Index: lib/Format/UnwrappedLineParser.cpp
===================================================================
--- lib/Format/UnwrappedLineParser.cpp
+++ lib/Format/UnwrappedLineParser.cpp
@@ -1255,10 +1255,13 @@
     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();
 }
 
Index: unittests/Format/FormatTestJS.cpp
===================================================================
--- unittests/Format/FormatTestJS.cpp
+++ unittests/Format/FormatTestJS.cpp
@@ -377,6 +377,14 @@
       "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 class X {}\n"
+               "let x = 1;\n");
+  verifyFormat("declare interface Y {}\n"
+               "let x = 1;\n");
   verifyFormat(
       "declare enum X {\n"
       "}",