warn when generator function without any yield expression(#13847)

microsoft · Oct 31, 2017 · e4576ed · e4576ed
1 parent 8528667
commit e4576ed
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Showing 81 changed files with 284 additions and 144 deletions.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -17283,7 +17283,12 @@ namespace ts {
             else {
                 let types: Type[];
                 if (functionFlags & FunctionFlags.Generator) { // Generator or AsyncGenerator function
-                    types = concatenate(checkAndAggregateYieldOperandTypes(func, checkMode), checkAndAggregateReturnExpressionTypes(func, checkMode));
+                    const aggregatedYield = checkAndAggregateYieldOperandTypes(func, checkMode);
+                    const aggregatedReturn = checkAndAggregateReturnExpressionTypes(func, checkMode)
+                    if (aggregatedReturn.length && aggregatedYield.length === 0) {
+                        error(func, Diagnostics.A_generator_cannot_have_a_return_statement_and_no_yield_statements);
+                    }
+                    types = concatenate(aggregatedYield, aggregatedReturn);
                     if (!types || types.length === 0) {
                         const iterableIteratorAny = functionFlags & FunctionFlags.Async
                             ? createAsyncIterableIteratorType(anyType) // AsyncGenerator function
@@ -25071,7 +25076,7 @@ namespace ts {
                 if (isInAmbientContext(node)) {
                     return grammarErrorOnNode(node.asteriskToken, Diagnostics.Generators_are_not_allowed_in_an_ambient_context);
                 }
-                if (!node.body) {
+                else {
                     return grammarErrorOnNode(node.asteriskToken, Diagnostics.An_overload_signature_cannot_be_declared_as_a_generator);
                 }
             }

diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
@@ -911,6 +911,10 @@
         "category": "Error",
         "code": 1329
     },
+    "A generator cannot have a return statement and no yield statements.": {
+        "category": "Error",
+        "code": 1330
+    },
 
     "Duplicate identifier '{0}'.": {
         "category": "Error",

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.js
@@ -38,7 +38,6 @@ class C6 {
 //// [C7.ts]
 class C7 {
     async * f() {
-        return 1;
     }
 }
 //// [C8.ts]
@@ -215,7 +214,6 @@ var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _ar
 class C7 {
     f() {
         return __asyncGenerator(this, arguments, function* f_1() {
-            return 1;
         });
     }
 }

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.symbols b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.symbols
@@ -67,8 +67,6 @@ class C7 {
 
     async * f() {
 >f : Symbol(C7.f, Decl(C7.ts, 0, 10))
-
-        return 1;
     }
 }
 === tests/cases/conformance/emitter/es2015/asyncGenerators/C8.ts ===

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.types b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es2015.types
@@ -80,10 +80,7 @@ class C7 {
 >C7 : C7
 
     async * f() {
->f : () => AsyncIterableIterator<1>
-
-        return 1;
->1 : 1
+>f : () => AsyncIterableIterator<any>
     }
 }
 === tests/cases/conformance/emitter/es2015/asyncGenerators/C8.ts ===

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.js
@@ -38,7 +38,6 @@ class C6 {
 //// [C7.ts]
 class C7 {
     async * f() {
-        return 1;
     }
 }
 //// [C8.ts]
@@ -497,7 +496,7 @@ var C7 = /** @class */ (function () {
     C7.prototype.f = function () {
         return __asyncGenerator(this, arguments, function f_1() {
             return __generator(this, function (_a) {
-                return [2 /*return*/, 1];
+                return [2 /*return*/];
             });
         });
     };

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.symbols b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.symbols
@@ -67,8 +67,6 @@ class C7 {
 
     async * f() {
 >f : Symbol(C7.f, Decl(C7.ts, 0, 10))
-
-        return 1;
     }
 }
 === tests/cases/conformance/emitter/es5/asyncGenerators/C8.ts ===

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.types b/tests/baselines/reference/emitter.asyncGenerators.classMethods.es5.types
@@ -80,10 +80,7 @@ class C7 {
 >C7 : C7
 
     async * f() {
->f : () => AsyncIterableIterator<1>
-
-        return 1;
->1 : 1
+>f : () => AsyncIterableIterator<any>
     }
 }
 === tests/cases/conformance/emitter/es5/asyncGenerators/C8.ts ===

