Add empty tuple type

lefb766 · lefb766 · commit 0e7ffda5fafb · 2017-03-14T18:25:09.000+09:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -294,6 +294,7 @@ namespace ts {
 
         const emptyStringType = getLiteralTypeForText(TypeFlags.StringLiteral, "");
         const zeroType = getLiteralTypeForText(TypeFlags.NumberLiteral, "0");
+        const emptyTupleType = createTupleType([]);
 
         const resolutionTargets: TypeSystemEntity[] = [];
         const resolutionResults: boolean[] = [];
@@ -8910,7 +8911,11 @@ namespace ts {
         }
 
         function isTupleLikeType(type: Type): boolean {
-            return !!getPropertyOfType(type, "0");
+            return !!getPropertyOfType(type, "0") || isEmptyTupleType(type);
+        }
+
+        function isEmptyTupleType(type: Type): boolean {
+            return emptyTupleType.id == type.id;
         }
 
         function isUnitType(type: Type): boolean {
@@ -12191,9 +12196,7 @@ namespace ts {
                             }
                         }
                     }
-                    if (elementTypes.length) {
-                        return createTupleType(elementTypes);
-                    }
+                    return createTupleType(elementTypes);
                 }
             }
             return createArrayType(elementTypes.length ?
@@ -17115,10 +17118,7 @@ namespace ts {
 
         function checkTupleType(node: TupleTypeNode) {
             // Grammar checking
-            const hasErrorFromDisallowedTrailingComma = checkGrammarForDisallowedTrailingComma(node.elementTypes);
-            if (!hasErrorFromDisallowedTrailingComma && node.elementTypes.length === 0) {
-                grammarErrorOnNode(node, Diagnostics.A_tuple_type_element_list_cannot_be_empty);
-            }
+            checkGrammarForDisallowedTrailingComma(node.elementTypes);
 
             forEach(node.elementTypes, checkSourceElement);
         }
diff --git a/tests/baselines/reference/TupleType3.errors.txt b/tests/baselines/reference/TupleType3.errors.txt
diff --git a/tests/baselines/reference/TupleType3.symbols b/tests/baselines/reference/TupleType3.symbols
@@ -0,0 +1,4 @@
+=== tests/cases/conformance/parser/ecmascript5/TupleTypes/TupleType3.ts ===
+var v: []
+>v : Symbol(v, Decl(TupleType3.ts, 0, 3))
+
diff --git a/tests/baselines/reference/TupleType3.types b/tests/baselines/reference/TupleType3.types
@@ -0,0 +1,4 @@
+=== tests/cases/conformance/parser/ecmascript5/TupleTypes/TupleType3.ts ===
+var v: []
+>v : []
+
diff --git a/tests/baselines/reference/arrayLiterals3.errors.txt b/tests/baselines/reference/arrayLiterals3.errors.txt
@@ -1,5 +1,5 @@
-tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(10,5): error TS2322: Type 'undefined[]' is not assignable to type '[any, any, any]'.
-  Property '0' is missing in type 'undefined[]'.
+tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(10,5): error TS2322: Type '[]' is not assignable to type '[any, any, any]'.
+  Property '0' is missing in type '[]'.
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(11,5): error TS2322: Type '["string", number, boolean]' is not assignable to type '[boolean, string, number]'.
   Type '"string"' is not assignable to type 'boolean'.
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(17,5): error TS2322: Type '[number, number, string, boolean]' is not assignable to type '[number, number]'.
@@ -32,8 +32,8 @@ tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(34,5): error
     
