[clang-format] Fix line parsing for noexcept lambdas

Summary:
> $ echo "int c = [b]() mutable noexcept { return [&b] { return b++; }(); }();" |clang-format

```
int c = [b]() mutable noexcept {
  return [&b] { return b++; }();
}
();
```
with patch:
> $ echo "int c = [b]() mutable noexcept { return [&b] { return b++; }(); }();" |bin/clang-format
```
int c = [b]() mutable noexcept { return [&b] { return b++; }(); }();
```

Contributed by hultman.

Reviewers: benhamilton, jolesiak, klimek, Wizard

Reviewed By: benhamilton

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D56909

llvm-svn: 352622

clang/lib/Format/UnwrappedLineParser.cpp

@@ -1422,6 +1422,7 @@ bool UnwrappedLineParser::tryToParseLambda() {
     case tok::numeric_constant:
     case tok::coloncolon:
     case tok::kw_mutable:
+    case tok::kw_noexcept:
       nextToken();
       break;
     case tok::arrow:

clang/unittests/Format/FormatTest.cpp

@@ -11725,6 +11725,8 @@ TEST_F(FormatTest, FormatsWithWebKitStyle) {
 
 TEST_F(FormatTest, FormatsLambdas) {
   verifyFormat("int c = [b]() mutable { return [&b] { return b++; }(); }();\n");
+  verifyFormat(
+      "int c = [b]() mutable noexcept { return [&b] { return b++; }(); }();\n");
   verifyFormat("int c = [&] { [=] { return b++; }(); }();\n");
   verifyFormat("int c = [&, &a, a] { [=, c, &d] { return b++; }(); }();\n");
   verifyFormat("int c = [&a, &a, a] { [=, a, b, &c] { return b++; }(); }();\n");