fix(eslint-plugin): [no-unnec-type-arg] throwing on call/new expr (#1217)

a-tarasyuk · bradzacher · bradzacher · commit 42a48de4b5e3 · 2019-11-17T11:24:31.000-08:00
Co-authored-by: Brad Zacher &lt;brad.zacher@gmail.com&gt;
diff --git a/packages/eslint-plugin/src/rules/no-unnecessary-type-arguments.ts b/packages/eslint-plugin/src/rules/no-unnecessary-type-arguments.ts
@@ -114,7 +114,11 @@ function getTypeParametersFromNode(
     return getTypeParametersFromType(node.typeName, checker);
   }
 
-  return getTypeParametersFromCall(node, checker);
+  if (ts.isCallExpression(node) || ts.isNewExpression(node)) {
+    return getTypeParametersFromCall(node, checker);
+  }
+
+  return undefined;
 }
 
 function getTypeParametersFromType(
diff --git a/packages/eslint-plugin/tests/rules/no-unnecessary-type-arguments.test.ts b/packages/eslint-plugin/tests/rules/no-unnecessary-type-arguments.test.ts
@@ -53,6 +53,9 @@ ruleTester.run('no-unnecessary-type-arguments', rule, {
     `declare const C: unknown;
       class D<TD = number> extends C { }`,
     `let a: A<number>`,
+    `class Foo<T> {}
+      const foo = new Foo<number>();`,
+    `type Foo<T> = import('foo').Foo<T>;`,
   ],
   invalid: [
     {
@@ -123,5 +126,16 @@ ruleTester.run('no-unnecessary-type-arguments', rule, {
       output: `interface I<T = number> { }
         class Impl implements I { }`,
     },
+    {
+      code: `class Foo<T = number> {}
+        const foo = new Foo<number>();`,
+      errors: [
+        {
+          messageId: 'unnecessaryTypeParameter',
+        },
+      ],
+      output: `class Foo<T = number> {}
+        const foo = new Foo();`,
+    },
   ],
 });

Original file line number	Diff line number	Diff line change
`@@ -114,7 +114,11 @@ function getTypeParametersFromNode(`
`114`	`114`	`return getTypeParametersFromType(node.typeName, checker);`
`115`	`115`	`}`
`116`	`116`
`117`		`- return getTypeParametersFromCall(node, checker);`
	`117`	`+ if (ts.isCallExpression(node) \|\| ts.isNewExpression(node)) {`
	`118`	`+ return getTypeParametersFromCall(node, checker);`
	`119`	`+ }`
	`120`	`+`
	`121`	`+ return undefined;`
`118`	`122`	`}`
`119`	`123`
`120`	`124`	`function getTypeParametersFromType(`