     var a0: [any, any, any] = [];                             // Error
         ~~
-!!! error TS2322: Type 'undefined[]' is not assignable to type '[any, any, any]'.
-!!! error TS2322:   Property '0' is missing in type 'undefined[]'.
+!!! error TS2322: Type '[]' is not assignable to type '[any, any, any]'.
+!!! error TS2322:   Property '0' is missing in type '[]'.
     var a1: [boolean, string, number] = ["string", 1, true];  // Error
         ~~
 !!! error TS2322: Type '["string", number, boolean]' is not assignable to type '[boolean, string, number]'.
diff --git a/tests/baselines/reference/emptyTuplesTypeAssertion01.errors.txt b/tests/baselines/reference/emptyTuplesTypeAssertion01.errors.txt
diff --git a/tests/baselines/reference/emptyTuplesTypeAssertion01.symbols b/tests/baselines/reference/emptyTuplesTypeAssertion01.symbols
@@ -0,0 +1,9 @@
+=== tests/cases/conformance/types/tuple/emptyTuples/emptyTuplesTypeAssertion01.ts ===
+
+let x = <[]>[];
+>x : Symbol(x, Decl(emptyTuplesTypeAssertion01.ts, 1, 3))
+
+let y = x[0];
+>y : Symbol(y, Decl(emptyTuplesTypeAssertion01.ts, 2, 3))
+>x : Symbol(x, Decl(emptyTuplesTypeAssertion01.ts, 1, 3))
+
diff --git a/tests/baselines/reference/emptyTuplesTypeAssertion01.types b/tests/baselines/reference/emptyTuplesTypeAssertion01.types
@@ -0,0 +1,13 @@
+=== tests/cases/conformance/types/tuple/emptyTuples/emptyTuplesTypeAssertion01.ts ===
+
+let x = <[]>[];
+>x : []
+><[]>[] : []
+>[] : []
+
+let y = x[0];
+>y : never
+>x[0] : never
+>x : []
+>0 : 0
+
diff --git a/tests/baselines/reference/emptyTuplesTypeAssertion02.errors.txt b/tests/baselines/reference/emptyTuplesTypeAssertion02.errors.txt
diff --git a/tests/baselines/reference/emptyTuplesTypeAssertion02.symbols b/tests/baselines/reference/emptyTuplesTypeAssertion02.symbols
@@ -0,0 +1,9 @@
+=== tests/cases/conformance/types/tuple/emptyTuples/emptyTuplesTypeAssertion02.ts ===
+
+let x = [] as [];
+>x : Symbol(x, Decl(emptyTuplesTypeAssertion02.ts, 1, 3))
+
+let y = x[0];
+>y : Symbol(y, Decl(emptyTuplesTypeAssertion02.ts, 2, 3))
+>x : Symbol(x, Decl(emptyTuplesTypeAssertion02.ts, 1, 3))
+
diff --git a/tests/baselines/reference/emptyTuplesTypeAssertion02.types b/tests/baselines/reference/emptyTuplesTypeAssertion02.types
@@ -0,0 +1,13 @@
+=== tests/cases/conformance/types/tuple/emptyTuples/emptyTuplesTypeAssertion02.ts ===
+
+let x = [] as [];
+>x : []
+>[] as [] : []
+>[] : []
+
+let y = x[0];
+>y : never
+>x[0] : never
+>x : []
+>0 : 0
+
diff --git a/tests/baselines/reference/tupleTypes.errors.txt b/tests/baselines/reference/tupleTypes.errors.txt
@@ -1,31 +1,40 @@
-tests/cases/compiler/tupleTypes.ts(1,9): error TS1122: A tuple type element list cannot be empty.
-tests/cases/compiler/tupleTypes.ts(14,1): error TS2322: Type 'undefined[]' is not assignable to type '[number, string]'.
-  Property '0' is missing in type 'undefined[]'.
+tests/cases/compiler/tupleTypes.ts(14,1): error TS2322: Type '[]' is not assignable to type '[number, string]'.
+  Property '0' is missing in type '[]'.
 tests/cases/compiler/tupleTypes.ts(15,1): error TS2322: Type '[number]' is not assignable to type '[number, string]'.
   Property '1' is missing in type '[number]'.
 tests/cases/compiler/tupleTypes.ts(17,1): error TS2322: Type '[string, number]' is not assignable to type '[number, string]'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/tupleTypes.ts(41,1): error TS2322: Type 'undefined[]' is not assignable to type '[number, string]'.
-tests/cases/compiler/tupleTypes.ts(47,1): error TS2322: Type '[number, string]' is not assignable to type 'number[]'.
+tests/cases/compiler/tupleTypes.ts(25,1): error TS2322: Type '[number]' is not assignable to type '[]'.
+  Types of property 'pop' are incompatible.
+    Type '() => number' is not assignable to type '() => never'.
+      Type 'number' is not assignable to type 'never'.
+tests/cases/compiler/tupleTypes.ts(48,1): error TS2322: Type '[]' is not assignable to type '[number, string]'.
+tests/cases/compiler/tupleTypes.ts(55,1): error TS2322: Type '[number, string]' is not assignable to type 'number[]'.
   Types of property 'pop' are incompatible.
     Type '() => string | number' is not assignable to type '() => number'.
       Type 'string | number' is not assignable to type 'number'.
         Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/tupleTypes.ts(49,1): error TS2322: Type '[number, {}]' is not assignable to type 'number[]'.
+tests/cases/compiler/tupleTypes.ts(57,1): error TS2322: Type '[number, {}]' is not assignable to type 'number[]'.
   Types of property 'pop' are incompatible.
     Type '() => number | {}' is not assignable to type '() => number'.
       Type 'number | {}' is not assignable to type 'number'.
         Type '{}' is not assignable to type 'number'.
-tests/cases/compiler/tupleTypes.ts(50,1): error TS2322: Type '[number, number]' is not assignable to type '[number, string]'.
+tests/cases/compiler/tupleTypes.ts(59,1): error TS2322: Type '[number, number]' is not assignable to type '[number, string]'.
   Type 'number' is not assignable to type 'string'.
-tests/cases/compiler/tupleTypes.ts(51,1): error TS2322: Type '[number, {}]' is not assignable to type '[number, string]'.
+tests/cases/compiler/tupleTypes.ts(60,1): error TS2322: Type '[number, {}]' is not assignable to type '[number, string]'.
   Type '{}' is not assignable to type 'string'.
+tests/cases/compiler/tupleTypes.ts(61,1): error TS2322: Type '[]' is not assignable to type '[number, string]'.
+tests/cases/compiler/tupleTypes.ts(64,1): error TS2322: Type '[]' is not assignable to type '[number, {}]'.
+  Property '0' is missing in type '[]'.
+tests/cases/compiler/tupleTypes.ts(65,1): error TS2322: Type '[number, string]' is not assignable to type '[]'.
+  Types of property 'pop' are incompatible.
+    Type '() => string | number' is not assignable to type '() => never'.
+      Type 'string | number' is not assignable to type 'never'.
+        Type 'string' is not assignable to type 'never'.
 
