Fix exceptions on empty tuple errors (microsoft#17311)

weswigham · web-flow · commit 7cb8ce4346fc · 2017-07-20T10:09:55.000-07:00
* Fix exceptions on empty tuple errors

* Remove bonus semicolon

* Invert condition
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -2621,9 +2621,10 @@ namespace ts {
                                 return createTupleTypeNode(tupleConstituentNodes);
                             }
                         }
-                        if (!context.encounteredError && !(context.flags & NodeBuilderFlags.AllowEmptyTuple)) {
-                            context.encounteredError = true;
+                        if (context.encounteredError || (context.flags & NodeBuilderFlags.AllowEmptyTuple)) {
+                            return createTupleTypeNode([]);
                         }
+                        context.encounteredError = true;
                         return undefined;
                     }
                     else {
diff --git a/tests/baselines/reference/anyIndexedAccessArrayNoException.errors.txt b/tests/baselines/reference/anyIndexedAccessArrayNoException.errors.txt
@@ -0,0 +1,8 @@
+tests/cases/compiler/anyIndexedAccessArrayNoException.ts(1,12): error TS2538: Type '[]' cannot be used as an index type.
+
+
+==== tests/cases/compiler/anyIndexedAccessArrayNoException.ts (1 errors) ====
+    var x: any[[]];
+               ~~
+!!! error TS2538: Type '[]' cannot be used as an index type.
+    
diff --git a/tests/baselines/reference/anyIndexedAccessArrayNoException.js b/tests/baselines/reference/anyIndexedAccessArrayNoException.js
@@ -0,0 +1,6 @@
+//// [anyIndexedAccessArrayNoException.ts]
+var x: any[[]];
+
+
+//// [anyIndexedAccessArrayNoException.js]
+var x;
diff --git a/tests/baselines/reference/promiseEmptyTupleNoException.errors.txt b/tests/baselines/reference/promiseEmptyTupleNoException.errors.txt
@@ -0,0 +1,20 @@
+tests/cases/compiler/promiseEmptyTupleNoException.ts(1,38): error TS1122: A tuple type element list cannot be empty.
+tests/cases/compiler/promiseEmptyTupleNoException.ts(3,3): error TS2322: Type 'any[]' is not assignable to type '[]'.
+  Types of property 'pop' are incompatible.
+    Type '() => any' is not assignable to type '() => never'.
+      Type 'any' is not assignable to type 'never'.
+
+
+==== tests/cases/compiler/promiseEmptyTupleNoException.ts (2 errors) ====
+    export async function get(): Promise<[]> {
+                                         ~~
+!!! error TS1122: A tuple type element list cannot be empty.
+      let emails = [];
+      return emails;
+      ~~~~~~~~~~~~~~
+!!! error TS2322: Type 'any[]' is not assignable to type '[]'.
+!!! error TS2322:   Types of property 'pop' are incompatible.
+!!! error TS2322:     Type '() => any' is not assignable to type '() => never'.
+!!! error TS2322:       Type 'any' is not assignable to type 'never'.
+    }
+    
diff --git a/tests/baselines/reference/promiseEmptyTupleNoException.js b/tests/baselines/reference/promiseEmptyTupleNoException.js
@@ -0,0 +1,12 @@
+//// [promiseEmptyTupleNoException.ts]
+export async function get(): Promise<[]> {
+  let emails = [];
+  return emails;
+}
+
+
+//// [promiseEmptyTupleNoException.js]
+export async function get() {
+    let emails = [];
+    return emails;
+}
diff --git a/tests/cases/compiler/anyIndexedAccessArrayNoException.ts b/tests/cases/compiler/anyIndexedAccessArrayNoException.ts
@@ -0,0 +1 @@
+var x: any[[]];
diff --git a/tests/cases/compiler/promiseEmptyTupleNoException.ts b/tests/cases/compiler/promiseEmptyTupleNoException.ts
@@ -0,0 +1,5 @@
+// @target: es2017
+export async function get(): Promise<[]> {
+  let emails = [];
+  return emails;
+}

Original file line number	Diff line number	Diff line change
`@@ -2621,9 +2621,10 @@ namespace ts {`
`2621`	`2621`	`return createTupleTypeNode(tupleConstituentNodes);`
`2622`	`2622`	`}`
`2623`	`2623`	`}`
`2624`		`- if (!context.encounteredError && !(context.flags & NodeBuilderFlags.AllowEmptyTuple)) {`
`2625`		`- context.encounteredError = true;`
	`2624`	`+ if (context.encounteredError \|\| (context.flags & NodeBuilderFlags.AllowEmptyTuple)) {`
	`2625`	`+ return createTupleTypeNode([]);`
`2626`	`2626`	`}`
	`2627`	`+ context.encounteredError = true;`
`2627`	`2628`	`return undefined;`
`2628`	`2629`	`}`
`2629`	`2630`	`else {`