Spread type:new assignability+simplification tests

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

@@ -1,13 +1,12 @@
 function f<T, U, V>(t: T, u: U, v: V): void {
     let o: { ...T, ...U, ...V };
-    let uu: { ...U, ...U};
-    let u: { ...U };
-    let u0: U;
-    uu = u; // ok, multiple spreads are equivalent to a single one
-    u = uu; // ok, multiple spreads are equivalent to a single one
-    u0 = u; // error, might be missing a ton of stuff
-    u = u0; // ok, type has at least all the properties of the spread
+    let uus: { ...U, ...U};
+    let us: { ...U };
     const same: { ...T, ...U, ...V } = o; // ok
+    uus = us; // ok, multiple spreads are equivalent to a single one
+    us = uus; // ok, multiple spreads are equivalent to a single one
+    us = u;   // ok, type has at least all the properties of the spread
+    u = us;   // error, might be missing a ton of stuff
     const reversed: { ...V, ...U, ...T } = o; // error, reversed
     const reversed2: { ...U, ...T, ...V } = o; // error, U and T are still reversed
     const missingT: { ...U, ...V } = o; // error, missing T

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

@@ -8,10 +8,8 @@ class PrivateOptionalX {
 class PublicX {
     public x: number;
 }
-let privateOptionalx: PrivateOptionalX;
-let publicx: PublicX;
-let o3 = { ...publicx, ...privateOptionalx };
-let sn: string | number = o3.x; // error, x is private
+let o3: { ...PublicX, ...PrivateOptionalX };
+let sn: number = o3.x; // error, x is private
 let optionalString: { sn?: string };
 let optionalNumber: { sn?: number };
 let allOptional: { sn: string | number } = { ...optionalString, ...optionalNumber };
@@ -46,6 +44,7 @@ let callableConstructableSpread: { ...PublicX, (n: number): number, new (p: numb
 callableConstructableSpread(12); // error, no call signature
 new callableConstructableSpread(12); // error, no construct signature
 
+let publicx: PublicX;
 let callableSpread = { ...publicx, ...(n => n + 1) }; // error, can't spread functions
 
 // { ...U } is not assignable to U

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

@@ -3,7 +3,7 @@ interface B1 { b: number };
 function override<U>(initial: U, override: U): { ...U, ...U } {
     return { ...initial, ...override };
 }
-function update<U>(this: { u: U }, override: U): void {
+function update<U>(this: { u: { ...U } }, override: U): void {
     this.u = { ...this.u, ...override };
 }
 function mixin<T, U>(one: T, two: U): { ...T, ...U } {

tests/cases/fourslash/findAllRefsForObjectSpread.ts

@@ -1,6 +1,6 @@
 /// <reference path='fourslash.ts'/>
 
-////interface A1 { [|a|]: number };
+////interface A1 { [|a|]: string };
 ////interface A2 { [|a|]?: number };
 ////let a12: { ...A1, ...A2 };
 ////a12.[|a|];