Lex: Require that '#' be followed by a macro parameter name when preceded by '##'
After lexing a '##', we would look ahead and check to see if it was
followed by '__VA_ARGS__'. After doing so, we would then go ahead and
lex the token.
However we would fail in the case where the '##' was followed by a '#'
followed by an identifier because we would have lexed the '#' separately
from the identifier, bypassing our parameter validation logic.
Instead, lex the tokens coming after the '##' later.
This fixes PR17804.
llvm-svn: 194059
diff --git a/clang/test/Preprocessor/macro_paste_bad.c b/clang/test/Preprocessor/macro_paste_bad.c
index 0a028a4..2114654 100644
--- a/clang/test/Preprocessor/macro_paste_bad.c
+++ b/clang/test/Preprocessor/macro_paste_bad.c
@@ -32,3 +32,5 @@
#define VA __VA_ ## ARGS__
int VA; // expected-warning {{__VA_ARGS__ can only appear in the expansion of a C99 variadic macro}}
+#define LOG_ON_ERROR(lvl) ::X x## #__LINE__; // expected-error {{'#' is not followed by a macro parameter}}
+LOG_ON_ERROR(0);