clang/test/SemaTemplate/self-comparison.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %s
   2
   3 template <int A, int B> void foo() {
   4   (void)(A == A); // expected-warning {{self-comparison always evaluates to true}}
   5   (void)(A == B);
   6 }
   7 template <int A, int B> struct S1 {
   8   void foo() {
   9     (void)(A == A); // expected-warning {{self-comparison always evaluates to true}}
  10     (void)(A == B);
  11   }
  12 };
  13
  14 template <int A, int B> struct S2 {
  15   template <typename T> T foo() {
  16     (void)(A == A); // expected-warning {{self-comparison always evaluates to true}}
  17     (void)(A == B);
  18   }
  19 };
  20
  21 struct S3 {
  22   template <int A, int B> void foo() {
  23     (void)(A == A); // expected-warning {{self-comparison always evaluates to true}}
  24     (void)(A == B);
  25   }
  26 };
  27
  28 template <int A> struct S4 {
  29   template <int B> void foo() {
  30     (void)(A == A); // expected-warning {{self-comparison always evaluates to true}}
  31     (void)(A == B);
  32   }
  33 };
  34
  35 const int N = 42;
  36 template <int X> void foo2() {
  37   (void)(X == N);
  38   (void)(N == X);
  39 }
  40
  41 void test() {
  42   foo<1, 1>();
  43   S1<1, 1> s1; s1.foo();
  44   S2<1, 1> s2; s2.foo<void>();
  45   S3 s3; s3.foo<1, 1>();
  46   S4<1> s4; s4.foo<1>();
  47   foo2<N>();
  48 }