 
-==== tests/cases/compiler/tupleTypes.ts (9 errors) ====
-    var v1: [];  // Error
-            ~~
-!!! error TS1122: A tuple type element list cannot be empty.
+==== tests/cases/compiler/tupleTypes.ts (12 errors) ====
+    var v1: [];
     var v2: [number];
     var v3: [number, string];
     var v4: [number, [string, string]];
@@ -40,8 +49,8 @@ tests/cases/compiler/tupleTypes.ts(51,1): error TS2322: Type '[number, {}]' is n
     
     t = [];               // Error
     ~
-!!! error TS2322: Type 'undefined[]' is not assignable to type '[number, string]'.
-!!! error TS2322:   Property '0' is missing in type 'undefined[]'.
+!!! error TS2322: Type '[]' is not assignable to type '[number, string]'.
+!!! error TS2322:   Property '0' is missing in type '[]'.
     t = [1];              // Error
     ~
 !!! error TS2322: Type '[number]' is not assignable to type '[number, string]'.
@@ -53,6 +62,18 @@ tests/cases/compiler/tupleTypes.ts(51,1): error TS2322: Type '[number, {}]' is n
 !!! error TS2322:   Type 'string' is not assignable to type 'number'.
     t = [1, "hello", 2];  // Ok
     
+    var et: [];
+    var et0 = et[0];  // never
+    var et0: never;
+    
+    et = [];    // Ok
+    et = [1];   // Error
+    ~~
+!!! error TS2322: Type '[number]' is not assignable to type '[]'.
+!!! error TS2322:   Types of property 'pop' are incompatible.
+!!! error TS2322:     Type '() => number' is not assignable to type '() => never'.
+!!! error TS2322:       Type 'number' is not assignable to type 'never'.
+    
     var tf: [string, (x: string) => number] = ["hello", x => x.length];
     
     declare function ff<T, U>(a: T, b: [T, (x: T) => U]): U;
@@ -76,12 +97,13 @@ tests/cases/compiler/tupleTypes.ts(51,1): error TS2322: Type '[number, {}]' is n
     tt = [undefined, undefined];
     tt = [];  // Error
     ~~
-!!! error TS2322: Type 'undefined[]' is not assignable to type '[number, string]'.
+!!! error TS2322: Type '[]' is not assignable to type '[number, string]'.
     
