re PR fortran/24158 (ICE in f951 with nested, recursive derived types)

2005-10-26  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/24158
	* decl.c (gfc_match_data_decl): Correct broken bit of code
	that prevents undefined derived types from being used as
	components of another derived type.
	* resolve.c (resolve_symbol): Add backstop error when derived
	type variables arrive here with a type that has no components.

2005-10-26  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/24158
	gfortran.dg/derived_recursion.f90: New test.
	gfortran.dg/implicit_actual.f90: New test.

From-SVN: r105913

3 files changed, 39 insertions, 8 deletions

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 233f149..2cfea31 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,12 @@
+2005-10-26  Paul Thomas  <pault@gcc.gnu.org>
+
+	PR fortran/24158
+	* decl.c (gfc_match_data_decl): Correct broken bit of code
+	that prevents undefined derived types from being used as
+	components of another derived type.
+	* resolve.c (resolve_symbol): Add backstop error when derived
+	type variables arrive here with a type that has no components.
+
 2005-10-25  Jakub Jelinek  <jakub@redhat.com>
 
 	* trans.h (gfc_conv_cray_pointee): Remove.
diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index 5d4bd56..8c2895ed 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -2075,17 +2075,21 @@ gfc_match_data_decl (void)
       if (current_attr.pointer && gfc_current_state () == COMP_DERIVED)
 	goto ok;
 
-      if (gfc_find_symbol (current_ts.derived->name,
-			   current_ts.derived->ns->parent, 1, &sym) == 0)
-	goto ok;
+      gfc_find_symbol (current_ts.derived->name,
+			 current_ts.derived->ns->parent, 1, &sym);
 
-      /* Hope that an ambiguous symbol is itself masked by a type definition.  */
-      if (sym != NULL && sym->attr.flavor == FL_DERIVED)
+      /* Any symbol that we find had better be a type definition
+         which has its components defined.  */
+      if (sym != NULL && sym->attr.flavor == FL_DERIVED
+	    && current_ts.derived->components != NULL)
 	goto ok;
 
-      gfc_error ("Derived type at %C has not been previously defined");
-      m = MATCH_ERROR;
-      goto cleanup;
+      /* Now we have an error, which we signal, and then fix up
+	 because the knock-on is plain and simple confusing.  */
+      gfc_error_now ("Derived type at %C has not been previously defined "
+		 "and so cannot appear in a derived type definition.");
+      current_attr.pointer = 1;
+      goto ok;
     }
 
 ok:
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 6c03126..03206bb 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -4339,6 +4339,24 @@ resolve_symbol (gfc_symbol * sym)
         }
     }
 
+  /* If a derived type symbol has reached this point, without its
+     type being declared, we have an error.  Notice that most
+     conditions that produce undefined derived types have already
+     been dealt with.  However, the likes of:
+     implicit type(t) (t) ..... call foo (t) will get us here if
+     the type is not declared in the scope of the implicit
+     statement. Change the type to BT_UNKNOWN, both because it is so
+     and to prevent an ICE.  */
+  if (sym->ts.type == BT_DERIVED
+	&& sym->ts.derived->components == NULL)
+    {
+      gfc_error ("The derived type '%s' at %L is of type '%s', "
+		 "which has not been defined.", sym->name,
+		  &sym->declared_at, sym->ts.derived->name);
+      sym->ts.type = BT_UNKNOWN;
+      return;
+    }
+
   /* Ensure that derived type components of a public derived type
      are not of a private type.  */
   if (sym->attr.flavor == FL_DERIVED