[Bug c/105362] New: Improvement: diagnose undefined behavior in preprocessing directives

[pavel.morozkin at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105362

            Bug ID: 105362
           Summary: Improvement: diagnose undefined behavior in
                    preprocessing directives
           Product: gcc
           Version: 11.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pavel.morozkin at gmail dot com
  Target Milestone: ---

#if 1 << -1
#endif

$ gcc -std=c11 -pedantic -Wall -Wextra -O3 -c

Expected diagnostics:
warning: left shift count is negative [-Wshift-count-negative]

Actual diagnostics:
<nothing>