Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 3328 insertions, 0 deletions

diff --git a/gcc-4.9/gcc/fortran/primary.c b/gcc-4.9/gcc/fortran/primary.c
new file mode 100644
index 000000000..e2eb46748
--- /dev/null
+++ b/gcc-4.9/gcc/fortran/primary.c
@@ -0,0 +1,3328 @@
+/* Primary expression subroutines
+   Copyright (C) 2000-2014 Free Software Foundation, Inc.
+   Contributed by Andy Vaught
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "flags.h"
+#include "gfortran.h"
+#include "arith.h"
+#include "match.h"
+#include "parse.h"
+#include "constructor.h"
+
+int matching_actual_arglist = 0;
+
+/* Matches a kind-parameter expression, which is either a named
+   symbolic constant or a nonnegative integer constant.  If
+   successful, sets the kind value to the correct integer.
+   The argument 'is_iso_c' signals whether the kind is an ISO_C_BINDING
+   symbol like e.g. 'c_int'.  */
+
+static match
+match_kind_param (int *kind, int *is_iso_c)
+{
+  char name[GFC_MAX_SYMBOL_LEN + 1];
+  gfc_symbol *sym;
+  const char *p;
+  match m;
+
+  *is_iso_c = 0;
+
+  m = gfc_match_small_literal_int (kind, NULL);
+  if (m != MATCH_NO)
+    return m;
+
+  m = gfc_match_name (name);
+  if (m != MATCH_YES)
+    return m;
+
+  if (gfc_find_symbol (name, NULL, 1, &sym))
+    return MATCH_ERROR;
+
+  if (sym == NULL)
+    return MATCH_NO;
+
+  *is_iso_c = sym->attr.is_iso_c;
+
+  if (sym->attr.flavor != FL_PARAMETER)
+    return MATCH_NO;
+
+  if (sym->value == NULL)
+    return MATCH_NO;
+
+  p = gfc_extract_int (sym->value, kind);
+  if (p != NULL)
+    return MATCH_NO;
+
+  gfc_set_sym_referenced (sym);
+
+  if (*kind < 0)
+    return MATCH_NO;
+
+  return MATCH_YES;
+}
+
+
+/* Get a trailing kind-specification for non-character variables.
+   Returns:
+     * the integer kind value or
+     * -1 if an error was generated,
+     * -2 if no kind was found.
+   The argument 'is_iso_c' signals whether the kind is an ISO_C_BINDING
+   symbol like e.g. 'c_int'.  */
+
+static int
+get_kind (int *is_iso_c)
+{
+  int kind;
+  match m;
+
+  *is_iso_c = 0;
+
+  if (gfc_match_char ('_') != MATCH_YES)
+    return -2;
+
+  m = match_kind_param (&kind, is_iso_c);
+  if (m == MATCH_NO)
+    gfc_error ("Missing kind-parameter at %C");
+
+  return (m == MATCH_YES) ? kind : -1;
+}
+
+
+/* Given a character and a radix, see if the character is a valid
+   digit in that radix.  */
+
+int
+gfc_check_digit (char c, int radix)
+{
+  int r;
+
+  switch (radix)
+    {
+    case 2:
+      r = ('0' <= c && c <= '1');
+      break;
+
+    case 8:
+      r = ('0' <= c && c <= '7');
+      break;
+
+    case 10:
+      r = ('0' <= c && c <= '9');
+      break;
+
+    case 16:
+      r = ISXDIGIT (c);
+      break;
+
+    default:
+      gfc_internal_error ("gfc_check_digit(): bad radix");
+    }
+
+  return r;
+}
+
+
+/* Match the digit string part of an integer if signflag is not set,
+   the signed digit string part if signflag is set.  If the buffer 
+   is NULL, we just count characters for the resolution pass.  Returns 
+   the number of characters matched, -1 for no match.  */
+
+static int
+match_digits (int signflag, int radix, char *buffer)
+{
+  locus old_loc;
+  int length;
+  char c;
+
+  length = 0;
+  c = gfc_next_ascii_char ();
+
+  if (signflag && (c == '+' || c == '-'))
+    {
+      if (buffer != NULL)
+	*buffer++ = c;
+      gfc_gobble_whitespace ();
+      c = gfc_next_ascii_char ();
+      length++;
+    }
+
+  if (!gfc_check_digit (c, radix))
+    return -1;
+
+  length++;
+  if (buffer != NULL)
+    *buffer++ = c;
+
+  for (;;)
+    {
+      old_loc = gfc_current_locus;
+      c = gfc_next_ascii_char ();
+
+      if (!gfc_check_digit (c, radix))
+	break;
+
+      if (buffer != NULL)
+	*buffer++ = c;
+      length++;
+    }
+
+  gfc_current_locus = old_loc;
+
+  return length;
+}
+
+
+/* Match an integer (digit string and optional kind).  
