Fix: Mark call expression type parameters as used (typescript-eslint#89)

Author: timothykang

Diff for: packages/eslint-plugin-typescript/lib/rules/no-unused-vars.js

@@ -271,6 +271,14 @@ module.exports = {
             FunctionExpression: markFunctionReturnTypeAsUsed,
             ArrowFunctionExpression: markFunctionReturnTypeAsUsed,
 
+            CallExpression(node) {
+                if (node.typeParameters && node.typeParameters.params) {
+                    node.typeParameters.params.forEach(
+                        markTypeAnnotationAsUsed
+                    );
+                }
+            },
+
             Decorator: markDecoratorAsUsed,
             TSInterfaceHeritage: markExtendedInterfaceAsUsed,
 

Diff for: packages/eslint-plugin-typescript/tests/lib/rules/no-unused-vars.js

@@ -184,6 +184,36 @@ ruleTester.run("no-unused-vars", ruleNoUnusedVars, {
             ].join("\n"),
             parser
         },
+        {
+            code: [
+                "import { Foo } from 'foo'",
+                "function bar<T>() {}",
+                "bar<Foo>()"
+            ].join("\n"),
+            parser
+        },
+        {
+            code: [
+                "import { Foo } from 'foo'",
+                "const bar = function <T>() {}",
+                "bar<Foo>()"
+            ].join("\n"),
+            parser
+        },
+        {
+            code: [
+                "import { Foo } from 'foo'",
+                "const bar = <T>() => {}",
+                "bar<Foo>()"
+            ].join("\n"),
+            parser
+        },
+        {
+            code: ["import { Foo } from 'foo'", "<Foo>(<T>() => {})()"].join(
+                "\n"
+            ),
+            parser
+        },
         {
             code: [
                 "import { Nullable } from 'nullable'",
@@ -469,6 +499,21 @@ ruleTester.run("no-unused-vars", ruleNoUnusedVars, {
                 }
             ]
         },
+        {
+            code: [
+                "import { Foo, Bar } from 'foo';",
+                "function baz<Foo>() {}",
+                "baz<Bar>()"
+            ].join("\n"),
+            parser,
+            errors: [
+                {
+                    message: "'Foo' is defined but never used.",
+                    line: 1,
+                    column: 10
+                }
+            ]
+        },
         {
             code: [
                 "import { Nullable } from 'nullable';",