In the case of convert_argument, we would return the same expression back rather than error_mark_node after the error message about trying to convert to an incomplete type. This causes issues in the gimplfier trying to see if another conversion is needed.
The code here dates back to before the revision history too so it might be the case it never noticed we should return an error_mark_node. Bootstrapped and tested on x86_64-linux-gnu with no regressions. PR c/100532 gcc/c/ChangeLog: * c-typeck.cc (convert_argument): After erroring out about an incomplete type return error_mark_node. gcc/testsuite/ChangeLog: * gcc.dg/pr100532-1.c: New test. --- gcc/c/c-typeck.cc | 2 +- gcc/testsuite/gcc.dg/pr100532-1.c | 7 +++++++ 2 files changed, 8 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/pr100532-1.c diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc index 6e044b4afbc..8f8562936dc 100644 --- a/gcc/c/c-typeck.cc +++ b/gcc/c/c-typeck.cc @@ -3367,7 +3367,7 @@ convert_argument (location_t ploc, tree function, tree fundecl, { error_at (ploc, "type of formal parameter %d is incomplete", parmnum + 1); - return val; + return error_mark_node; } /* Optionally warn about conversions that differ from the default diff --git a/gcc/testsuite/gcc.dg/pr100532-1.c b/gcc/testsuite/gcc.dg/pr100532-1.c new file mode 100644 index 00000000000..81e37c60415 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr100532-1.c @@ -0,0 +1,7 @@ +/* { dg-do compile } */ +/* PR c/100532 */ + +typedef __SIZE_TYPE__ size_t; +void *memcpy(void[], const void *, size_t); /* { dg-error "declaration of type name" } */ +void c(void) { memcpy(c, "a", 2); } /* { dg-error "type of formal parameter" } */ + -- 2.34.1