e0cee6a8b0
int x = 42; x = x; // Warns here. The warning avoids macro expansions, templates, user-defined assignment operators, and volatile types, so false positives are expected to be low. The common (mis-)use of this code pattern is to silence unused variable warnings, but a more idiomatic way of doing that is '(void)x;'. A follow-up to this will add a note and fix-it hint suggesting this replacement in cases where the StmtExpr consists precisely of the self assignment. llvm-svn: 122804
48 lines
922 B
C++
48 lines
922 B
C++
// RUN: %clang_cc1 -fsyntax-only -Wself-assign -verify %s
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void f() {
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int a = 42, b = 42;
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a = a; // expected-warning{{explicitly assigning}}
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b = b; // expected-warning{{explicitly assigning}}
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a = b;
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b = a = b;
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a = a = a; // expected-warning{{explicitly assigning}}
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a = b = b = a;
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}
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// Dummy type.
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struct S {};
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void false_positives() {
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#define OP =
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#define LHS a
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#define RHS a
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int a = 42;
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// These shouldn't warn due to the use of the preprocessor.
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a OP a;
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LHS = a;
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a = RHS;
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LHS OP RHS;
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#undef OP
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#undef LHS
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#undef RHS
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S s;
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s = s; // Not a builtin assignment operator, no warning.
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// Volatile stores aren't side-effect free.
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volatile int vol_a;
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vol_a = vol_a;
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volatile int &vol_a_ref = vol_a;
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vol_a_ref = vol_a_ref;
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}
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template <typename T> void g() {
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T a;
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a = a; // May or may not be a builtin assignment operator, no warning.
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}
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void instantiate() {
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g<int>();
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g<S>();
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}
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