[C++ Patch] PR 90173 ("[9 Regression] ICE: Segmentation fault (in strip_declarator_types)")

[Paolo Carlini]

Hi,

I tried a few different things to avoid this simple error-recovery 
regression but, all in all, I think it makes sense to simply bail out 
early from grokdeclarator upon the first error. Tested x86_64-linux.

Thanks, Paolo.

///////////////////

/cp
2019-04-23  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/90173
        * decl.c (grokdeclarator): Early return error_mark_node
        upon error about template placeholder type non followed
        by a simple declarator-id.

/testsuite
2019-04-23  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/90173
        * g++.dg/cpp1z/class-deduction66.C: New.
Index: cp/decl.c
===================================================================
--- cp/decl.c   (revision 270500)
+++ cp/decl.c   (working copy)
@@ -10973,6 +10973,7 @@ grokdeclarator (const cp_declarator *declarator,
       error_at (typespec_loc, "template placeholder type %qT must be followed "
                "by a simple declarator-id", type);
       inform (DECL_SOURCE_LOCATION (tmpl), "%qD declared here", tmpl);
+      return error_mark_node;
     }
 
   staticp = 0;
Index: testsuite/g++.dg/cpp1z/class-deduction66.C
===================================================================
--- testsuite/g++.dg/cpp1z/class-deduction66.C  (nonexistent)
+++ testsuite/g++.dg/cpp1z/class-deduction66.C  (working copy)
@@ -0,0 +1,10 @@
+// PR c++/90173
+// { dg-do run { target c++17 } }
+
+template <typename T> struct A { };
+
+A(int) -> A<int>;
+
+namespace decl {
+  A (*fp)() = 0;  // { dg-error "placeholder" }
+}