Merge branch 'tycho01:13126-empty-tuple' into empty-tuple

Author: lefb766

src/compiler/checker.ts

@@ -337,7 +337,6 @@ namespace ts {
 
         const emptyStringType = getLiteralType("");
         const zeroType = getLiteralType(0);
-        const emptyTupleType = createTupleType([]);
 
         const resolutionTargets: TypeSystemEntity[] = [];
         const resolutionResults: boolean[] = [];
@@ -2660,7 +2659,7 @@ namespace ts {
                         return createArrayTypeNode(elementType);
                     }
                     else if (type.target.objectFlags & ObjectFlags.Tuple) {
-                        const tupleConstituentNodes = mapToTypeNodes(typeArguments.slice(0, getTypeReferenceArity(type)), context) || [];
+                        const tupleConstituentNodes = mapToTypeNodes(typeArguments.slice(0, getTypeReferenceArity(type)), context);
                         return createTupleTypeNode(tupleConstituentNodes);
                     }
                     else {
@@ -10048,7 +10047,7 @@ namespace ts {
         }
 
         function isTupleLikeType(type: Type): boolean {
-            return !!getPropertyOfType(type, "0" as __String) || type === emptyTupleType;
+            return !!getPropertyOfType(type, "0" as __String) || type === getTupleTypeOfArity(0);
         }
 
         function isUnitType(type: Type): boolean {

tests/baselines/reference/anyIndexedAccessArrayNoException.errors.txt

@@ -1,11 +1,8 @@
-tests/cases/compiler/anyIndexedAccessArrayNoException.ts(1,12): error TS1122: A tuple type element list cannot be empty.
 tests/cases/compiler/anyIndexedAccessArrayNoException.ts(1,12): error TS2538: Type '[]' cannot be used as an index type.
 
 
-==== tests/cases/compiler/anyIndexedAccessArrayNoException.ts (2 errors) ====
+==== tests/cases/compiler/anyIndexedAccessArrayNoException.ts (1 errors) ====
     var x: any[[]];
                ~~
-!!! error TS1122: A tuple type element list cannot be empty.
-               ~~
 !!! error TS2538: Type '[]' cannot be used as an index type.
 

tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt

@@ -15,7 +15,6 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(35,21): error
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(36,21): error TS2538: Type 'boolean' cannot be used as an index type.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(41,31): error TS2538: Type 'boolean' cannot be used as an index type.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(46,16): error TS2538: Type 'boolean' cannot be used as an index type.
-tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(49,12): error TS1122: A tuple type element list cannot be empty.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(63,33): error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(64,33): error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
   Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
@@ -29,7 +28,7 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(76,5): error
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(77,5): error TS2322: Type 'keyof (T & U)' is not assignable to type 'keyof (T | U)'.
 
 
-==== tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts (25 errors) ====
+==== tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts (24 errors) ====
     class Shape {
         name: string;
         width: number;
@@ -113,8 +112,6 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(77,5): error
 
     type T60 = {}["toString"];
     type T61 = []["toString"];
-               ~~
-!!! error TS1122: A tuple type element list cannot be empty.
 
     declare let cond: boolean;
 

tests/baselines/reference/promiseEmptyTupleNoException.errors.txt

@@ -1,14 +1,11 @@
-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) ====
+==== tests/cases/compiler/promiseEmptyTupleNoException.ts (1 errors) ====
     export async function get(): Promise<[]> {
-                                         ~~
-!!! error TS1122: A tuple type element list cannot be empty.
       let emails = [];
       return emails;
       ~~~~~~~~~~~~~~

tests/baselines/reference/tupleTypes.errors.txt

@@ -89,7 +89,7 @@ tests/cases/compiler/tupleTypes.ts(65,1): error TS2322: Type '[number, string]'
     var tt0: number;
     var tt1 = tt[1];
     var tt1: string;
-    var tt2 = tt[2]; 
+    var tt2 = tt[2];
     var tt2: number | string;
 
     tt = tuple2(1, undefined);

tests/baselines/reference/tupleTypes.js

@@ -40,7 +40,7 @@ var tt0 = tt[0];
 var tt0: number;
 var tt1 = tt[1];
 var tt1: string;
-var tt2 = tt[2]; 
+var tt2 = tt[2];
 var tt2: number | string;
 
 tt = tuple2(1, undefined);

tests/cases/compiler/tupleTypes.ts

@@ -39,7 +39,7 @@ var tt0 = tt[0];
 var tt0: number;
 var tt1 = tt[1];
 var tt1: string;
-var tt2 = tt[2]; 
+var tt2 = tt[2];
 var tt2: number | string;
 
 tt = tuple2(1, undefined);

tests/cases/compiler/tupleTypesStrictNullChecks.ts

@@ -1,7 +1,7 @@
-// @strictNullChecks: true
-
-var et: [] = [];
-var et0 = et[0];  // never
-var et0: never;
-
-et = [];    // Ok
+// @strictNullChecks: true
+
+var et: [] = [];
+var et0 = et[0];  // never
+var et0: never;
+
+et = [];    // Ok