+   A sign will be accepted if signflag is set.  */
+
+static match
+match_integer_constant (gfc_expr **result, int signflag)
+{
+  int length, kind, is_iso_c;
+  locus old_loc;
+  char *buffer;
+  gfc_expr *e;
+
+  old_loc = gfc_current_locus;
+  gfc_gobble_whitespace ();
+
+  length = match_digits (signflag, 10, NULL);
+  gfc_current_locus = old_loc;
+  if (length == -1)
+    return MATCH_NO;
+
+  buffer = (char *) alloca (length + 1);
+  memset (buffer, '\0', length + 1);
+
+  gfc_gobble_whitespace ();
+
+  match_digits (signflag, 10, buffer);
+
+  kind = get_kind (&is_iso_c);
+  if (kind == -2)
+    kind = gfc_default_integer_kind;
+  if (kind == -1)
+    return MATCH_ERROR;
+
+  if (kind == 4 && gfc_option.flag_integer4_kind == 8)
+    kind = 8;
+
+  if (gfc_validate_kind (BT_INTEGER, kind, true) < 0)
+    {
+      gfc_error ("Integer kind %d at %C not available", kind);
+      return MATCH_ERROR;
+    }
+
+  e = gfc_convert_integer (buffer, kind, 10, &gfc_current_locus);
+  e->ts.is_c_interop = is_iso_c;
+
+  if (gfc_range_check (e) != ARITH_OK)
+    {
+      gfc_error ("Integer too big for its kind at %C. This check can be "
+		 "disabled with the option -fno-range-check");
+
+      gfc_free_expr (e);
+      return MATCH_ERROR;
+    }
+
+  *result = e;
+  return MATCH_YES;
+}
+
+
+/* Match a Hollerith constant.  */
+
+static match
+match_hollerith_constant (gfc_expr **result)
+{
+  locus old_loc;
+  gfc_expr *e = NULL;
+  const char *msg;
+  int num, pad;
+  int i;  
+
+  old_loc = gfc_current_locus;
+  gfc_gobble_whitespace ();
+
+  if (match_integer_constant (&e, 0) == MATCH_YES
+      && gfc_match_char ('h') == MATCH_YES)
+    {
+      if (!gfc_notify_std (GFC_STD_LEGACY, "Hollerith constant at %C"))
+	goto cleanup;
+
+      msg = gfc_extract_int (e, &num);
+      if (msg != NULL)
+	{
+	  gfc_error (msg);
+	  goto cleanup;
+	}
+      if (num == 0)
+	{
+	  gfc_error ("Invalid Hollerith constant: %L must contain at least "
+		     "one character", &old_loc);
+	  goto cleanup;
+	}
+      if (e->ts.kind != gfc_default_integer_kind)
+	{
+	  gfc_error ("Invalid Hollerith constant: Integer kind at %L "
+		     "should be default", &old_loc);
+	  goto cleanup;
+	}
+      else
+	{
+	  gfc_free_expr (e);
+	  e = gfc_get_constant_expr (BT_HOLLERITH, gfc_default_character_kind,
+				     &gfc_current_locus);
+
+	  /* Calculate padding needed to fit default integer memory.  */
+	  pad = gfc_default_integer_kind - (num % gfc_default_integer_kind);
+
+	  e->representation.string = XCNEWVEC (char, num + pad + 1);
+
+	  for (i = 0; i < num; i++)
+	    {
+	      gfc_char_t c = gfc_next_char_literal (INSTRING_WARN);
+	      if (! gfc_wide_fits_in_byte (c))
+		{
+		  gfc_error ("Invalid Hollerith constant at %L contains a "
+			     "wide character", &old_loc);
+		  goto cleanup;
+		}
+
+	      e->representation.string[i] = (unsigned char) c;
+	    }
+
+	  /* Now pad with blanks and end with a null char.  */
+	  for (i = 0; i < pad; i++)
+	    e->representation.string[num + i] = ' ';
+
+	  e->representation.string[num + i] = '\0';
+	  e->representation.length = num + pad;
+	  e->ts.u.pad = pad;
+
+	  *result = e;
+	  return MATCH_YES;
+	}
+    }
+
+  gfc_free_expr (e);
+  gfc_current_locus = old_loc;
+  return MATCH_NO;
+
+cleanup:
+  gfc_free_expr (e);
+  return MATCH_ERROR;
+}
+
+
+/* Match a binary, octal or hexadecimal constant that can be found in
+   a DATA statement.  The standard permits b'010...', o'73...', and
+   z'a1...' where b, o, and z can be capital letters.  This function
+   also accepts postfixed forms of the constants: '01...'b, '73...'o,
+   and 'a1...'z.  An additional extension is the use of x for z.  */
+
+static match
+match_boz_constant (gfc_expr **result)
+{
+  int radix, length, x_hex, kind;
+  locus old_loc, start_loc;