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.esnext.js b/tests/baselines/reference/emitter.asyncGenerators.classMethods.esnext.js
@@ -38,7 +38,6 @@ class C6 {
 //// [C7.ts]
 class C7 {
     async * f() {
-        return 1;
     }
 }
 //// [C8.ts]
@@ -98,7 +97,6 @@ class C6 {
 //// [C7.js]
 class C7 {
     async *f() {
-        return 1;
     }
 }
 //// [C8.js]

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.esnext.symbols b/tests/baselines/reference/emitter.asyncGenerators.classMethods.esnext.symbols
@@ -67,8 +67,6 @@ class C7 {
 
     async * f() {
 >f : Symbol(C7.f, Decl(C7.ts, 0, 10))
-
-        return 1;
     }
 }
 === tests/cases/conformance/emitter/esnext/asyncGenerators/C8.ts ===

diff --git a/tests/baselines/reference/emitter.asyncGenerators.classMethods.esnext.types b/tests/baselines/reference/emitter.asyncGenerators.classMethods.esnext.types
@@ -80,10 +80,7 @@ class C7 {
 >C7 : C7
 
     async * f() {
->f : () => AsyncIterableIterator<1>
-
-        return 1;
->1 : 1
+>f : () => AsyncIterableIterator<any>
     }
 }
 === tests/cases/conformance/emitter/esnext/asyncGenerators/C8.ts ===

diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.js
@@ -25,7 +25,6 @@ async function * f6() {
 }
 //// [F7.ts]
 async function * f7() {
-    return 1;
 }
 
 
@@ -171,6 +170,5 @@ var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _ar
 };
 function f7() {
     return __asyncGenerator(this, arguments, function* f7_1() {
-        return 1;
     });
 }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.symbols b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.symbols
@@ -40,7 +40,5 @@ async function * f6() {
 === tests/cases/conformance/emitter/es2015/asyncGenerators/F7.ts ===
 async function * f7() {
 >f7 : Symbol(f7, Decl(F7.ts, 0, 0))
-
-    return 1;
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.types b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es2015.types
@@ -53,9 +53,6 @@ async function * f6() {
 }
 === tests/cases/conformance/emitter/es2015/asyncGenerators/F7.ts ===
 async function * f7() {
->f7 : () => AsyncIterableIterator<1>
-
-    return 1;
->1 : 1
+>f7 : () => AsyncIterableIterator<any>
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.js
@@ -25,7 +25,6 @@ async function * f6() {
 }
 //// [F7.ts]
 async function * f7() {
-    return 1;
 }
 
 
@@ -433,7 +432,7 @@ var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _ar
 function f7() {
     return __asyncGenerator(this, arguments, function f7_1() {
         return __generator(this, function (_a) {
-            return [2 /*return*/, 1];
+            return [2 /*return*/];
         });
     });
 }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.symbols b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.symbols
@@ -40,7 +40,5 @@ async function * f6() {
 === tests/cases/conformance/emitter/es5/asyncGenerators/F7.ts ===
 async function * f7() {
 >f7 : Symbol(f7, Decl(F7.ts, 0, 0))
-
-    return 1;
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.types b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.es5.types
@@ -53,9 +53,6 @@ async function * f6() {
 }
 === tests/cases/conformance/emitter/es5/asyncGenerators/F7.ts ===
 async function * f7() {
->f7 : () => AsyncIterableIterator<1>
-
-    return 1;
->1 : 1
+>f7 : () => AsyncIterableIterator<any>
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.esnext.js b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.esnext.js
@@ -25,7 +25,6 @@ async function * f6() {
 }
 //// [F7.ts]
 async function * f7() {
-    return 1;
 }
 
 
@@ -54,5 +53,4 @@ async function* f6() {
 }
 //// [F7.js]
 async function* f7() {
-    return 1;
 }
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.esnext.symbols b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.esnext.symbols
@@ -40,7 +40,5 @@ async function * f6() {
 === tests/cases/conformance/emitter/esnext/asyncGenerators/F7.ts ===
 async function * f7() {
 >f7 : Symbol(f7, Decl(F7.ts, 0, 0))
-
-    return 1;
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.esnext.types b/tests/baselines/reference/emitter.asyncGenerators.functionDeclarations.esnext.types
@@ -53,9 +53,6 @@ async function * f6() {
 }
 === tests/cases/conformance/emitter/esnext/asyncGenerators/F7.ts ===
 async function * f7() {
->f7 : () => AsyncIterableIterator<1>
-
-    return 1;
->1 : 1
+>f7 : () => AsyncIterableIterator<any>
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.js
@@ -25,7 +25,6 @@ const f6 = async function * () {
 }
 //// [F7.ts]
 const f7 = async function * () {
-    return 1;
 }
 
