var {a, ...rest1 } = union;
+
+
+var undefinedUnion: { n: number } | undefined;
+var rest2: {};
+var {n, ...rest2 } = undefinedUnion;
+
+
+var nullUnion: { n: number } | null;
+var rest3: {};
+var {n, ...rest3 } = nullUnion;
+
+
+//// [restUnion.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
+        t[p] = s[p];
+    if (typeof Object.getOwnPropertySymbols === "function")
+        for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)
+            t[p[i]] = s[p[i]];
+    return t;
+};
+var union;
+var rest1;
+var a = union.a, rest1 = __rest(union, ["a"]);
+var undefinedUnion;
+var rest2;
+var n = undefinedUnion.n, rest2 = __rest(undefinedUnion, ["n"]);
+var nullUnion;
+var rest3;
+var n = nullUnion.n, rest3 = __rest(nullUnion, ["n"]);

tests/baselines/reference/restUnion.symbols

@@ -0,0 +1,44 @@
+=== tests/cases/compiler/restUnion.ts ===
+var union: { a: number, c: boolean } | { a: string, b: string };
+>union : Symbol(union, Decl(restUnion.ts, 0, 3))
+>a : Symbol(a, Decl(restUnion.ts, 0, 12))
+>c : Symbol(c, Decl(restUnion.ts, 0, 23))
+>a : Symbol(a, Decl(restUnion.ts, 0, 40))
+>b : Symbol(b, Decl(restUnion.ts, 0, 51))
+
+var rest1: { c: boolean } | { b: string };
+>rest1 : Symbol(rest1, Decl(restUnion.ts, 2, 3), Decl(restUnion.ts, 3, 7))
+>c : Symbol(c, Decl(restUnion.ts, 2, 12))
+>b : Symbol(b, Decl(restUnion.ts, 2, 29))
+
+var {a, ...rest1 } = union;
+>a : Symbol(a, Decl(restUnion.ts, 3, 5))
+>rest1 : Symbol(rest1, Decl(restUnion.ts, 2, 3), Decl(restUnion.ts, 3, 7))
+>union : Symbol(union, Decl(restUnion.ts, 0, 3))
+
+
+var undefinedUnion: { n: number } | undefined;
+>undefinedUnion : Symbol(undefinedUnion, Decl(restUnion.ts, 6, 3))
+>n : Symbol(n, Decl(restUnion.ts, 6, 21))
+
+var rest2: {};
+>rest2 : Symbol(rest2, Decl(restUnion.ts, 7, 3), Decl(restUnion.ts, 8, 7))
+
+var {n, ...rest2 } = undefinedUnion;
+>n : Symbol(n, Decl(restUnion.ts, 8, 5), Decl(restUnion.ts, 13, 5))
+>rest2 : Symbol(rest2, Decl(restUnion.ts, 7, 3), Decl(restUnion.ts, 8, 7))
+>undefinedUnion : Symbol(undefinedUnion, Decl(restUnion.ts, 6, 3))
+
+
+var nullUnion: { n: number } | null;
+>nullUnion : Symbol(nullUnion, Decl(restUnion.ts, 11, 3))
+>n : Symbol(n, Decl(restUnion.ts, 11, 16))
+
+var rest3: {};
+>rest3 : Symbol(rest3, Decl(restUnion.ts, 12, 3), Decl(restUnion.ts, 13, 7))
+
+var {n, ...rest3 } = nullUnion;
+>n : Symbol(n, Decl(restUnion.ts, 8, 5), Decl(restUnion.ts, 13, 5))
+>rest3 : Symbol(rest3, Decl(restUnion.ts, 12, 3), Decl(restUnion.ts, 13, 7))
+>nullUnion : Symbol(nullUnion, Decl(restUnion.ts, 11, 3))
+

