clang-format: [JS] support fields with case/switch/default labels.

Summary:
`case:` and `default:` would normally parse as labels for a `switch` block.
However in TypeScript, they can be used in field declarations, e.g.:

    interface I {
      case: string;
    }

This change special cases parsing them in declaration lines to avoid wrapping
them.

Reviewers: djasper

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D36148

llvm-svn: 310070

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 32853dc209e..e6afd1f9887 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -326,6 +326,11 @@ void UnwrappedLineParser::parseLevel(bool HasOpeningBrace) {
       break;
     case tok::kw_default:
     case tok::kw_case:
+      if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration) {
+        // A 'case: string' style field declaration.
+        parseStructuralElement();
+        break;
+      }
       if (!SwitchLabelEncountered &&
           (Style.IndentCaseLabels || (Line->InPPDirective && Line->Level == 1)))
         ++Line->Level;
@@ -953,13 +958,22 @@ void UnwrappedLineParser::parseStructuralElement() {
     parseDoWhile();
     return;
   case tok::kw_switch:
+    if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
+      // 'switch: string' field declaration.
+      break;
     parseSwitch();
     return;
   case tok::kw_default:
+    if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
+      // 'default: string' field declaration.
+      break;
     nextToken();
     parseLabel();
     return;
   case tok::kw_case:
+    if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
+      // 'case: string' field declaration.
+      break;
     parseCaseLabel();
     return;
   case tok::kw_try: