[gcc/devel/c++-modules] c++: Redundant -Wdeprecated-declarations warning in build_over_call [PR67960]

[gcc/devel/c++-modules] c++: Redundant -Wdeprecated-declarations warning in build_over_call [PR67960]

[Nathan Sidwell]

https://gcc.gnu.org/g:80a13af724aedfb360893dcc16aa7cc12ca49799

commit 80a13af724aedfb360893dcc16aa7cc12ca49799
Author: Patrick Palka <ppalka@redhat.com>
Date:   Thu Mar 12 14:38:42 2020 -0400

    c++: Redundant -Wdeprecated-declarations warning in build_over_call [PR67960]
    
    In build_over_call, we are emitting a redundant -Wdeprecated-declarations
    warning about the deprecated callee function, first from mark_used and again
    from build_addr_func <- decay_conversion <- cp_build_addr_expr <- mark_used.
    
    It seems this second deprecation warning coming from build_addr_func will always
    be redundant, so we can safely use a warning_sentinel to disable it before
    calling build_addr_func.  (And any deprecation warning that could come from
    build_addr_func would be for FN, so we wouldn't be suppressing too much.)
    
    gcc/cp/ChangeLog:
    
            PR c++/67960
            * call.c (build_over_call): Use a warning_sentinel to disable
            warn_deprecated_decl before calling build_addr_func.
    
    gcc/testsuite/ChangeLog:
    
            PR c++/67960
            * g++.dg/diagnostic/pr67960.C: New test.
            * g++.dg/diagnostic/pr67960-2.C: New test.

Diff:
---
 gcc/cp/ChangeLog                            |  6 ++++++
 gcc/cp/call.c                               |  5 +++++
 gcc/testsuite/ChangeLog                     |  6 ++++++
 gcc/testsuite/g++.dg/diagnostic/pr67960-2.C | 13 +++++++++++++
 gcc/testsuite/g++.dg/diagnostic/pr67960.C   | 13 +++++++++++++
 5 files changed, 43 insertions(+)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index b94e3bb8eb2..eea795de218 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-13  Patrick Palka  <ppalka@redhat.com>
+
+	PR c++/67960
+	* call.c (build_over_call): Use a warning_sentinel to disable
+	warn_deprecated_decl before calling build_addr_func.
+
 2020-03-12  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/94124
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 5767a8b8c4e..1715acc0ec3 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -9062,6 +9062,11 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
     }
   else
     {
+      /* If FN is marked deprecated, then we've already issued a deprecated-use
+	 warning from mark_used above, so avoid redundantly issuing another one
+	 from build_addr_func.  */
+      warning_sentinel w (warn_deprecated_decl);
+
       fn = build_addr_func (fn, complain);
       if (fn == error_mark_node)
 	return error_mark_node;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6e2099bec5a..2f738fadd80 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-13  Patrick Palka  <ppalka@redhat.com>
+
+	PR c++/67960
+	* g++.dg/diagnostic/pr67960.C: New test.
+	* g++.dg/diagnostic/pr67960-2.C: New test.
+
 2020-03-13  Martin Liska  <mliska@suse.cz>
 
 	PR lto/94157
diff --git a/gcc/testsuite/g++.dg/diagnostic/pr67960-2.C b/gcc/testsuite/g++.dg/diagnostic/pr67960-2.C
new file mode 100644
index 00000000000..d2ba509534f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/pr67960-2.C
@@ -0,0 +1,13 @@
+// PR c++/67960
+// { dg-do compile }
+// { dg-additional-options "-Werror -fmax-errors=1" }
+__attribute__((deprecated)) void doNothing(){}
+
+int
+main()
+{
+  doNothing(); // { dg-error "is deprecated" }
+}
+
+// { dg-message "all warnings being treated as errors" "" { target *-*-* } 0 }
+// { dg-bogus "compilation terminated" "" { target *-*-* } 0 }
diff --git a/gcc/testsuite/g++.dg/diagnostic/pr67960.C b/gcc/testsuite/g++.dg/diagnostic/pr67960.C
new file mode 100644
index 00000000000..d7b1a2d0811
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/pr67960.C
@@ -0,0 +1,13 @@
+// PR c++/67960
+// { dg-do compile { target c++14 } }
+// { dg-additional-options "-Werror -fmax-errors=1" }
+[[deprecated]] void doNothing(){}
+
+int
+main()
+{
+  doNothing(); // { dg-error "is deprecated" }
+}
+
+// { dg-message "all warnings being treated as errors" "" { target *-*-* } 0 }
+// { dg-bogus "compilation terminated" "" { target *-*-* } 0 }