| Message ID | 20230516191354.155428-1-polacek@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: -Wdangling-reference not suppressed in template [PR109774] | expand |
On 5/16/23 15:13, Marek Polacek wrote: > In check_return_expr, we suppress the -Wdangling-reference warning when > we're sure it would be a false positive. It wasn't working in a > template, though, because the suppress_warning call was never reached. > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk and 13.2? OK. > PR c++/109774 > > gcc/cp/ChangeLog: > > * typeck.cc (check_return_expr): In a template, return only after > suppressing -Wdangling-reference. > > gcc/testsuite/ChangeLog: > > * g++.dg/warn/Wdangling-reference13.C: New test. > --- > gcc/cp/typeck.cc | 6 ++--- > .../g++.dg/warn/Wdangling-reference13.C | 23 +++++++++++++++++++ > 2 files changed, 26 insertions(+), 3 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/warn/Wdangling-reference13.C > > diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc > index 53ac925a092..c225c4e2423 100644 > --- a/gcc/cp/typeck.cc > +++ b/gcc/cp/typeck.cc > @@ -11236,9 +11236,6 @@ check_return_expr (tree retval, bool *no_warning) > build_zero_cst (TREE_TYPE (retval))); > } > > - if (processing_template_decl) > - return saved_retval; > - > /* A naive attempt to reduce the number of -Wdangling-reference false > positives: if we know that this function can return a variable with > static storage duration rather than one of its parameters, suppress > @@ -11250,6 +11247,9 @@ check_return_expr (tree retval, bool *no_warning) > && TREE_STATIC (bare_retval)) > suppress_warning (current_function_decl, OPT_Wdangling_reference); > > + if (processing_template_decl) > + return saved_retval; > + > /* Actually copy the value returned into the appropriate location. */ > if (retval && retval != result) > { > diff --git a/gcc/testsuite/g++.dg/warn/Wdangling-reference13.C b/gcc/testsuite/g++.dg/warn/Wdangling-reference13.C > new file mode 100644 > index 00000000000..bc09fbae22b > --- /dev/null > +++ b/gcc/testsuite/g++.dg/warn/Wdangling-reference13.C > @@ -0,0 +1,23 @@ > +// PR c++/109774 > +// { dg-do compile } > +// { dg-options "-Wdangling-reference" } > + > +int y; > + > +template<typename T> > +int& get(const char& ) > +{ > + return y; > +} > + > +int& get2(const char&) > +{ > + return y; > +} > + > +int stuff(void) > +{ > + const int &h = get<void>(0); // { dg-bogus "dangling reference" } > + const int &k = get2(0); // { dg-bogus "dangling reference" } > + return h+k; > +} > > base-commit: 94a311abf783de754f0f1b2d4c1f00a9788e795b
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc index 53ac925a092..c225c4e2423 100644 --- a/gcc/cp/typeck.cc +++ b/gcc/cp/typeck.cc @@ -11236,9 +11236,6 @@ check_return_expr (tree retval, bool *no_warning) build_zero_cst (TREE_TYPE (retval))); } - if (processing_template_decl) - return saved_retval; - /* A naive attempt to reduce the number of -Wdangling-reference false positives: if we know that this function can return a variable with static storage duration rather than one of its parameters, suppress @@ -11250,6 +11247,9 @@ check_return_expr (tree retval, bool *no_warning) && TREE_STATIC (bare_retval)) suppress_warning (current_function_decl, OPT_Wdangling_reference); + if (processing_template_decl) + return saved_retval; + /* Actually copy the value returned into the appropriate location. */ if (retval && retval != result) { diff --git a/gcc/testsuite/g++.dg/warn/Wdangling-reference13.C b/gcc/testsuite/g++.dg/warn/Wdangling-reference13.C new file mode 100644 index 00000000000..bc09fbae22b --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Wdangling-reference13.C @@ -0,0 +1,23 @@ +// PR c++/109774 +// { dg-do compile } +// { dg-options "-Wdangling-reference" } + +int y; + +template<typename T> +int& get(const char& ) +{ + return y; +} + +int& get2(const char&) +{ + return y; +} + +int stuff(void) +{ + const int &h = get<void>(0); // { dg-bogus "dangling reference" } + const int &k = get2(0); // { dg-bogus "dangling reference" } + return h+k; +}