Re: [Patch, Fortran, F03] PR 40996: Allocatable Scalars

[Janus Weil <janus at gcc dot gnu dot org>]

>> > Btw: Do we have a function which checks if one type is an extension
>> > (direct or indirect) of another, or do I have to invent this?
>>
>> Ok, I have implemented this now (updated patch attached).
>>
>> Btw, Steve: I'm wondering about your Fortran Standard references in
>> gfc_match_allocate. What you labeled as C626 seems to be C624 in the
>> version of the standard that I am looking at
>> (http://www.j3-fortran.org/doc/year/04/04-007.pdf). Are you looking at
>> a different version?
>>
>
> Janus,
>
> The patch looks ok to me. ?Paul or tobias may have a comment,
> so you may want to give them a day or two to respond.
>
> Here's a few rather minor comments. ?In that the comments are
> minor, feel free to ignore them.

Thanks, Steve and Daniel, for your comments. I have incorporated all
of them (updated patch attached), in particular:

* I made gfc_type_compatible bool, and used Daniel's gfc_get_super_type inside.
* I renamed match_intrinsic_typespec to match_type_spec, and
gfc_match_type_spec to gfc_match_decl_type_spec, and adjusted the
documentation.

I will regtest the attached version again, and commit later (together
with my test case), unless anyone has further comments.

Cheers,
Janus

Index: gcc/fortran/symbol.c
===================================================================
--- gcc/fortran/symbol.c	(revision 151238)
+++ gcc/fortran/symbol.c	(working copy)
@@ -4534,6 +4534,32 @@ gfc_get_derived_super_type (gfc_symbol* 
 }
 
 
+/* Check if two typespecs are compatible:
+   If ts1 is nonpolymorphic, ts2 must be the same type.
+   If ts1 is polymorphic (CLASS), ts2 must be an extension of ts1.  */
+
+bool
+gfc_type_compatible (gfc_typespec *ts1, gfc_typespec *ts2)
+{
+  if (ts1->type == BT_DERIVED && ts2->type == BT_DERIVED)
+    {
+      gfc_symbol *t0, *t;
+      if (ts1->is_class)
+	{
+	  t0 = ts1->u.derived;
+	  t = ts2->u.derived;
+	  while (t0 != t && t->attr.extension)
+	    t = gfc_get_derived_super_type (t);
+	  return (t0 == t);
+	}
+      else
+	return (ts1->u.derived == ts2->u.derived);
+    }
+  else
+    return (ts1->type == ts2->type);
+}
+
+
 /* General worker function to find either a type-bound procedure or a
    type-bound user operator.  */
 
Index: gcc/fortran/decl.c
===================================================================
--- gcc/fortran/decl.c	(revision 151238)
+++ gcc/fortran/decl.c	(working copy)
@@ -2267,8 +2267,8 @@ done:
 }
 
 
-/* Matches a type specification.  If successful, sets the ts structure
-   to the matched specification.  This is necessary for FUNCTION and
+/* Matches a declaration-type-spec (R502).  If successful, sets the ts
+   structure to the matched specification.  This is necessary for FUNCTION and
    IMPLICIT statements.
 
    If implicit_flag is nonzero, then we don't check for the optional
@@ -2276,7 +2276,7 @@ done:
    statement correctly.  */
 
 match
-gfc_match_type_spec (gfc_typespec *ts, int implicit_flag)
+gfc_match_decl_type_spec (gfc_typespec *ts, int implicit_flag)
 {
   char name[GFC_MAX_SYMBOL_LEN + 1];
   gfc_symbol *sym;
@@ -2599,7 +2599,7 @@ gfc_match_implicit (void)
       gfc_clear_new_implicit ();
 
       /* A basic type is mandatory here.  */
-      m = gfc_match_type_spec (&ts, 1);
+      m = gfc_match_decl_type_spec (&ts, 1);
       if (m == MATCH_ERROR)
 	goto error;
       if (m == MATCH_NO)
@@ -3675,7 +3675,7 @@ gfc_match_data_decl (void)
 
   num_idents_on_line = 0;
   
-  m = gfc_match_type_spec (&current_ts, 0);
+  m = gfc_match_decl_type_spec (&current_ts, 0);
   if (m != MATCH_YES)
     return m;
 
@@ -3780,7 +3780,7 @@ gfc_match_prefix (gfc_typespec *ts)
 
 loop:
   if (!seen_type && ts != NULL
-      && gfc_match_type_spec (ts, 0) == MATCH_YES
+      && gfc_match_decl_type_spec (ts, 0) == MATCH_YES
       && gfc_match_space () == MATCH_YES)
     {
 
@@ -4178,7 +4178,7 @@ match_procedure_interface (gfc_symbol **
 
   /* Get the type spec. for the procedure interface.  */
   old_loc = gfc_current_locus;
-  m = gfc_match_type_spec (&current_ts, 0);
+  m = gfc_match_decl_type_spec (&current_ts, 0);
   gfc_gobble_whitespace ();
   if (m == MATCH_YES || (m == MATCH_NO && gfc_peek_ascii_char () == ')'))
     goto got_ts;
Index: gcc/fortran/array.c
===================================================================
--- gcc/fortran/array.c	(revision 151238)
+++ gcc/fortran/array.c	(working copy)
@@ -907,7 +907,7 @@ gfc_match_array_constructor (gfc_expr **
   seen_ts = false;
 
   /* Try to match an optional "type-spec ::"  */
-  if (gfc_match_type_spec (&ts, 0) == MATCH_YES)
+  if (gfc_match_decl_type_spec (&ts, 0) == MATCH_YES)
     {
       seen_ts = (gfc_match (" ::") == MATCH_YES);
 
