rsmith added inline comments.
================ Comment at: lib/Parse/ParseExprCXX.cpp:2906-2912 + // Basic lookahead to check if we have a lambda expression. If we + // encounter two braces with a semicolon, we can be pretty sure + // that this is a lambda, not say a compound literal. + if (!SkipUntil(tok::l_brace, SkipUntilFlags::StopAtSemi) || + (NextToken().isNot(tok::r_brace) && !SkipUntil(tok::semi)) || + !SkipUntil(tok::r_brace, SkipUntilFlags::StopAtSemi)) { + TPA.Revert(); ---------------- This seems error-prone. Given: ``` for (item *p = first, *oldp = p; p; p = p->next, delete [] oldp, oldp = p) { /*...*/; } ``` ... we'll decide the //delete-expression// is followed by a lambda. Likewise for cases like: ``` delete [] f->getPtr([] { return blah; }); ``` Our goal here should be a fast heuristic (don't use lookahead except when you're already confident you have a lambda) and zero false positives. How about these heuristics instead: Assume that the `delete []` is actually `delete` followed by a lambda if either: * The next token is `{` or `<`, or * The next token is `(` and either * the following token is `)` or * the following tokens are a type specifier followed by an identifier This should have no false positives, and only has false negatives if a lambda has an unnamed parameter or a parameter with a non-trivial parameter type. (For the last condition, we could try to tentatively parse an entire parameter and see if it has a name, which would handle all cases except an expression/declaration ambiguity in the parameter declaration, but that seems like overkill to me. This is already performing more lookahead than I'd like, but `delete []` expressions are rare enough that using two lookahead tokens for an improved error message seems OK.) https://reviews.llvm.org/D36357 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits