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// RUN: %clang_cc1 -fsyntax-only -verify -Wtop-level-comparison -Wno-unused %s
struct A {
bool operator==(const A&);
bool operator!=(const A&);
A operator|=(const A&);
operator bool();
};
void test() {
int x, *p;
A a, b;
x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
x != 7; // expected-warning {{inequality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '|=' to turn this inequality comparison into an or-assignment}}
7 == x; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}}
p == p; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}} \
// expected-warning {{self-comparison always evaluates to true}}
a == a; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
a == b; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
a != b; // expected-warning {{inequality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '|=' to turn this inequality comparison into an or-assignment}}
A() == b; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}}
if (42) x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
else if (42) x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
else x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
do x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
while (false);
while (false) x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
for (x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
x == 7; // No warning -- result is used
x == 7) // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
switch (42) default: x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
switch (42) case 42: x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
switch (42) {
case 1:
case 2:
default:
case 3:
case 4:
x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
}
(void)(x == 7);
(void)(p == p); // expected-warning {{self-comparison always evaluates to true}}
{ bool b = x == 7; }
{ bool b = ({ x == 7; // expected-warning {{equality comparison as an unused top-level statement}} \
// expected-note {{cast this comparison to void to silence this warning}} \
// expected-note {{use '=' to turn this equality comparison into an assignment}}
x == 7; }); } // no warning on the second, its result is used!
#define EQ(x,y) (x) == (y)
EQ(x, 5);
#undef EQ
}
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