clang-format: [JS] avoid indent after ambient function declarations.

[mprobst]

Summary

Before:

declare function foo();
  let x = 1;

After:

declare function foo();
let x = 1;

The problem was that clang-format would unconditionally try to parse a child block, even though ambient function declarations do not have a body (similar to forward declarations).

[mprobst]

• Handle type declarations.

[sammccall]

unittests/Format/FormatTestJS.cpp

382 ↗

(On Diff #83028)

Maybe include an inline object return type for completeness?

[mprobst]

• Handle type declarations.
• test for object literal return types

[mprobst]

unittests/Format/FormatTestJS.cpp

382 ↗

(On Diff #83028)

Done. There are still a lot of corner cases (e.g. union type with curlies in a latter type). We'd need to parse more or less the entire type grammar for that though :-/

cfe/trunk/lib/Format/UnwrappedLineParser.cpp

if (FormatTok->is(tok::colon)) {
     // Parse a type definition.
     nextToken();
 
     // Eat the type declaration. For braced inline object types, balance braces,
     // otherwise just parse until finding an l_brace for the function body.
     if (FormatTok->is(tok::l_brace))
       tryToParseBracedList();
     else
-      while (FormatTok->isNot(tok::l_brace) && !eof())
+      while (!FormatTok->isOneOf(tok::l_brace, tok::semi) && !eof())
         nextToken();
   }
 
+  if (FormatTok->is(tok::semi))
+    return;
+
   parseChildBlock();
 }
 
 bool UnwrappedLineParser::tryToParseBracedList() {
   if (FormatTok->BlockKind == BK_Unknown)
     calculateBraceTypes();
   assert(FormatTok->BlockKind != BK_Unknown);
   if (FormatTok->BlockKind == BK_Block)

cfe/trunk/unittests/Format/FormatTestJS.cpp

TEST_F(FormatTestJS, AmbientDeclarations) {
   verifyFormat(
       "declare class\n"
       "    X {}",
       NineCols);
   verifyFormat(
       "declare function\n"
       "x();",  // TODO(martinprobst): should ideally be indented.
       NineCols);
+  verifyFormat("declare function foo();\n"
+               "let x = 1;\n");
+  verifyFormat("declare function foo(): string;\n"
+               "let x = 1;\n");
+  verifyFormat("declare function foo(): {x: number};\n"
+               "let x = 1;\n");
+  verifyFormat("declare class X {}\n"
+               "let x = 1;\n");
+  verifyFormat("declare interface Y {}\n"
+               "let x = 1;\n");
   verifyFormat(
       "declare enum X {\n"
       "}",
       NineCols);
   verifyFormat(
       "declare let\n"
       "    x: number;",
       NineCols);