[gcc/devel/c++-coroutines] c++: Fix ICE in tsubst_copy with parenthesized expression [PR93299]

[Iain D Sandoe]

https://gcc.gnu.org/g:d54a86cd92860e1108f43fae9329ccb0897f3e1d

commit d54a86cd92860e1108f43fae9329ccb0897f3e1d
Author: Marek Polacek <polacek@redhat.com>
Date:   Fri Jan 17 15:17:42 2020 -0500

    c++: Fix ICE in tsubst_copy with parenthesized expression [PR93299]
    
    Since e4511ca2e9ecdb51d41b64452398f8e2df575668 force_paren_expr can create
    a VIEW_CONVERT_EXPR so that we have something to set REF_PARENTHESIZED_P
    on, while not making the expression dependent.  But tsubst_copy can't cope
    with such a VIEW_CONVERT_EXPR, because it's not location_wrapper_p, or
    a TEMPLATE_PARM_INDEX wrapped in a VIEW_CONVERT_EXPR.
    
    I think we need to teach tsubst_copy how to handle it.  Setting
    EXPR_LOCATION_WRAPPER_P in force_paren_expr would make the ICE go away
    too, but tsubst_copy would lose the REF_PARENTHESIZED_P flag.
    
    2020-01-24  Marek Polacek  <polacek@redhat.com>
    
    	PR c++/93299 - ICE in tsubst_copy with parenthesized expression.
    	* pt.c (tsubst_copy): Handle a REF_PARENTHESIZED_P VIEW_CONVERT_EXPR.
    
    	* g++.dg/cpp1y/paren5.C: New test.

Diff:
---
 gcc/cp/ChangeLog                    |  5 +++++
 gcc/cp/pt.c                         |  8 ++++++++
 gcc/testsuite/ChangeLog             |  5 +++++
 gcc/testsuite/g++.dg/cpp1y/paren5.C | 12 ++++++++++++
 4 files changed, 30 insertions(+)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index b1c9e2c..0ed260b 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2020-01-24  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/93299 - ICE in tsubst_copy with parenthesized expression.
+	* pt.c (tsubst_copy): Handle a REF_PARENTHESIZED_P VIEW_CONVERT_EXPR.
+
 2020-01-24  Jason Merrill  <jason@redhat.com>
 
 	PR c++/92852 - ICE with generic lambda and reference var.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 4520c99..9571992 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -16423,6 +16423,14 @@ tsubst_copy (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 		  return op;
 		}
 	    }
+	  /* force_paren_expr can also create a VIEW_CONVERT_EXPR.  */
+	  else if (code == VIEW_CONVERT_EXPR && REF_PARENTHESIZED_P (t))
+	    {
+	      op = tsubst_copy (op, args, complain, in_decl);
+	      op = build1 (code, TREE_TYPE (op), op);
+	      REF_PARENTHESIZED_P (op) = true;
+	      return op;
+	    }
 	  /* We shouldn't see any other uses of these in templates.  */
 	  gcc_unreachable ();
 	}
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7c6b4cd..d1213cc 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-01-24  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/93299 - ICE in tsubst_copy with parenthesized expression.
+	* g++.dg/cpp1y/paren5.C: New test.
+
 2020-01-24  Sandra Loosemore  <sandra@codesourcery.com>
 
 	* g++.dg/cpp0x/constexpr-odr1.C: Add -fdelete-null-pointer-checks.
diff --git a/gcc/testsuite/g++.dg/cpp1y/paren5.C b/gcc/testsuite/g++.dg/cpp1y/paren5.C
new file mode 100644
index 0000000..86a5135
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/paren5.C
@@ -0,0 +1,12 @@
+// PR c++/93299 - ICE in tsubst_copy with parenthesized expression.
+// { dg-do compile { target c++14 } }
+
+template <typename> struct A {
+  enum { b = 8 };
+};
+
+template <int> struct __attribute__((aligned((A<int>::b)))) D { };
+struct S : D<0> { };
+
+template <int N> struct __attribute__((aligned((A<int>::b) + N))) D2 { };
+struct S2 : D2<0> { };