tests/baselines/reference/restUnion.types

@@ -0,0 +1,45 @@
+=== tests/cases/compiler/restUnion.ts ===
+var union: { a: number, c: boolean } | { a: string, b: string };
+>union : { a: number; c: boolean; } | { a: string; b: string; }
+>a : number
+>c : boolean
+>a : string
+>b : string
+
+var rest1: { c: boolean } | { b: string };
+>rest1 : { c: boolean; } | { b: string; }
+>c : boolean
+>b : string
+
+var {a, ...rest1 } = union;
+>a : string | number
+>rest1 : { c: boolean; } | { b: string; }
+>union : { a: number; c: boolean; } | { a: string; b: string; }
+
+
+var undefinedUnion: { n: number } | undefined;
+>undefinedUnion : { n: number; }
+>n : number
+
+var rest2: {};
+>rest2 : {}
+
+var {n, ...rest2 } = undefinedUnion;
+>n : number
+>rest2 : {}
+>undefinedUnion : { n: number; }
+
+
+var nullUnion: { n: number } | null;
+>nullUnion : { n: number; }
+>n : number
+>null : null
+
+var rest3: {};
+>rest3 : {}
+
+var {n, ...rest3 } = nullUnion;
+>n : number
+>rest3 : {}
+>nullUnion : { n: number; }
+

tests/baselines/reference/restUnion2.js

@@ -0,0 +1,38 @@
+//// [restUnion2.ts]
+
+declare const undefinedUnion: { n: number } | undefined;
+var rest2: { n: number };
+var {...rest2 } = undefinedUnion;
+
+
+declare const nullUnion: { n: number } | null;
+var rest3: { n: number };
+var {...rest3 } = nullUnion;
+
+
+declare const nullAndUndefinedUnion: null | undefined;
+var rest4: { };
+var {...rest4 } = nullAndUndefinedUnion;
+
+declare const unionWithIntersection: ({ n: number } & { s: string }) & undefined | null;
+var rest5: { n: number, s: string };
+var {...rest5 } = unionWithIntersection;
+
+//// [restUnion2.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
+        t[p] = s[p];
+    if (typeof Object.getOwnPropertySymbols === "function")
+        for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0)
+            t[p[i]] = s[p[i]];
+    return t;
+};
+var rest2;
+var rest2 = __rest(undefinedUnion, []);
+var rest3;
+var rest3 = __rest(nullUnion, []);
+var rest4;
+var rest4 = __rest(nullAndUndefinedUnion, []);
+var rest5;
+var rest5 = __rest(unionWithIntersection, []);

tests/baselines/reference/restUnion2.symbols

@@ -0,0 +1,52 @@
+=== tests/cases/compiler/restUnion2.ts ===
+
+declare const undefinedUnion: { n: number } | undefined;
+>undefinedUnion : Symbol(undefinedUnion, Decl(restUnion2.ts, 1, 13))
+>n : Symbol(n, Decl(restUnion2.ts, 1, 31))
+
+var rest2: { n: number };
+>rest2 : Symbol(rest2, Decl(restUnion2.ts, 2, 3), Decl(restUnion2.ts, 3, 5))
+>n : Symbol(n, Decl(restUnion2.ts, 2, 12))
+
+var {...rest2 } = undefinedUnion;
+>rest2 : Symbol(rest2, Decl(restUnion2.ts, 2, 3), Decl(restUnion2.ts, 3, 5))
+>undefinedUnion : Symbol(undefinedUnion, Decl(restUnion2.ts, 1, 13))
+
+
+declare const nullUnion: { n: number } | null;
+>nullUnion : Symbol(nullUnion, Decl(restUnion2.ts, 6, 13))
+>n : Symbol(n, Decl(restUnion2.ts, 6, 26))
+
+var rest3: { n: number };
+>rest3 : Symbol(rest3, Decl(restUnion2.ts, 7, 3), Decl(restUnion2.ts, 8, 5))
+>n : Symbol(n, Decl(restUnion2.ts, 7, 12))
+
+var {...rest3 } = nullUnion;
+>rest3 : Symbol(rest3, Decl(restUnion2.ts, 7, 3), Decl(restUnion2.ts, 8, 5))
+>nullUnion : Symbol(nullUnion, Decl(restUnion2.ts, 6, 13))
+
+
+declare const nullAndUndefinedUnion: null | undefined;
+>nullAndUndefinedUnion : Symbol(nullAndUndefinedUnion, Decl(restUnion2.ts, 11, 13))
+
+var rest4: { };
+>rest4 : Symbol(rest4, Decl(restUnion2.ts, 12, 3), Decl(restUnion2.ts, 13, 5))
+
+var {...rest4 } = nullAndUndefinedUnion;
+>rest4 : Symbol(rest4, Decl(restUnion2.ts, 12, 3), Decl(restUnion2.ts, 13, 5))
+>nullAndUndefinedUnion : Symbol(nullAndUndefinedUnion, Decl(restUnion2.ts, 11, 13))
+
+declare const unionWithIntersection: ({ n: number } & { s: string }) & undefined | null;
+>unionWithIntersection : Symbol(unionWithIntersection, Decl(restUnion2.ts, 15, 13))
+>n : Symbol(n, Decl(restUnion2.ts, 15, 39))
+>s : Symbol(s, Decl(restUnion2.ts, 15, 55))
+
+var rest5: { n: number, s: string };
+>rest5 : Symbol(rest5, Decl(restUnion2.ts, 16, 3), Decl(restUnion2.ts, 17, 5))
+>n : Symbol(n, Decl(restUnion2.ts, 16, 12))
+>s : Symbol(s, Decl(restUnion2.ts, 16, 23))
+
+var {...rest5 } = unionWithIntersection;
+>rest5 : Symbol(rest5, Decl(restUnion2.ts, 16, 3), Decl(restUnion2.ts, 17, 5))
+>unionWithIntersection : Symbol(unionWithIntersection, Decl(restUnion2.ts, 15, 13))
+

