From f25d2de17663a0132f9fe090dee39d3b1132067b Mon Sep 17 00:00:00 2001
From: Marek Polacek <polacek@redhat.com>
Date: Tue, 16 May 2023 14:12:06 -0400
Subject: [PATCH] c++: -Wdangling-reference not suppressed in template
[PR109774]
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.
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 53ac925a0924..c225c4e24232 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 000000000000..bc09fbae22ba
--- /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;
+}
--
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