+  char *buffer, post, delim;
+  gfc_expr *e;
+
+  start_loc = old_loc = gfc_current_locus;
+  gfc_gobble_whitespace ();
+
+  x_hex = 0;
+  switch (post = gfc_next_ascii_char ())
+    {
+    case 'b':
+      radix = 2;
+      post = 0;
+      break;
+    case 'o':
+      radix = 8;
+      post = 0;
+      break;
+    case 'x':
+      x_hex = 1;
+      /* Fall through.  */
+    case 'z':
+      radix = 16;
+      post = 0;
+      break;
+    case '\'':
+      /* Fall through.  */
+    case '\"':
+      delim = post;
+      post = 1;
+      radix = 16;  /* Set to accept any valid digit string.  */
+      break;
+    default:
+      goto backup;
+    }
+
+  /* No whitespace allowed here.  */
+
+  if (post == 0)
+    delim = gfc_next_ascii_char ();
+
+  if (delim != '\'' && delim != '\"')
+    goto backup;
+
+  if (x_hex
+      && (!gfc_notify_std(GFC_STD_GNU, "Hexadecimal "
+			  "constant at %C uses non-standard syntax")))
+      return MATCH_ERROR;
+
+  old_loc = gfc_current_locus;
+
+  length = match_digits (0, radix, NULL);
+  if (length == -1)
+    {
+      gfc_error ("Empty set of digits in BOZ constant at %C");
+      return MATCH_ERROR;
+    }
+
+  if (gfc_next_ascii_char () != delim)
+    {
+      gfc_error ("Illegal character in BOZ constant at %C");
+      return MATCH_ERROR;
+    }
+
+  if (post == 1)
+    {
+      switch (gfc_next_ascii_char ())
+	{
+	case 'b':
+	  radix = 2;
+	  break;
+	case 'o':
+	  radix = 8;
+	  break;
+	case 'x':
+	  /* Fall through.  */
+	case 'z':
+	  radix = 16;
+	  break;
+	default:
+	  goto backup;
+	}
+
+      if (!gfc_notify_std (GFC_STD_GNU, "BOZ constant "
+			   "at %C uses non-standard postfix syntax"))
+	return MATCH_ERROR;
+    }
+
+  gfc_current_locus = old_loc;
+
+  buffer = (char *) alloca (length + 1);
+  memset (buffer, '\0', length + 1);
+
+  match_digits (0, radix, buffer);
+  gfc_next_ascii_char ();    /* Eat delimiter.  */
+  if (post == 1)
+    gfc_next_ascii_char ();  /* Eat postfixed b, o, z, or x.  */
+
+  /* In section 5.2.5 and following C567 in the Fortran 2003 standard, we find
+     "If a data-stmt-constant is a boz-literal-constant, the corresponding
+     variable shall be of type integer.  The boz-literal-constant is treated
+     as if it were an int-literal-constant with a kind-param that specifies
+     the representation method with the largest decimal exponent range
+     supported by the processor."  */
+
+  kind = gfc_max_integer_kind;
+  e = gfc_convert_integer (buffer, kind, radix, &gfc_current_locus);
+
+  /* Mark as boz variable.  */
+  e->is_boz = 1;
+
+  if (gfc_range_check (e) != ARITH_OK)
+    {
+      gfc_error ("Integer too big for integer kind %i at %C", kind);
+      gfc_free_expr (e);
+      return MATCH_ERROR;
+    }
+
+  if (!gfc_in_match_data ()
+      && (!gfc_notify_std(GFC_STD_F2003, "BOZ used outside a DATA "
+			  "statement at %C")))
+      return MATCH_ERROR;
+
+  *result = e;
+  return MATCH_YES;
+
+backup:
+  gfc_current_locus = start_loc;
+  return MATCH_NO;
+}
+
+
+/* Match a real constant of some sort.  Allow a signed constant if signflag
+   is nonzero.  */
+
+static match
+match_real_constant (gfc_expr **result, int signflag)
+{
+  int kind, count, seen_dp, seen_digits, is_iso_c;
+  locus old_loc, temp_loc;
+  char *p, *buffer, c, exp_char;
+  gfc_expr *e;
+  bool negate;
+
+  old_loc = gfc_current_locus;
+  gfc_gobble_whitespace ();
+
+  e = NULL;
+
+  count = 0;
+  seen_dp = 0;
+  seen_digits = 0;
+  exp_char = ' ';
+  negate = FALSE;
+
+  c = gfc_next_ascii_char ();
+  if (signflag && (c == '+' || c == '-'))
+    {
+      if (c == '-')
+	negate = TRUE;
+
+      gfc_gobble_whitespace ();
+      c = gfc_next_ascii_char ();
+    }
+
+  /* Scan significand.  */
+  for (;; c = gfc_next_ascii_char (), count++)
+    {
+      if (c == '.')