tests/baselines/reference/restUnion2.types

@@ -0,0 +1,55 @@
+=== tests/cases/compiler/restUnion2.ts ===
+
+declare const undefinedUnion: { n: number } | undefined;
+>undefinedUnion : { n: number; } | undefined
+>n : number
+
+var rest2: { n: number };
+>rest2 : { n: number; }
+>n : number
+
+var {...rest2 } = undefinedUnion;
+>rest2 : { n: number; }
+>undefinedUnion : { n: number; } | undefined
+
+
+declare const nullUnion: { n: number } | null;
+>nullUnion : { n: number; } | null
+>n : number
+>null : null
+
+var rest3: { n: number };
+>rest3 : { n: number; }
+>n : number
+
+var {...rest3 } = nullUnion;
+>rest3 : { n: number; }
+>nullUnion : { n: number; } | null
+
+
+declare const nullAndUndefinedUnion: null | undefined;
+>nullAndUndefinedUnion : null | undefined
+>null : null
+
+var rest4: { };
+>rest4 : {}
+
+var {...rest4 } = nullAndUndefinedUnion;
+>rest4 : {}
+>nullAndUndefinedUnion : null | undefined
+
+declare const unionWithIntersection: ({ n: number } & { s: string }) & undefined | null;
+>unionWithIntersection : ({ n: number; } & { s: string; } & undefined) | null
+>n : number
+>s : string
+>null : null
+
+var rest5: { n: number, s: string };
+>rest5 : { n: number; s: string; }
+>n : number
+>s : string
+
+var {...rest5 } = unionWithIntersection;
+>rest5 : { n: number; s: string; }
+>unionWithIntersection : ({ n: number; } & { s: string; } & undefined) | null
+

tests/baselines/reference/spreadInvalidArgumentType.errors.txt

@@ -9,14 +9,12 @@ tests/cases/compiler/spreadInvalidArgumentType.ts(44,17): error TS2698: Spread t
 tests/cases/compiler/spreadInvalidArgumentType.ts(45,17): error TS2698: Spread types may only be created from object types.
 tests/cases/compiler/spreadInvalidArgumentType.ts(47,17): error TS2698: Spread types may only be created from object types.
 tests/cases/compiler/spreadInvalidArgumentType.ts(48,17): error TS2698: Spread types may only be created from object types.
-tests/cases/compiler/spreadInvalidArgumentType.ts(50,17): error TS2698: Spread types may only be created from object types.
-tests/cases/compiler/spreadInvalidArgumentType.ts(51,17): error TS2698: Spread types may only be created from object types.
 tests/cases/compiler/spreadInvalidArgumentType.ts(55,17): error TS2698: Spread types may only be created from object types.
 tests/cases/compiler/spreadInvalidArgumentType.ts(56,17): error TS2698: Spread types may only be created from object types.
 tests/cases/compiler/spreadInvalidArgumentType.ts(58,17): error TS2698: Spread types may only be created from object types.
 
