re PR c++/84582 (Rejected valid C++ code since r257961)

	PR c++/84582
	* semantics.c (force_paren_expr): Create a PAREN_EXPR when in
	a template.
	(maybe_undo_parenthesized_ref): Unwrap PAREN_EXPR.
	* typeck2.c (store_init_value): Call fold_non_dependent_expr instead
	of instantiate_non_dependent_expr.
	* tree.c (lvalue_kind): Handle PAREN_EXPR like NON_DEPENDENT_EXPR.

	* g++.dg/cpp1y/auto-fn15.C: Extend testing.
	* g++.dg/cpp1z/static1.C: New test.
	* g++.dg/template/static37.C: New test.

Co-Authored-By: Jason Merrill <jason@redhat.com>

From-SVN: r258116

8 files changed, 69 insertions, 5 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4cb5310..d44845b 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,14 @@
+2018-03-01  Marek Polacek  <polacek@redhat.com>
+	    Jason Merrill  <jason@redhat.com>
+
+	PR c++/84582
+	* semantics.c (force_paren_expr): Create a PAREN_EXPR when in
+	a template.
+	(maybe_undo_parenthesized_ref): Unwrap PAREN_EXPR.
+	* typeck2.c (store_init_value): Call fold_non_dependent_expr instead
+	of instantiate_non_dependent_expr.
+	* tree.c (lvalue_kind): Handle PAREN_EXPR like NON_DEPENDENT_EXPR.
+
 2018-03-01  Nathan Sidwell  <nathan@acm.org>
 
 	PR c++/84434
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 87c5c66..1ac1d23 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -1693,7 +1693,8 @@ force_paren_expr (tree expr)
   if (TREE_CODE (expr) == COMPONENT_REF
       || TREE_CODE (expr) == SCOPE_REF)
     REF_PARENTHESIZED_P (expr) = true;
-  else if (type_dependent_expression_p (expr))
+  else if (type_dependent_expression_p (expr)
+	   || processing_template_decl)
     expr = build1 (PAREN_EXPR, TREE_TYPE (expr), expr);
   else if (VAR_P (expr) && DECL_HARD_REGISTER (expr))
     /* We can't bind a hard register variable to a reference.  */;
@@ -1724,9 +1725,10 @@ force_paren_expr (tree expr)
 tree
 maybe_undo_parenthesized_ref (tree t)
 {
-  if (cxx_dialect >= cxx14
-      && INDIRECT_REF_P (t)
-      && REF_PARENTHESIZED_P (t))
+  if (cxx_dialect < cxx14)
+    return t;
+
+  if (INDIRECT_REF_P (t) && REF_PARENTHESIZED_P (t))
     {
       t = TREE_OPERAND (t, 0);
       while (TREE_CODE (t) == NON_LVALUE_EXPR
@@ -1737,6 +1739,8 @@ maybe_undo_parenthesized_ref (tree t)
 		  || TREE_CODE (t) == STATIC_CAST_EXPR);
       t = TREE_OPERAND (t, 0);
     }
+  else if (TREE_CODE (t) == PAREN_EXPR)
+    t = TREE_OPERAND (t, 0);
 
   return t;
 }
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 9b9e36a..19f1c06 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -239,6 +239,7 @@ lvalue_kind (const_tree ref)
       return lvalue_kind (BASELINK_FUNCTIONS (CONST_CAST_TREE (ref)));
 
     case NON_DEPENDENT_EXPR:
+    case PAREN_EXPR:
       return lvalue_kind (TREE_OPERAND (ref, 0));
 
     case VIEW_CONVERT_EXPR:
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index 153b46c..583c65d 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -822,7 +822,7 @@ store_init_value (tree decl, tree init, vec<tree, va_gc>** cleanups, int flags)
   if (decl_maybe_constant_var_p (decl) || TREE_STATIC (decl))
     {
       bool const_init;
-      value = instantiate_non_dependent_expr (value);
+      value = fold_non_dependent_expr (value);
       if (DECL_DECLARED_CONSTEXPR_P (decl)
 	  || (DECL_IN_AGGR_P (decl) && !DECL_VAR_DECLARED_INLINE_P (decl)))
 	{
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 90b53ae..abd409e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2018-03-01  Marek Polacek  <polacek@redhat.com>
+	    Jason Merrill  <jason@redhat.com>
+
+	PR c++/84582
+	* g++.dg/cpp1y/auto-fn15.C: Extend testing.
+	* g++.dg/cpp1z/static1.C: New test.
+	* g++.dg/template/static37.C: New test.
+
 2018-03-01  Nathan Sidwell  <nathan@acm.org>
 
 	PR c++/84434
diff --git a/gcc/testsuite/g++.dg/cpp1y/auto-fn15.C b/gcc/testsuite/g++.dg/cpp1y/auto-fn15.C
index ba9f357..0db428f 100644
--- a/gcc/testsuite/g++.dg/cpp1y/auto-fn15.C
+++ b/gcc/testsuite/g++.dg/cpp1y/auto-fn15.C
@@ -22,6 +22,8 @@ template <class T>
 decltype(auto) h5(T t) { return t.i; }
 template <class T>
 decltype(auto) h6(T t) { return (t.i); }
+template <class T>
+decltype(auto) h7(T t) { return (i); }
 
 int main()
 {
@@ -48,4 +50,5 @@ int main()
   same_type<decltype(h4()),int&>();
   same_type<decltype(h5(a)),int>();
   same_type<decltype(h6(a)),int&>();
+  same_type<decltype(h7(a)),int&>();
 }
diff --git a/gcc/testsuite/g++.dg/cpp1z/static1.C b/gcc/testsuite/g++.dg/cpp1z/static1.C
new file mode 100644
index 0000000..cb87299
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/static1.C
@@ -0,0 +1,19 @@
+// PR c++/84582
+// { dg-options -std=c++17 }
+
+class C {
+  static inline const long b = 0;
+  static inline const unsigned c = (b);
+};
+class D {
+  static inline const long b = 0;
+  static inline const unsigned c = b;
+};
+template <class> class A {
+  static inline const long b = 0;
+  static inline const unsigned c = (b);
+};
+template <class> class B {
+  static inline const long b = 0;
+  static inline const unsigned c = b;
+};
diff --git a/gcc/testsuite/g++.dg/template/static37.C b/gcc/testsuite/g++.dg/template/static37.C
new file mode 100644
index 0000000..90bc65d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/static37.C
@@ -0,0 +1,18 @@
+// PR c++/84582
+
+class C {
+  static const long b = 0;
+  static const unsigned c = (b);
+};
+class D {
+  static const long b = 0;
+  static const unsigned c = b;
+};
+template <class> class A {
+  static const long b = 0;
+  static const unsigned c = (b);
+};
+template <class> class B {
+  static const long b = 0;
+  static const unsigned c = b;
+};