This PR complains that the -Wpedantic -Werror=write-strings combination doesn't
result in an error but in a pedwarn, which I think is a valid point. The
principle is that more specific options take precedence over less specific
options, so e.g. -Wpedantic -Wno-write-strings shouldn't give a -Wwrite-strings
warning. -Wwrite-strings is enabled by default for C++:
c-family/c-opts.c:205: opts->x_warn_write_strings = c_dialect_cxx ();
so I think the following patch fixes the problem; the warning will only ever be
disabled if the user specifies -Wno-write-strings, and in C++11 it will always
be a pedwarn, so -pedantic-errors works as expected. I added a bunch of tests
to further exercise other combinations, too.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2017-03-02 Marek Polacek <pola...@redhat.com>
PR c++/79791
* typeck.c (string_conv_p): In C++11, always call pedwarn with
OPT_Wwrite_strings.
* g++.dg/warn/Wwrite-strings-1.C: New test.
* g++.dg/warn/Wwrite-strings-2.C: New test.
* g++.dg/warn/Wwrite-strings-3.C: New test.
* g++.dg/warn/Wwrite-strings-4.C: New test.
* g++.dg/warn/Wwrite-strings-5.C: New test.
* g++.dg/warn/Wwrite-strings-6.C: New test.
* g++.dg/warn/Wwrite-strings-7.C: New test.
* g++.dg/warn/Wwrite-strings-8.C: New test.
* g++.dg/warn/Wwrite-strings-9.C: New test.
* g++.dg/warn/Wwrite-strings-10.C: New test.
* g++.dg/warn/Wwrite-strings-11.C: New test.
* g++.dg/warn/Wwrite-strings-12.C: New test.
diff --git gcc/cp/typeck.c gcc/cp/typeck.c
index 3216bc41..d111124 100644
--- gcc/cp/typeck.c
+++ gcc/cp/typeck.c
@@ -2175,8 +2175,7 @@ string_conv_p (const_tree totype, const_tree exp, int
warn)
if (warn)
{
if (cxx_dialect >= cxx11)
- pedwarn (input_location,
- pedantic ? OPT_Wpedantic : OPT_Wwrite_strings,
+ pedwarn (input_location, OPT_Wwrite_strings,
"ISO C++ forbids converting a string constant to %qT",
totype);
else
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-1.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-1.C
index e69de29..05abca3 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-1.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-1.C
@@ -0,0 +1,5 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+char *s = "foo"; // { dg-warning "ISO C\\+\\+ forbids converting a string
constant" }
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-10.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-10.C
index e69de29..d34b0b0 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-10.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-10.C
@@ -0,0 +1,5 @@
+// PR c++/79791
+// { dg-do compile { target { ! c++11 } } }
+// { dg-options "" }
+
+char *s = "foo"; // { dg-warning "deprecated conversion from string constant" }
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-11.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-11.C
index e69de29..11ddcdb 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-11.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-11.C
@@ -0,0 +1,5 @@
+// PR c++/79791
+// { dg-do compile { target { ! c++11 } } }
+// { dg-options "-pedantic-errors" }
+
+char *s = "foo"; // { dg-warning "deprecated conversion from string constant" }
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-12.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-12.C
index e69de29..754a9c8 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-12.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-12.C
@@ -0,0 +1,6 @@
+// PR c++/79791
+// { dg-do compile { target { ! c++11 } } }
+// { dg-options "-Werror=write-strings" }
+// { dg-message "some warnings being treated as errors" "" { target *-*-* } 0 }
+
+char *s = "foo"; // { dg-error "deprecated conversion from string constant" }
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-2.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-2.C
index e69de29..53084d9 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-2.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-2.C
@@ -0,0 +1,5 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "-pedantic-errors" }
+
+char *s = "foo"; // { dg-error "ISO C\\+\\+ forbids converting a string
constant" }
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-3.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-3.C
index e69de29..6cb9654 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-3.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-3.C
@@ -0,0 +1,5 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "-pedantic-errors -Wno-write-strings" }
+
+char *s = "foo";
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-4.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-4.C
index e69de29..2654c39 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-4.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-4.C
@@ -0,0 +1,6 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "-Werror=write-strings" }
+// { dg-message "some warnings being treated as errors" "" { target *-*-* } 0 }
+
+char *s = "foo"; // { dg-error "ISO C\\+\\+ forbids converting a string
constant" }
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-5.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-5.C
index e69de29..f58ea90 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-5.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-5.C
@@ -0,0 +1,6 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "-Werror=write-strings -Wpedantic" }
+// { dg-message "some warnings being treated as errors" "" { target *-*-* } 0 }
+
+char *s = "foo"; // { dg-error "ISO C\\+\\+ forbids converting a string
constant" }
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-6.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-6.C
index e69de29..ff89f38 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-6.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-6.C
@@ -0,0 +1,6 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "-Werror=write-strings -Wno-pedantic" }
+// { dg-message "some warnings being treated as errors" "" { target *-*-* } 0 }
+
+char *s = "foo"; // { dg-error "ISO C\\+\\+ forbids converting a string
constant" }
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-7.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-7.C
index e69de29..13a8291 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-7.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-7.C
@@ -0,0 +1,5 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wno-write-strings" }
+
+char *s = "foo";
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-8.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-8.C
index e69de29..df5f283 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-8.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-8.C
@@ -0,0 +1,5 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wpedantic -Wno-write-strings" }
+
+char *s = "foo";
diff --git gcc/testsuite/g++.dg/warn/Wwrite-strings-9.C
gcc/testsuite/g++.dg/warn/Wwrite-strings-9.C
index e69de29..5db813b 100644
--- gcc/testsuite/g++.dg/warn/Wwrite-strings-9.C
+++ gcc/testsuite/g++.dg/warn/Wwrite-strings-9.C
@@ -0,0 +1,5 @@
+// PR c++/79791
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wno-error=write-strings -pedantic-errors" }
+
+char *s = "foo"; // { dg-warning "ISO C\\+\\+ forbids converting a string
constant" }
Marek