 
@@ -171,6 +170,5 @@ var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _ar
 };
 const f7 = function () {
     return __asyncGenerator(this, arguments, function* () {
-        return 1;
     });
 };
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.symbols b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.symbols
@@ -40,7 +40,5 @@ const f6 = async function * () {
 === tests/cases/conformance/emitter/es2015/asyncGenerators/F7.ts ===
 const f7 = async function * () {
 >f7 : Symbol(f7, Decl(F7.ts, 0, 5))
-
-    return 1;
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.types b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es2015.types
@@ -59,10 +59,7 @@ const f6 = async function * () {
 }
 === tests/cases/conformance/emitter/es2015/asyncGenerators/F7.ts ===
 const f7 = async function * () {
->f7 : () => AsyncIterableIterator<1>
->async function * () {    return 1;} : () => AsyncIterableIterator<1>
-
-    return 1;
->1 : 1
+>f7 : () => AsyncIterableIterator<any>
+>async function * () {} : () => AsyncIterableIterator<any>
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.js
@@ -25,7 +25,6 @@ const f6 = async function * () {
 }
 //// [F7.ts]
 const f7 = async function * () {
-    return 1;
 }
 
 
@@ -433,7 +432,7 @@ var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _ar
 var f7 = function () {
     return __asyncGenerator(this, arguments, function () {
         return __generator(this, function (_a) {
-            return [2 /*return*/, 1];
+            return [2 /*return*/];
         });
     });
 };
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.symbols b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.symbols
@@ -40,7 +40,5 @@ const f6 = async function * () {
 === tests/cases/conformance/emitter/es5/asyncGenerators/F7.ts ===
 const f7 = async function * () {
 >f7 : Symbol(f7, Decl(F7.ts, 0, 5))
-
-    return 1;
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.types b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.es5.types
@@ -59,10 +59,7 @@ const f6 = async function * () {
 }
 === tests/cases/conformance/emitter/es5/asyncGenerators/F7.ts ===
 const f7 = async function * () {
->f7 : () => AsyncIterableIterator<1>
->async function * () {    return 1;} : () => AsyncIterableIterator<1>
-
-    return 1;
->1 : 1
+>f7 : () => AsyncIterableIterator<any>
+>async function * () {} : () => AsyncIterableIterator<any>
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.esnext.js b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.esnext.js
@@ -25,7 +25,6 @@ const f6 = async function * () {
 }
 //// [F7.ts]
 const f7 = async function * () {
-    return 1;
 }
 
 
@@ -54,5 +53,4 @@ const f6 = async function* () {
 };
 //// [F7.js]
 const f7 = async function* () {
-    return 1;
 };
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.esnext.symbols b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.esnext.symbols
@@ -40,7 +40,5 @@ const f6 = async function * () {
 === tests/cases/conformance/emitter/esnext/asyncGenerators/F7.ts ===
 const f7 = async function * () {
 >f7 : Symbol(f7, Decl(F7.ts, 0, 5))
-
-    return 1;
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.esnext.types b/tests/baselines/reference/emitter.asyncGenerators.functionExpressions.esnext.types
@@ -59,10 +59,7 @@ const f6 = async function * () {
 }
 === tests/cases/conformance/emitter/esnext/asyncGenerators/F7.ts ===
 const f7 = async function * () {
->f7 : () => AsyncIterableIterator<1>
->async function * () {    return 1;} : () => AsyncIterableIterator<1>
-
-    return 1;
->1 : 1
+>f7 : () => AsyncIterableIterator<any>
+>async function * () {} : () => AsyncIterableIterator<any>
 }
 
diff --git a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.js
@@ -38,7 +38,6 @@ const o6 = {
 //// [O7.ts]
 const o7 = {
     async * f() {
-        return 1;
     }
 }
 
@@ -198,7 +197,6 @@ var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _ar
 const o7 = {
     f() {
         return __asyncGenerator(this, arguments, function* f_1() {
-            return 1;
         });
     }
 };
diff --git a/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.symbols b/tests/baselines/reference/emitter.asyncGenerators.objectLiteralMethods.es2015.symbols
@@ -67,8 +67,6 @@ const o7 = {
 
     async * f() {
 >f : Symbol(f, Decl(O7.ts, 0, 12))
-
-        return 1;
     }
 }