     var a: number[];
     var a1: [number, string];
     var a2: [number, number];
     var a3: [number, {}];
+    var a4: [];
     a = a1;   // Error
     ~
 !!! error TS2322: Type '[number, string]' is not assignable to type 'number[]'.
@@ -97,6 +119,7 @@ tests/cases/compiler/tupleTypes.ts(51,1): error TS2322: Type '[number, {}]' is n
 !!! error TS2322:     Type '() => number | {}' is not assignable to type '() => number'.
 !!! error TS2322:       Type 'number | {}' is not assignable to type 'number'.
 !!! error TS2322:         Type '{}' is not assignable to type 'number'.
+    a = a4;
     a1 = a2;  // Error
     ~~
 !!! error TS2322: Type '[number, number]' is not assignable to type '[number, string]'.
@@ -105,6 +128,20 @@ tests/cases/compiler/tupleTypes.ts(51,1): error TS2322: Type '[number, {}]' is n
     ~~
 !!! error TS2322: Type '[number, {}]' is not assignable to type '[number, string]'.
 !!! error TS2322:   Type '{}' is not assignable to type 'string'.
+    a1 = a4;  // Error
+    ~~
+!!! error TS2322: Type '[]' is not assignable to type '[number, string]'.
     a3 = a1;
     a3 = a2;
+    a3 = a4;  // Error
+    ~~
+!!! error TS2322: Type '[]' is not assignable to type '[number, {}]'.
+!!! error TS2322:   Property '0' is missing in type '[]'.
+    a4 = a1;  // Error
+    ~~
+!!! error TS2322: Type '[number, string]' is not assignable to type '[]'.
+!!! error TS2322:   Types of property 'pop' are incompatible.
+!!! error TS2322:     Type '() => string | number' is not assignable to type '() => never'.
+!!! error TS2322:       Type 'string | number' is not assignable to type 'never'.
+!!! error TS2322:         Type 'string' is not assignable to type 'never'.
     
diff --git a/tests/baselines/reference/tupleTypes.js b/tests/baselines/reference/tupleTypes.js
@@ -1,5 +1,5 @@
 //// [tupleTypes.ts]
-var v1: [];  // Error
+var v1: [];
 var v2: [number];
 var v3: [number, string];
 var v4: [number, [string, string]];
@@ -18,6 +18,13 @@ t = [1, "hello"];     // Ok
 t = ["hello", 1];     // Error
 t = [1, "hello", 2];  // Ok
 
+var et: [];
+var et0 = et[0];  // never
+var et0: never;
+
+et = [];    // Ok
+et = [1];   // Error
+
 var tf: [string, (x: string) => number] = ["hello", x => x.length];
 
 declare function ff<T, U>(a: T, b: [T, (x: T) => U]): U;
@@ -45,17 +52,22 @@ var a: number[];
 var a1: [number, string];
 var a2: [number, number];
 var a3: [number, {}];
+var a4: [];
 a = a1;   // Error
 a = a2;
 a = a3;   // Error
+a = a4;
 a1 = a2;  // Error
 a1 = a3;  // Error
+a1 = a4;  // Error
 a3 = a1;
 a3 = a2;
+a3 = a4;  // Error
+a4 = a1;  // Error
 
 
 //// [tupleTypes.js]
-var v1; // Error
+var v1;
 var v2;
 var v3;
 var v4;
@@ -71,6 +83,11 @@ t = [1]; // Error
 t = [1, "hello"]; // Ok
 t = ["hello", 1]; // Error
 t = [1, "hello", 2]; // Ok
+var et;
+var et0 = et[0]; // never
+var et0;
+et = []; // Ok
+et = [1]; // Error
 var tf = ["hello", function (x) { return x.length; }];
 var ff1 = ff("hello", ["foo", function (x) { return x.length; }]);
 var ff1;
@@ -92,10 +109,15 @@ var a;
 var a1;
 var a2;
 var a3;
+var a4;
 a = a1; // Error
 a = a2;
 a = a3; // Error
+a = a4;
 a1 = a2; // Error
 a1 = a3; // Error
+a1 = a4; // Error
 a3 = a1;
 a3 = a2;
+a3 = a4; // Error
+a4 = a1; // Error
diff --git a/tests/cases/compiler/tupleTypes.ts b/tests/cases/compiler/tupleTypes.ts
@@ -1,4 +1,4 @@
-var v1: [];  // Error
+var v1: [];
 var v2: [number];
 var v3: [number, string];
 var v4: [number, [string, string]];
@@ -17,6 +17,13 @@ t = [1, "hello"];     // Ok
 t = ["hello", 1];     // Error
 t = [1, "hello", 2];  // Ok
 
