Merge pull request microsoft#16736 from DickvdBrink/issue/15208

sandersn · web-flow · commit c51c2aecca4f · 2017-06-28T12:37:04.000-07:00
Also check TypeAlias for unused type parameters
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -19470,6 +19470,9 @@ namespace ts {
                         case SyntaxKind.ConstructorType:
                             checkUnusedTypeParameters(<FunctionLikeDeclaration>node);
                             break;
+                        case SyntaxKind.TypeAliasDeclaration:
+                            checkUnusedTypeParameters(<TypeAliasDeclaration>node);
+                            break;
                     }
                 }
             }
@@ -19547,7 +19550,7 @@ namespace ts {
             }
         }
 
-        function checkUnusedTypeParameters(node: ClassDeclaration | ClassExpression | FunctionDeclaration | MethodDeclaration | FunctionExpression | ArrowFunction | ConstructorDeclaration | SignatureDeclaration | InterfaceDeclaration) {
+        function checkUnusedTypeParameters(node: ClassDeclaration | ClassExpression | FunctionDeclaration | MethodDeclaration | FunctionExpression | ArrowFunction | ConstructorDeclaration | SignatureDeclaration | InterfaceDeclaration | TypeAliasDeclaration) {
             if (compilerOptions.noUnusedLocals && !isInAmbientContext(node)) {
                 if (node.typeParameters) {
                     // Only report errors on the last declaration for the type parameter container;
@@ -21252,6 +21255,7 @@ namespace ts {
             checkTypeNameIsReserved(node.name, Diagnostics.Type_alias_name_cannot_be_0);
             checkTypeParameters(node.typeParameters);
             checkSourceElement(node.type);
+            registerForUnusedIdentifiersCheck(node);
         }
 
         function computeEnumMemberValues(node: EnumDeclaration) {
diff --git a/tests/baselines/reference/unusedTypeParameters10.errors.txt b/tests/baselines/reference/unusedTypeParameters10.errors.txt
@@ -0,0 +1,9 @@
+tests/cases/compiler/unusedTypeParameters10.ts(1,12): error TS6133: 'T' is declared but never used.
+
+
+==== tests/cases/compiler/unusedTypeParameters10.ts (1 errors) ====
+    type Alias<T> = { };
+               ~
+!!! error TS6133: 'T' is declared but never used.
+    type Alias2<T> = { x: T };
+    
diff --git a/tests/baselines/reference/unusedTypeParameters10.js b/tests/baselines/reference/unusedTypeParameters10.js
@@ -0,0 +1,6 @@
+//// [unusedTypeParameters10.ts]
+type Alias<T> = { };
+type Alias2<T> = { x: T };
+
+
+//// [unusedTypeParameters10.js]
diff --git a/tests/cases/compiler/unusedTypeParameters10.ts b/tests/cases/compiler/unusedTypeParameters10.ts
@@ -0,0 +1,5 @@
+//@noUnusedLocals:true
+//@noUnusedParameters:true
+
+type Alias<T> = { };
+type Alias2<T> = { x: T };

Original file line number	Diff line number	Diff line change
`@@ -19470,6 +19470,9 @@ namespace ts {`
`19470`	`19470`	`case SyntaxKind.ConstructorType:`
`19471`	`19471`	`checkUnusedTypeParameters(<FunctionLikeDeclaration>node);`
`19472`	`19472`	`break;`
	`19473`	`+ case SyntaxKind.TypeAliasDeclaration:`
	`19474`	`+ checkUnusedTypeParameters(<TypeAliasDeclaration>node);`
	`19475`	`+ break;`
`19473`	`19476`	`}`
`19474`	`19477`	`}`
`19475`	`19478`	`}`
`@@ -19547,7 +19550,7 @@ namespace ts {`
`19547`	`19550`	`}`
`19548`	`19551`	`}`
`19549`	`19552`
`19550`		`- function checkUnusedTypeParameters(node: ClassDeclaration \| ClassExpression \| FunctionDeclaration \| MethodDeclaration \| FunctionExpression \| ArrowFunction \| ConstructorDeclaration \| SignatureDeclaration \| InterfaceDeclaration) {`
	`19553`	`+ function checkUnusedTypeParameters(node: ClassDeclaration \| ClassExpression \| FunctionDeclaration \| MethodDeclaration \| FunctionExpression \| ArrowFunction \| ConstructorDeclaration \| SignatureDeclaration \| InterfaceDeclaration \| TypeAliasDeclaration) {`
`19551`	`19554`	`if (compilerOptions.noUnusedLocals && !isInAmbientContext(node)) {`
`19552`	`19555`	`if (node.typeParameters) {`
`19553`	`19556`	`// Only report errors on the last declaration for the type parameter container;`
`@@ -21252,6 +21255,7 @@ namespace ts {`
`21252`	`21255`	`checkTypeNameIsReserved(node.name, Diagnostics.Type_alias_name_cannot_be_0);`
`21253`	`21256`	`checkTypeParameters(node.typeParameters);`
`21254`	`21257`	`checkSourceElement(node.type);`
	`21258`	`+ registerForUnusedIdentifiersCheck(node);`
`21255`	`21259`	`}`
`21256`	`21260`
`21257`	`21261`	`function computeEnumMemberValues(node: EnumDeclaration) {`