 
-==== tests/cases/compiler/spreadInvalidArgumentType.ts (16 errors) ====
+==== tests/cases/compiler/spreadInvalidArgumentType.ts (14 errors) ====
     enum E { v1, v2 };
     
     function f<T extends { b: string }>(p1: T, p2: T[]) {
@@ -88,12 +86,8 @@ tests/cases/compiler/spreadInvalidArgumentType.ts(58,17): error TS2698: Spread t
                     ~~~~~~
 !!! error TS2698: Spread types may only be created from object types.
     
-        var o14 = { ...u };  // Error
-                    ~~~~
-!!! error TS2698: Spread types may only be created from object types.
-        var o15 = { ...n };  // Error
-                    ~~~~
-!!! error TS2698: Spread types may only be created from object types.
+        var o14 = { ...u };  // OK
+        var o15 = { ...n };  // OK
     
         var o16 = { ...a };  // OK
     

tests/baselines/reference/spreadInvalidArgumentType.js

@@ -48,8 +48,8 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
     var o12 = { ...num };  // Error
     var o13 = { ...str };  // Error
 
-    var o14 = { ...u };  // Error
-    var o15 = { ...n };  // Error
+    var o14 = { ...u };  // OK
+    var o15 = { ...n };  // OK
 
     var o16 = { ...a };  // OK
 
@@ -105,8 +105,8 @@ function f(p1, p2) {
     var o11 = __assign({}, intersection_premitive); // Error, intersection with generic type parameter
     var o12 = __assign({}, num); // Error
     var o13 = __assign({}, str); // Error
-    var o14 = __assign({}, u); // Error
-    var o15 = __assign({}, n); // Error
+    var o14 = __assign({}, u); // OK
+    var o15 = __assign({}, n); // OK
     var o16 = __assign({}, a); // OK
     var o17 = __assign({}, literal_string); // Error
     var o18 = __assign({}, literal_number); // Error

tests/baselines/reference/spreadUnion2.js

@@ -0,0 +1,49 @@
+//// [spreadUnion2.ts]
+
+declare const undefinedUnion: { a: number } | undefined;
+declare const nullUnion: { b: number } | null;
+declare const nullAndUndefinedUnion: null | undefined;
+
+var o1: { a: number };
+var o1 = { ...undefinedUnion };
+
+var o2: { b: number };
+var o2 = { ...nullUnion };
+
+var o3: { a: number, b: number };
+var o3 = { ...undefinedUnion, ...nullUnion };
+var o3 = { ...nullUnion, ...undefinedUnion };
+
+var o4: { a: number };
+var o4 = { ...undefinedUnion, ...undefinedUnion };
+
+var o5: { b: number };
+var o5 = { ...nullUnion, ...nullUnion };
+
+var o6: { };
+var o6 = { ...nullAndUndefinedUnion, ...nullAndUndefinedUnion };
+var o6 = { ...nullAndUndefinedUnion };
+
+//// [spreadUnion2.js]
+var __assign = (this && this.__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;
+};
+var o1;
+var o1 = __assign({}, undefinedUnion);
+var o2;
+var o2 = __assign({}, nullUnion);
+var o3;
+var o3 = __assign({}, undefinedUnion, nullUnion);
+var o3 = __assign({}, nullUnion, undefinedUnion);
+var o4;
+var o4 = __assign({}, undefinedUnion, undefinedUnion);
+var o5;
+var o5 = __assign({}, nullUnion, nullUnion);
+var o6;
+var o6 = __assign({}, nullAndUndefinedUnion, nullAndUndefinedUnion);
+var o6 = __assign({}, nullAndUndefinedUnion);

