PR10101: Recover better from a common copy-paste error: if a function

declaration at namespace scope is followed by a semicolon and an open-brace
(or in C++, a 'try', ':' or '='), then the error is probably a function
definition with a spurious ';', rather than a mysterious '{'.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@145372 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 1 deletions

diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 3bddd3de13..75c423340c 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -1041,13 +1041,28 @@ Parser::DeclGroupPtrTy Parser::ParseDeclGroup(ParsingDeclSpec &DS,
     return DeclGroupPtrTy();
   }
 
+  // Do we have a stray semicolon in the middle of a function definition?
+  if (AllowFunctionDefinitions && D.isFunctionDeclarator() &&
+      Tok.is(tok::semi) && Context == Declarator::FileContext) {
+    const Token &Next = NextToken();
+    if (Next.is(tok::l_brace) || Next.is(tok::kw_try) ||
+        (getLang().CPlusPlus &&
+         (Next.is(tok::colon) || Next.is(tok::equal)))) {
+      // Pretend we didn't see the semicolon.
+      SourceLocation SemiLoc = ConsumeToken();
+      Diag(SemiLoc, diag::err_stray_semi_function_definition)
+        << FixItHint::CreateRemoval(SemiLoc);
+      assert(isStartOfFunctionDefinition(D) && "expected a function defn");
+    }
+  }
+
   // Check to see if we have a function *definition* which must have a body.
   if (AllowFunctionDefinitions && D.isFunctionDeclarator() &&
       // Look at the next token to make sure that this isn't a function
       // declaration.  We have to check this because __attribute__ might be the
       // start of a function definition in GCC-extended K&R C.
       !isDeclarationAfterDeclarator()) {
-    
+
     if (isStartOfFunctionDefinition(D)) {
       if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
         Diag(Tok, diag::err_function_declared_typedef);