[gcc r14-10887] c++: allow array mem-init with -fpermissive [PR116634]

[Jason Merrill via Gcc-cvs]

https://gcc.gnu.org/g:ce25ca4da198ebc269d41ee6a9ac880ae8f67ad6

commit r14-10887-gce25ca4da198ebc269d41ee6a9ac880ae8f67ad6
Author: Jason Merrill <ja...@redhat.com>
Date:   Mon Nov 4 17:48:46 2024 -0500

    c++: allow array mem-init with -fpermissive [PR116634]
    
    We've accidentally accepted this forever (at least as far back as 4.7), but
    it's always been ill-formed; this was PR59465.  And we didn't accept it for
    scalar types.  But rather than switch to a hard error for this code, let's
    give a permerror so affected code can continue to work with -fpermissive.
    
            PR c++/116634
    
    gcc/cp/ChangeLog:
    
            * init.cc (can_init_array_with_p): Allow PR59465 case with
            permerror.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/diagnostic/aggr-init1.C: Expect warning with -fpermissive.
            * g++.dg/init/array62.C: Adjust diagnostic.
            * g++.dg/init/array63.C: Adjust diagnostic.
            * g++.dg/init/array64.C: Adjust diagnostic.
    
    (cherry picked from commit 3545aab00152ed3db1d7ce6ca4e1671dde276980)

Diff:
---
 gcc/cp/init.cc                               |  4 ++-
 gcc/testsuite/g++.dg/diagnostic/aggr-init1.C | 37 ++++++++++++++++++++++++++++
 gcc/testsuite/g++.dg/init/array62.C          |  2 +-
 gcc/testsuite/g++.dg/init/array63.C          |  2 +-
 gcc/testsuite/g++.dg/init/array64.C          |  2 +-
 5 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index c5ba82c86648..5a994378451b 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -962,7 +962,9 @@ can_init_array_with_p (tree type, tree init)
        return true;
     }
 
-  return false;
+  permerror (input_location, "array must be initialized "
+            "with a brace-enclosed initializer");
+  return true;
 }
 
 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
diff --git a/gcc/testsuite/g++.dg/diagnostic/aggr-init1.C 
b/gcc/testsuite/g++.dg/diagnostic/aggr-init1.C
new file mode 100644
index 000000000000..b4b2d9e69e1d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/aggr-init1.C
@@ -0,0 +1,37 @@
+// PR c++/116634
+// { dg-do compile { target c++11 } }
+// { dg-additional-options -fpermissive }
+
+namespace std {
+  using size_t = decltype(sizeof(42));
+}
+
+class ConstString final {
+public:
+    constexpr ConstString() noexcept: buf(), len(0) {}
+    template<int N>
+    constexpr ConstString(const char (&a)[N]): buf(a), len(N - 1) {}
+    constexpr ConstString(const ConstString &c1): buf(c1.buf), 
len(static_cast<int>(c1.len)) {}
+
+private:
+    const char* buf;
+    int len;
+};
+
+template<int N>
+struct Any final {
+    constexpr
+    Any(ConstString (&&_vec)[N]) noexcept: vec(_vec){} // { dg-warning "array" 
}
+
+    ConstString vec[N];
+};
+
+template<int... N1>
+constexpr static
+auto Any_of(const char (&...c1)[N1]) -> Any<static_cast<int>(sizeof...(N1))> {
+  return {{ConstString(c1)...}};
+}
+
+int main() {
+  constexpr static const auto aa1 = Any_of("abcd", "def");
+}
diff --git a/gcc/testsuite/g++.dg/init/array62.C 
b/gcc/testsuite/g++.dg/init/array62.C
index 2a786a36e4e8..6d3935d7a668 100644
--- a/gcc/testsuite/g++.dg/init/array62.C
+++ b/gcc/testsuite/g++.dg/init/array62.C
@@ -4,7 +4,7 @@
 struct string {} a[1];
 struct pair {
   string s[1];
-  pair() : s(a) {} // { dg-error "invalid initializer for array member" }
+  pair() : s(a) {} // { dg-error "array must be initialized" }
 };
 
 struct S {
diff --git a/gcc/testsuite/g++.dg/init/array63.C 
b/gcc/testsuite/g++.dg/init/array63.C
index 57e980561680..96bc9a64b26c 100644
--- a/gcc/testsuite/g++.dg/init/array63.C
+++ b/gcc/testsuite/g++.dg/init/array63.C
@@ -7,7 +7,7 @@ struct I {
 struct O {
     I a[2];
     static I const data[2];
-    O() : a(data){}  // { dg-error "invalid initializer for array member" }
+    O() : a(data){}  // { dg-error "array must be initialized" }
 };
 
 I const O::data[2] = {true, false};
diff --git a/gcc/testsuite/g++.dg/init/array64.C 
b/gcc/testsuite/g++.dg/init/array64.C
index e0afdfab39a5..bbdd70c6df8c 100644
--- a/gcc/testsuite/g++.dg/init/array64.C
+++ b/gcc/testsuite/g++.dg/init/array64.C
@@ -16,7 +16,7 @@ typedef UserType Array[my_size];
 class Foo
 {
 public:
-  Foo(Array& m) : m_(m) {};  // { dg-error "invalid initializer for array 
member" }
+  Foo(Array& m) : m_(m) {};  // { dg-error "array must be initialized" }
 private:
   Array m_;
 };