https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92212
Bug ID: 92212 Summary: incompatible calls to K&R functions not diagnosed Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: msebor at gcc dot gnu.org Target Milestone: --- Unlike some other compilers GCC doesn't diagnose incompatible calls to K&R style functions in the same translation unit. $ cat b.c && gcc -O2 -S -Wall -Wextra -Wpedantic b.c int f (i) int i; { return i; } int g (void) { return f (""); // missing warning } Both Clang and ICC detect the problem and issue the equivalent of: warning: incompatible pointer to integer conversion passing 'char [1]' to parameter of type 'int' [-Wint-conversion] return f (""); ^~