+var et: [];
+var et0 = et[0];  // never
+var et0: never;
+
+et = [];    // Ok
+et = [1];   // Error
+
 var tf: [string, (x: string) => number] = ["hello", x => x.length];
 
 declare function ff<T, U>(a: T, b: [T, (x: T) => U]): U;
@@ -44,10 +51,15 @@ var a: number[];
 var a1: [number, string];
 var a2: [number, number];
 var a3: [number, {}];
+var a4: [];
 a = a1;   // Error
 a = a2;
 a = a3;   // Error
+a = a4;
 a1 = a2;  // Error
 a1 = a3;  // Error
+a1 = a4;  // Error
 a3 = a1;
 a3 = a2;
+a3 = a4;  // Error
+a4 = a1;  // Error

Original file line number	Diff line number	Diff line change
`@@ -294,6 +294,7 @@ namespace ts {`
`294`	`294`
`295`	`295`	`const emptyStringType = getLiteralTypeForText(TypeFlags.StringLiteral, "");`
`296`	`296`	`const zeroType = getLiteralTypeForText(TypeFlags.NumberLiteral, "0");`
	`297`	`+ const emptyTupleType = createTupleType([]);`
`297`	`298`
`298`	`299`	`const resolutionTargets: TypeSystemEntity[] = [];`
`299`	`300`	`const resolutionResults: boolean[] = [];`
`@@ -8910,7 +8911,11 @@ namespace ts {`
`8910`	`8911`	`}`
`8911`	`8912`
`8912`	`8913`	`function isTupleLikeType(type: Type): boolean {`
`8913`		`- return !!getPropertyOfType(type, "0");`
	`8914`	`+ return !!getPropertyOfType(type, "0") \|\| isEmptyTupleType(type);`
	`8915`	`+ }`
	`8916`	`+`
	`8917`	`+ function isEmptyTupleType(type: Type): boolean {`
	`8918`	`+ return emptyTupleType.id == type.id;`
`8914`	`8919`	`}`
`8915`	`8920`
`8916`	`8921`	`function isUnitType(type: Type): boolean {`
`@@ -12191,9 +12196,7 @@ namespace ts {`
`12191`	`12196`	`}`
`12192`	`12197`	`}`
`12193`	`12198`	`}`
`12194`		`- if (elementTypes.length) {`
`12195`		`- return createTupleType(elementTypes);`
`12196`		`- }`
	`12199`	`+ return createTupleType(elementTypes);`
`12197`	`12200`	`}`
`12198`	`12201`	`}`
`12199`	`12202`	`return createArrayType(elementTypes.length ?`
`@@ -17115,10 +17118,7 @@ namespace ts {`
`17115`	`17118`
`17116`	`17119`	`function checkTupleType(node: TupleTypeNode) {`
`17117`	`17120`	`// Grammar checking`
`17118`		`- const hasErrorFromDisallowedTrailingComma = checkGrammarForDisallowedTrailingComma(node.elementTypes);`
`17119`		`- if (!hasErrorFromDisallowedTrailingComma && node.elementTypes.length === 0) {`
`17120`		`- grammarErrorOnNode(node, Diagnostics.A_tuple_type_element_list_cannot_be_empty);`
`17121`		`- }`
	`17121`	`+ checkGrammarForDisallowedTrailingComma(node.elementTypes);`
`17122`	`17122`
`17123`	`17123`	`forEach(node.elementTypes, checkSourceElement);`
`17124`	`17124`	`}`
-Original file line number
+Diff line change
@@ @@ -0,0 +1,4 @@ @@
 +=== tests/cases/conformance/parser/ecmascript5/TupleTypes/TupleType3.ts ===
 +var v: []
 +>v : []
++