When we see 'Class(X' or 'Class::Class(X' and we suspect that it names a

constructor, but X is not a known typename, check whether the tokens could
possibly match the syntax of a declarator before concluding that it isn't
a constructor. If it's definitely ill-formed, assume it is a constructor.

Empirical evidence suggests that this pattern is much more often a
constructor with a typoed (or not-yet-declared) type name than any of the
other possibilities, so the extra cost of the check is not expected to be
problematic.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153488 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 1 deletions

diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 24386d08ba..75abcae282 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -3379,7 +3379,42 @@ bool Parser::isConstructorDeclarator() {
   // Check whether the next token(s) are part of a declaration
   // specifier, in which case we have the start of a parameter and,
   // therefore, we know that this is a constructor.
-  bool IsConstructor = isDeclarationSpecifier();
+  bool IsConstructor = false;
+  if (isDeclarationSpecifier())
+    IsConstructor = true;
+  else if (Tok.is(tok::identifier) ||
+           (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::identifier))) {
+    // We've seen "C ( X" or "C ( X::Y", but "X" / "X::Y" is not a type.
+    // This might be a parenthesized member name, but is more likely to
+    // be a constructor declaration with an invalid argument type. Keep
+    // looking.
+    if (Tok.is(tok::annot_cxxscope))
+      ConsumeToken();
+    ConsumeToken();
+
+    // If this is not a constructor, we must be parsing a declarator,
+    // which must have one of the following syntactic forms:
+    switch (Tok.getKind()) {
+    case tok::l_paren:
+      // C(X   (   int));
+    case tok::l_square:
+      // C(X   [   5]);
+      // C(X   [   [attribute]]);
+    case tok::coloncolon:
+      // C(X   ::   Y);
+      // C(X   ::   *p);
+    case tok::r_paren:
+      // C(X   )
+      // Assume this isn't a constructor, rather than assuming it's a
+      // constructor with an unnamed parameter of an ill-formed type.
+      break;
+
+    default:
+      IsConstructor = true;
+      break;
+    }
+  }
+
   TPA.Revert();
   return IsConstructor;
 }