tests/baselines/reference/spreadUnion2.symbols

@@ -0,0 +1,74 @@
+=== tests/cases/compiler/spreadUnion2.ts ===
+
+declare const undefinedUnion: { a: number } | undefined;
+>undefinedUnion : Symbol(undefinedUnion, Decl(spreadUnion2.ts, 1, 13))
+>a : Symbol(a, Decl(spreadUnion2.ts, 1, 31))
+
+declare const nullUnion: { b: number } | null;
+>nullUnion : Symbol(nullUnion, Decl(spreadUnion2.ts, 2, 13))
+>b : Symbol(b, Decl(spreadUnion2.ts, 2, 26))
+
+declare const nullAndUndefinedUnion: null | undefined;
+>nullAndUndefinedUnion : Symbol(nullAndUndefinedUnion, Decl(spreadUnion2.ts, 3, 13))
+
+var o1: { a: number };
+>o1 : Symbol(o1, Decl(spreadUnion2.ts, 5, 3), Decl(spreadUnion2.ts, 6, 3))
+>a : Symbol(a, Decl(spreadUnion2.ts, 5, 9))
+
+var o1 = { ...undefinedUnion };
+>o1 : Symbol(o1, Decl(spreadUnion2.ts, 5, 3), Decl(spreadUnion2.ts, 6, 3))
+>undefinedUnion : Symbol(undefinedUnion, Decl(spreadUnion2.ts, 1, 13))
+
+var o2: { b: number };
+>o2 : Symbol(o2, Decl(spreadUnion2.ts, 8, 3), Decl(spreadUnion2.ts, 9, 3))
+>b : Symbol(b, Decl(spreadUnion2.ts, 8, 9))
+
+var o2 = { ...nullUnion };
+>o2 : Symbol(o2, Decl(spreadUnion2.ts, 8, 3), Decl(spreadUnion2.ts, 9, 3))
+>nullUnion : Symbol(nullUnion, Decl(spreadUnion2.ts, 2, 13))
+
+var o3: { a: number, b: number };
+>o3 : Symbol(o3, Decl(spreadUnion2.ts, 11, 3), Decl(spreadUnion2.ts, 12, 3), Decl(spreadUnion2.ts, 13, 3))
+>a : Symbol(a, Decl(spreadUnion2.ts, 11, 9))
+>b : Symbol(b, Decl(spreadUnion2.ts, 11, 20))
+
+var o3 = { ...undefinedUnion, ...nullUnion };
+>o3 : Symbol(o3, Decl(spreadUnion2.ts, 11, 3), Decl(spreadUnion2.ts, 12, 3), Decl(spreadUnion2.ts, 13, 3))
+>undefinedUnion : Symbol(undefinedUnion, Decl(spreadUnion2.ts, 1, 13))
+>nullUnion : Symbol(nullUnion, Decl(spreadUnion2.ts, 2, 13))
+
+var o3 = { ...nullUnion, ...undefinedUnion };
+>o3 : Symbol(o3, Decl(spreadUnion2.ts, 11, 3), Decl(spreadUnion2.ts, 12, 3), Decl(spreadUnion2.ts, 13, 3))
+>nullUnion : Symbol(nullUnion, Decl(spreadUnion2.ts, 2, 13))
+>undefinedUnion : Symbol(undefinedUnion, Decl(spreadUnion2.ts, 1, 13))
+
+var o4: { a: number };
+>o4 : Symbol(o4, Decl(spreadUnion2.ts, 15, 3), Decl(spreadUnion2.ts, 16, 3))
+>a : Symbol(a, Decl(spreadUnion2.ts, 15, 9))
+
+var o4 = { ...undefinedUnion, ...undefinedUnion };
+>o4 : Symbol(o4, Decl(spreadUnion2.ts, 15, 3), Decl(spreadUnion2.ts, 16, 3))
+>undefinedUnion : Symbol(undefinedUnion, Decl(spreadUnion2.ts, 1, 13))
+>undefinedUnion : Symbol(undefinedUnion, Decl(spreadUnion2.ts, 1, 13))
+
+var o5: { b: number };
+>o5 : Symbol(o5, Decl(spreadUnion2.ts, 18, 3), Decl(spreadUnion2.ts, 19, 3))
+>b : Symbol(b, Decl(spreadUnion2.ts, 18, 9))
+
+var o5 = { ...nullUnion, ...nullUnion };
+>o5 : Symbol(o5, Decl(spreadUnion2.ts, 18, 3), Decl(spreadUnion2.ts, 19, 3))
+>nullUnion : Symbol(nullUnion, Decl(spreadUnion2.ts, 2, 13))
+>nullUnion : Symbol(nullUnion, Decl(spreadUnion2.ts, 2, 13))
+
+var o6: { };
+>o6 : Symbol(o6, Decl(spreadUnion2.ts, 21, 3), Decl(spreadUnion2.ts, 22, 3), Decl(spreadUnion2.ts, 23, 3))
+
+var o6 = { ...nullAndUndefinedUnion, ...nullAndUndefinedUnion };
+>o6 : Symbol(o6, Decl(spreadUnion2.ts, 21, 3), Decl(spreadUnion2.ts, 22, 3), Decl(spreadUnion2.ts, 23, 3))
+>nullAndUndefinedUnion : Symbol(nullAndUndefinedUnion, Decl(spreadUnion2.ts, 3, 13))
+>nullAndUndefinedUnion : Symbol(nullAndUndefinedUnion, Decl(spreadUnion2.ts, 3, 13))
+
+var o6 = { ...nullAndUndefinedUnion };
+>o6 : Symbol(o6, Decl(spreadUnion2.ts, 21, 3), Decl(spreadUnion2.ts, 22, 3), Decl(spreadUnion2.ts, 23, 3))
+>nullAndUndefinedUnion : Symbol(nullAndUndefinedUnion, Decl(spreadUnion2.ts, 3, 13))
+

