clang/test/SemaCXX/constant-conversion.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-apple-darwin %s
   2
   3 // This file tests -Wconstant-conversion, a subcategory of -Wconversion
   4 // which is on by default.
   5
   6 constexpr int nines() { return 99999; }
   7
   8 void too_big_for_char(int param) {
   9   char warn1 = false ? 0 : 99999;
  10   // expected-warning@-1 {{implicit conversion from 'int' to 'char' changes value from 99999 to -97}}
  11   char warn2 = false ? 0 : nines();
  12   // expected-warning@-1 {{implicit conversion from 'int' to 'char' changes value from 99999 to -97}}
  13
  14   char warn3 = param > 0 ? 0 : 99999;
  15   // expected-warning@-1 {{implicit conversion from 'int' to 'char' changes value from 99999 to -97}}
  16   char warn4 = param > 0 ? 0 : nines();
  17   // expected-warning@-1 {{implicit conversion from 'int' to 'char' changes value from 99999 to -97}}
  18
  19   char ok1 = true ? 0 : 99999;
  20   char ok2 = true ? 0 : nines();
  21
  22   char ok3 = true ? 0 : 99999 + 1;
  23   char ok4 = true ? 0 : nines() + 1;
  24 }
  25
  26 void test_bitfield() {
  27   struct S {
  28     int one_bit : 1;
  29   } s;
  30
  31   s.one_bit = 1;    // expected-warning {{implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1}}
  32   s.one_bit = true; // no-warning
  33 }