Index: gcc/fortran/gfortran.h
===================================================================
--- gcc/fortran/gfortran.h	(revision 151238)
+++ gcc/fortran/gfortran.h	(working copy)
@@ -2469,6 +2469,7 @@ gfc_gsymbol *gfc_find_gsymbol (gfc_gsymb
 
 gfc_typebound_proc* gfc_get_typebound_proc (void);
 gfc_symbol* gfc_get_derived_super_type (gfc_symbol*);
+bool gfc_type_compatible (gfc_typespec *, gfc_typespec *);
 gfc_symtree* gfc_find_typebound_proc (gfc_symbol*, gfc_try*,
 				      const char*, bool, locus*);
 gfc_symtree* gfc_find_typebound_user_op (gfc_symbol*, gfc_try*,
Index: gcc/fortran/match.c
===================================================================
--- gcc/fortran/match.c	(revision 151238)
+++ gcc/fortran/match.c	(working copy)
@@ -2221,21 +2221,22 @@ gfc_free_alloc_list (gfc_alloc *p)
 }
 
 
-/* Match a Fortran 2003 intrinsic-type-spec.  This is a stripped
-   down version of gfc_match_type_spec() from decl.c.  It only includes
-   the intrinsic types from the Fortran 2003 standard.  Thus, neither
-   BYTE nor forms like REAL*4 are allowed.  Additionally, the implicit_flag
-   is not needed, so it was removed.  The handling of derived types has
-   been removed and no notion of the gfc_matching_function state
-   is needed.  In short, this functions matches only standard conforming
-   intrinsic-type-spec (R403).  */
+/* Match a Fortran 2003 type-spec (R401).  This is similar to
+   gfc_match_decl_type_spec() from decl.c, with the following exceptions:
+   It only includes the intrinsic types from the Fortran 2003 standard
+   (thus, neither BYTE nor forms like REAL*4 are allowed). Additionally,
+   the implicit_flag is not needed, so it was removed.  Derived types are
+   identified by their name alone.  */
 
 static match
-match_intrinsic_typespec (gfc_typespec *ts)
+match_type_spec (gfc_typespec *ts)
 {
   match m;
+  gfc_symbol *derived;
+  locus old_locus;
 
   gfc_clear_ts (ts);
+  old_locus = gfc_current_locus;
 
   if (gfc_match ("integer") == MATCH_YES)
     {
@@ -2278,7 +2279,43 @@ match_intrinsic_typespec (gfc_typespec *
       goto kind_selector;
     }
 
-  /* If an intrinsic type is not matched, simply return MATCH_NO.  */ 
+  if (gfc_match_symbol (&derived, 1) == MATCH_YES)
+    {
+      if (derived->attr.flavor == FL_DERIVED)
+	{
+	  old_locus = gfc_current_locus;
+	  if (gfc_match (" :: ") != MATCH_YES)
+	    return MATCH_ERROR;
+	  gfc_current_locus = old_locus;
+	  ts->type = BT_DERIVED;
+	  ts->u.derived = derived;
+	  /* Enfore C401 (F03).  */
+	  if (derived->attr.abstract)
+	    {
+	      gfc_error ("Derived type '%s' at %L may not be ABSTRACT",
+			 derived->name, &old_locus);
+	      return MATCH_ERROR;
+	    }
+	  return MATCH_YES;
+	}
+      else
+	{
+	  if (gfc_match (" :: ") == MATCH_YES)
+	    {
+	      /* Enforce C476 (F03).  */
+	      gfc_error ("'%s' at %L is not an accessible derived type",
+			 derived->name, &old_locus);
+	      return MATCH_ERROR;
+	    }
+	  else
+	    {
+	      gfc_current_locus = old_locus;
+	      return MATCH_NO;
+	    }
+	}
+    }
+
+  /* If a type is not matched, simply return MATCH_NO.  */ 
   return MATCH_NO;
 
 kind_selector:
@@ -2379,9 +2416,9 @@ gfc_match_allocate (void)
   if (gfc_match_char ('(') != MATCH_YES)
     goto syntax;
 
-  /* Match an optional intrinsic-type-spec.  */
+  /* Match an optional type-spec.  */
   old_locus = gfc_current_locus;
-  m = match_intrinsic_typespec (&ts);
+  m = match_type_spec (&ts);
   if (m == MATCH_ERROR)
     goto cleanup;
   else if (m == MATCH_NO)
@@ -2430,15 +2467,15 @@ gfc_match_allocate (void)
 	 constraints.  */
       if (ts.type != BT_UNKNOWN)
 	{
-	  /* Enforce C626.  */
-	  if (ts.type != tail->expr->ts.type)
+	  /* Enforce C624 (F03).  */
+	  if (!gfc_type_compatible (&tail->expr->ts, &ts))
 	    {
 	      gfc_error ("Type of entity at %L is type incompatible with "
 			 "typespec", &tail->expr->where);
 	      goto cleanup;
 	    }
 
-	  /* Enforce C627.  */
+	  /* Enforce C625 (F03).  */
 	  if (ts.kind != tail->expr->ts.kind)
 	    {
 	      gfc_error ("Kind type parameter for entity at %L differs from "
Index: gcc/fortran/match.h
===================================================================
--- gcc/fortran/match.h	(revision 151238)
+++ gcc/fortran/match.h	(working copy)
@@ -138,7 +138,7 @@ match gfc_match_data (void);
 match gfc_match_null (gfc_expr **);
 match gfc_match_kind_spec (gfc_typespec *, bool);
 match gfc_match_old_kind_spec (gfc_typespec *);
-match gfc_match_type_spec (gfc_typespec *, int);
+match gfc_match_decl_type_spec (gfc_typespec *, int);
 
 match gfc_match_end (gfc_statement *);
 match gfc_match_data_decl (void);