tests/baselines/reference/spreadUnion2.types

@@ -0,0 +1,84 @@
+=== tests/cases/compiler/spreadUnion2.ts ===
+
+declare const undefinedUnion: { a: number } | undefined;
+>undefinedUnion : { a: number; } | undefined
+>a : number
+
+declare const nullUnion: { b: number } | null;
+>nullUnion : { b: number; } | null
+>b : number
+>null : null
+
+declare const nullAndUndefinedUnion: null | undefined;
+>nullAndUndefinedUnion : null | undefined
+>null : null
+
+var o1: { a: number };
+>o1 : { a: number; }
+>a : number
+
+var o1 = { ...undefinedUnion };
+>o1 : { a: number; }
+>{ ...undefinedUnion } : { a: number; }
+>undefinedUnion : { a: number; } | undefined
+
+var o2: { b: number };
+>o2 : { b: number; }
+>b : number
+
+var o2 = { ...nullUnion };
+>o2 : { b: number; }
+>{ ...nullUnion } : { b: number; }
+>nullUnion : { b: number; } | null
+
+var o3: { a: number, b: number };
+>o3 : { a: number; b: number; }
+>a : number
+>b : number
+
+var o3 = { ...undefinedUnion, ...nullUnion };
+>o3 : { a: number; b: number; }
+>{ ...undefinedUnion, ...nullUnion } : { b: number; a: number; }
+>undefinedUnion : { a: number; } | undefined
+>nullUnion : { b: number; } | null
+
+var o3 = { ...nullUnion, ...undefinedUnion };
+>o3 : { a: number; b: number; }
+>{ ...nullUnion, ...undefinedUnion } : { a: number; b: number; }
+>nullUnion : { b: number; } | null
+>undefinedUnion : { a: number; } | undefined
+
+var o4: { a: number };
+>o4 : { a: number; }
+>a : number
+
+var o4 = { ...undefinedUnion, ...undefinedUnion };
+>o4 : { a: number; }
+>{ ...undefinedUnion, ...undefinedUnion } : { a: number; }
+>undefinedUnion : { a: number; } | undefined
+>undefinedUnion : { a: number; } | undefined
+
+var o5: { b: number };
+>o5 : { b: number; }
+>b : number
+
+var o5 = { ...nullUnion, ...nullUnion };
+>o5 : { b: number; }
+>{ ...nullUnion, ...nullUnion } : { b: number; }
+>nullUnion : { b: number; } | null
+>nullUnion : { b: number; } | null
+
+var o6: { };
+>o6 : {}
+
+var o6 = { ...nullAndUndefinedUnion, ...nullAndUndefinedUnion };
+>o6 : {}
+>{ ...nullAndUndefinedUnion, ...nullAndUndefinedUnion } : {}
+>nullAndUndefinedUnion : null | undefined
+>nullAndUndefinedUnion : null | undefined
+
+var o6 = { ...nullAndUndefinedUnion };
+>o6 : {}
+>{ ...nullAndUndefinedUnion } : {}
+>nullAndUndefinedUnion : null | undefined
+

