clang-format: [JS] support cast syntax and type arguments.

Casts in TS syntax (foo = <type>bar;) should not be followed by
whitespace.

Patch by Martin Probst. Thank you.

llvm-svn: 232321
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index c6c81a48..911d52d 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1779,6 +1779,13 @@
     if ((Left.is(tok::l_brace) || Right.is(tok::r_brace)) &&
         Line.First->isOneOf(Keywords.kw_import, tok::kw_export))
       return false;
+    if (Left.is(TT_TemplateCloser) &&
+        !Right.isOneOf(tok::l_brace, tok::comma, tok::l_square,
+                       Keywords.kw_implements, Keywords.kw_extends))
+      // Type assertions ('<type>expr') are not followed by whitespace. Other
+      // locations that should have whitespace following are identified by the
+      // above set of follower tokens.
+      return false;
   } else if (Style.Language == FormatStyle::LK_Java) {
     if (Left.is(tok::r_square) && Right.is(tok::l_brace))
       return true;
diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index 045b280..5707024 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -616,5 +616,17 @@
   verifyFormat("var x = `hello` == `hello`;");
 }
 
+TEST_F(FormatTestJS, CastSyntax) {
+  verifyFormat("var x = <type>foo;");
+}
+
+TEST_F(FormatTestJS, TypeArguments) {
+  verifyFormat("class X<Y> {}");
+  verifyFormat("new X<Y>();");
+  verifyFormat("foo<Y>(a);");
+  verifyFormat("var x: X<Y>[];");
+  verifyFormat("class C extends D<E> implements F<G>, H<I> {}");
+}
+
 } // end namespace tooling
 } // end namespace clang