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<div id="divRplyFwdMsg"><strong>From:</strong> Balázs Benics <balazs.benics@sigmatechnology.se><br>
<strong>Sent:</strong> Tuesday, November 23, 2021, 14:45<br>
<strong>To:</strong> cfe-dev<br>
<strong>Subject:</strong> Same AST for is_same<char, int="">::value and is_same<char, long="">::value<br>
</char,></char,></div>
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<p class="MsoNormal"><span lang="EN-US">I seek some advice on the following AST scenario.</span></p>
<p class="MsoNormal"><span lang="EN-US"><a href="https://godbolt.org/z/WcTeoGcbG" style="">https://godbolt.org/z/WcTeoGcbG</a></span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">1 #include <type_traits></span></p>
<p class="MsoNormal"><span lang="EN-US">2 using std::is_same;</span></p>
<p class="MsoNormal"><span lang="EN-US">3 bool top() {</span></p>
<p class="MsoNormal"><span lang="EN-US">4 return is_same<char, int>::value || is_same<char, long>::value;</span></p>
<p class="MsoNormal"><span lang="EN-US">5 }</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">The `alpha.core.IdenticalExpr` static analyzer checker warns about that the two `..::value` are identical DeclRefExprs.</span></p>
<p class="MsoNormal"><span lang="EN-US">According to the AST, they are indeed identical:</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US"> BinaryOperator <col:10, col:60> 'bool' '||'</span></p>
<p class="MsoNormal"><span lang="EN-US"> |-ImplicitCastExpr <col:10, col:30> 'bool':'bool' <LValueToRValue></span></p>
<p class="MsoNormal"><span lang="EN-US"> | `-DeclRefExpr <col:10, col:30> 'const bool':'const bool' lvalue Var 0x563b67cde0a8 'value' 'const bool':'const bool'</span></p>
<p class="MsoNormal"><span lang="EN-US"> `-ImplicitCastExpr <col:39, col:60> 'bool':'bool' <LValueToRValue></span></p>
<p class="MsoNormal"><span lang="EN-US"> `-DeclRefExpr <col:39, col:60> 'const bool':'const bool' lvalue Var 0x563b67cde0a8 'value' 'const bool':'const bool'</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">Both of them refers to the same `VarDecl`, corresponding (probably) to the `std::false_type::value`.</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">How can I detect that even though the `values` look similar, they correspond to different template instances in that sense?</span></p>
<p class="MsoNormal"><span lang="EN-US">What do you suggest?</span></p>
<p class="MsoNormal"><span lang="EN-US">In the end, I want to suppress these reports in the static analyzer.</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">Balázs</span></p>
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