tests/cases/compiler/restInvalidArgumentType.ts

@@ -47,8 +47,8 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
     var {...r12} = num;  // Error
     var {...r13} = str;  // Error
 
-    var {...r14} = u;  // Error
-    var {...r15} = n;  // Error
+    var {...r14} = u;  // OK
+    var {...r15} = n;  // OK
 
     var {...r16} = a;  // OK
 

tests/cases/compiler/restUnion.ts

@@ -0,0 +1,14 @@
+var union: { a: number, c: boolean } | { a: string, b: string };
+
+var rest1: { c: boolean } | { b: string };
+var {a, ...rest1 } = union;
+
+
+var undefinedUnion: { n: number } | undefined;
+var rest2: {};
+var {n, ...rest2 } = undefinedUnion;
+
+
+var nullUnion: { n: number } | null;
+var rest3: {};
+var {n, ...rest3 } = nullUnion;

tests/cases/compiler/restUnion2.ts

@@ -0,0 +1,19 @@
+// @strictNullChecks: true
+
+declare const undefinedUnion: { n: number } | undefined;
+var rest2: { n: number };
+var {...rest2 } = undefinedUnion;
+
+
+declare const nullUnion: { n: number } | null;
+var rest3: { n: number };
+var {...rest3 } = nullUnion;
+
+
+declare const nullAndUndefinedUnion: null | undefined;
+var rest4: { };
+var {...rest4 } = nullAndUndefinedUnion;
+
+declare const unionWithIntersection: ({ n: number } & { s: string }) & undefined | null;
+var rest5: { n: number, s: string };
+var {...rest5 } = unionWithIntersection;

tests/cases/compiler/spreadInvalidArgumentType.ts

@@ -47,8 +47,8 @@ function f<T extends { b: string }>(p1: T, p2: T[]) {
     var o12 = { ...num };  // Error
     var o13 = { ...str };  // Error
 
-    var o14 = { ...u };  // Error
-    var o15 = { ...n };  // Error
+    var o14 = { ...u };  // OK
+    var o15 = { ...n };  // OK
 
     var o16 = { ...a };  // OK
 

tests/cases/compiler/spreadUnion2.ts

@@ -0,0 +1,25 @@
+// @strictNullChecks: true
+
+declare const undefinedUnion: { a: number } | undefined;
+declare const nullUnion: { b: number } | null;
+declare const nullAndUndefinedUnion: null | undefined;
+
+var o1: { a: number };
+var o1 = { ...undefinedUnion };
+
+var o2: { b: number };
+var o2 = { ...nullUnion };
+
+var o3: { a: number, b: number };
+var o3 = { ...undefinedUnion, ...nullUnion };
+var o3 = { ...nullUnion, ...undefinedUnion };
+
+var o4: { a: number };
+var o4 = { ...undefinedUnion, ...undefinedUnion };
+
+var o5: { b: number };
+var o5 = { ...nullUnion, ...nullUnion };
+
+var o6: { };
+var o6 = { ...nullAndUndefinedUnion, ...nullAndUndefinedUnion };
+var o6 = { ...nullAndUndefinedUnion };