njames93 added inline comments.
================
Comment at: clang-tools-extra/clang-tidy/bugprone/BranchCloneCheck.cpp:62
Finder->addMatcher(
- ifStmt(stmt().bind("if"),
+ ifStmt(unless(allOf(isConstexpr(), isInTemplateInstantiation())),
+ stmt().bind("if"),
----------------
xazax.hun wrote:
> njames93 wrote:
> > xazax.hun wrote:
> > > Why do we care if we are inside a template instantiation?
> > >
> > > Couldn't we trigger the bug with something like:
> > > ```
> > > void shouldPass() {
> > > if constexpr (constexprFun(1) == 0) {
> > > handle(0);
> > > } else if constexpr (constexprFun(1) == 1) {
> > > handle(1);
> > > } else {
> > > handle(2);
> > > }
> > > }
> > > ```
> > >
> > > ?
> > We are disabling the bug check when we are in a template instantiation.
> > Reason being the template instantiation folds away the false branches to
> > null statements which is the cause of the false positives. Also if there is
> > a bug in a templated if constexpr, it will be caught when the template is
> > defined.
> Yeah, be people are free to write `if constexpr` outside of templates right?
> So instantiations are not the only places where branches can be folded away.
The issue is that only template instantiations cause the false branch to get
folded away, observe [[ https://godbolt.org/z/u48xzy | here ]] to see how its
handled in templated code that isn't yet instantiated, instantiated template
code and normal untemplated code
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D71980/new/
https://reviews.llvm.org/D71980
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