typescript: remove unneeded parentheses around type annotation (#5724)

* Remove unnecessary parentheses from annotations

* add test for ts parentheses bug

src/language-js/needs-parens.js

@@ -339,7 +339,6 @@ function needsParens(path, options) {
           parent.type === "GenericTypeAnnotation" ||
           parent.type === "TSTypeReference") &&
         (node.typeAnnotation.type === "TSTypeAnnotation" &&
-          node.typeAnnotation.typeAnnotation.type !== "TSFunctionType" &&
           grandParent.type !== "TSTypeOperator" &&
           grandParent.type !== "TSOptionalType")
       ) {

tests/typescript/conformance/types/functions/TSFunctionTypeNoUnnecessaryParentheses.ts

@@ -0,0 +1,3 @@
+class Foo {
+  bar: (() => boolean);
+}

tests/typescript/conformance/types/functions/__snapshots__/jsfmt.spec.js.snap

@@ -1,5 +1,22 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`TSFunctionTypeNoUnnecessaryParentheses.ts 1`] = `
+====================================options=====================================
+parsers: ["typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+class Foo {
+  bar: (() => boolean);
+}
+=====================================output=====================================
+class Foo {
+  bar: () => boolean;
+}
+
+================================================================================
+`;
+
 exports[`functionImplementationErrors.ts 1`] = `
 ====================================options=====================================
 parsers: ["typescript"]