+	{
+	  if (seen_dp)
+	    goto done;
+
+	  /* Check to see if "." goes with a following operator like 
+	     ".eq.".  */
+	  temp_loc = gfc_current_locus;
+	  c = gfc_next_ascii_char ();
+
+	  if (c == 'e' || c == 'd' || c == 'q')
+	    {
+	      c = gfc_next_ascii_char ();
+	      if (c == '.')
+		goto done;	/* Operator named .e. or .d.  */
+	    }
+
+	  if (ISALPHA (c))
+	    goto done;		/* Distinguish 1.e9 from 1.eq.2 */
+
+	  gfc_current_locus = temp_loc;
+	  seen_dp = 1;
+	  continue;
+	}
+
+      if (ISDIGIT (c))
+	{
+	  seen_digits = 1;
+	  continue;
+	}
+
+      break;
+    }
+
+  if (!seen_digits || (c != 'e' && c != 'd' && c != 'q'))
+    goto done;
+  exp_char = c;
+
+
+  if (c == 'q')
+    {
+      if (!gfc_notify_std (GFC_STD_GNU, "exponent-letter 'q' in "
+			   "real-literal-constant at %C"))
+	return MATCH_ERROR;
+      else if (gfc_option.warn_real_q_constant)
+	gfc_warning("Extension: exponent-letter 'q' in real-literal-constant "
+		    "at %C");
+    }
+
+  /* Scan exponent.  */
+  c = gfc_next_ascii_char ();
+  count++;
+
+  if (c == '+' || c == '-')
+    {				/* optional sign */
+      c = gfc_next_ascii_char ();
+      count++;
+    }
+
+  if (!ISDIGIT (c))
+    {
+      gfc_error ("Missing exponent in real number at %C");
+      return MATCH_ERROR;
+    }
+
+  while (ISDIGIT (c))
+    {
+      c = gfc_next_ascii_char ();
+      count++;
+    }
+
+done:
+  /* Check that we have a numeric constant.  */
+  if (!seen_digits || (!seen_dp && exp_char == ' '))
+    {
+      gfc_current_locus = old_loc;
+      return MATCH_NO;
+    }
+
+  /* Convert the number.  */
+  gfc_current_locus = old_loc;
+  gfc_gobble_whitespace ();
+
+  buffer = (char *) alloca (count + 1);
+  memset (buffer, '\0', count + 1);
+
+  p = buffer;
+  c = gfc_next_ascii_char ();
+  if (c == '+' || c == '-')
+    {
+      gfc_gobble_whitespace ();
+      c = gfc_next_ascii_char ();
+    }
+
+  /* Hack for mpfr_set_str().  */
+  for (;;)
+    {
+      if (c == 'd' || c == 'q')
+	*p = 'e';
+      else
+	*p = c;
+      p++;
+      if (--count == 0)
+	break;
+
+      c = gfc_next_ascii_char ();
+    }
+
+  kind = get_kind (&is_iso_c);
+  if (kind == -1)
+    goto cleanup;
+
+  switch (exp_char)
+    {
+    case 'd':
+      if (kind != -2)
+	{
+	  gfc_error ("Real number at %C has a 'd' exponent and an explicit "
+		     "kind");
+	  goto cleanup;
+	}
+      kind = gfc_default_double_kind;
+
+      if (kind == 4)
+	{
+	  if (gfc_option.flag_real4_kind == 8)
+	    kind = 8;
+	  if (gfc_option.flag_real4_kind == 10)
+	    kind = 10;
+	  if (gfc_option.flag_real4_kind == 16)
+	    kind = 16;
+	}
+
+      if (kind == 8)
+	{
+	  if (gfc_option.flag_real8_kind == 4)
+	    kind = 4;
+	  if (gfc_option.flag_real8_kind == 10)
+	    kind = 10;
