https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85425
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The example can be reduced to:
void ghhrobust_search (double ay, int type) { }
void f(int i, double d) { ghhrobust_search(i, d); }
This must not produce an error, because it is 100% valid according to the C
standard. An int can be converted to a double and a double can be converted to
an int, so the code is valid.
If you use -Wconversion you get a warning:
a.c: In function ‘void f(int, double)’:
a.c:3:48: warning: conversion to ‘int’ from ‘double’ may alter its value
[-Wfloat-conversion]
void f(int i, double d) { ghhrobust_search(i, d); }
^
This seems to be what you're looking for. Indeed, compiling your attached code
with -Wconversion gives a warning on the relevant line:
fail_contour.c: In function ‘contour_trace’:
fail_contour.c:203:56: warning: conversion to ‘int’ from ‘double’ may alter its
value [-Wfloat-conversion]