+	  if (gfc_option.flag_real8_kind == 16)
+	    kind = 16;
+	}
+      break;
+
+    case 'q':
+      if (kind != -2)
+	{
+	  gfc_error ("Real number at %C has a 'q' exponent and an explicit "
+		     "kind");
+	  goto cleanup;
+	}
+
+      /* The maximum possible real kind type parameter is 16.  First, try
+	 that for the kind, then fallback to trying kind=10 (Intel 80 bit)
+	 extended precision.  If neither value works, just given up.  */
+      kind = 16;
+      if (gfc_validate_kind (BT_REAL, kind, true) < 0)
+	{
+	  kind = 10;
+          if (gfc_validate_kind (BT_REAL, kind, true) < 0)
+	    {
+	      gfc_error ("Invalid exponent-letter 'q' in "
+			 "real-literal-constant at %C");
+	      goto cleanup;
+	    }
+	}
+      break;
+
+    default:
+      if (kind == -2)
+	kind = gfc_default_real_kind;
+
+      if (kind == 4)
+	{
+	  if (gfc_option.flag_real4_kind == 8)
+	    kind = 8;
+	  if (gfc_option.flag_real4_kind == 10)
+	    kind = 10;
+	  if (gfc_option.flag_real4_kind == 16)
+	    kind = 16;
+	}
+
+      if (kind == 8)
+	{
+	  if (gfc_option.flag_real8_kind == 4)
+	    kind = 4;
+	  if (gfc_option.flag_real8_kind == 10)
+	    kind = 10;
+	  if (gfc_option.flag_real8_kind == 16)
+	    kind = 16;
+	}
+
+      if (gfc_validate_kind (BT_REAL, kind, true) < 0)
+	{
+	  gfc_error ("Invalid real kind %d at %C", kind);
+	  goto cleanup;
+	}
+    }
+
+  e = gfc_convert_real (buffer, kind, &gfc_current_locus);
+  if (negate)
+    mpfr_neg (e->value.real, e->value.real, GFC_RND_MODE);
+  e->ts.is_c_interop = is_iso_c;
+
+  switch (gfc_range_check (e))
+    {
+    case ARITH_OK:
+      break;
+    case ARITH_OVERFLOW:
+      gfc_error ("Real constant overflows its kind at %C");
+      goto cleanup;
+
+    case ARITH_UNDERFLOW:
+      if (gfc_option.warn_underflow)
+	gfc_warning ("Real constant underflows its kind at %C");
+      mpfr_set_ui (e->value.real, 0, GFC_RND_MODE);
+      break;
+
+    default:
+      gfc_internal_error ("gfc_range_check() returned bad value");
+    }
+
+  *result = e;
+  return MATCH_YES;
+
+cleanup:
+  gfc_free_expr (e);
+  return MATCH_ERROR;
+}
+
+
+/* Match a substring reference.  */
+
+static match
+match_substring (gfc_charlen *cl, int init, gfc_ref **result)
+{
+  gfc_expr *start, *end;
+  locus old_loc;
+  gfc_ref *ref;
+  match m;
+
+  start = NULL;
+  end = NULL;
+
+  old_loc = gfc_current_locus;
+
+  m = gfc_match_char ('(');
+  if (m != MATCH_YES)
+    return MATCH_NO;
+
+  if (gfc_match_char (':') != MATCH_YES)
+    {
+      if (init)
+	m = gfc_match_init_expr (&start);
+      else
+	m = gfc_match_expr (&start);
+
+      if (m != MATCH_YES)
+	{
+	  m = MATCH_NO;
+	  goto cleanup;
+	}
+
+      m = gfc_match_char (':');
+      if (m != MATCH_YES)
+	goto cleanup;
+    }
+
+  if (gfc_match_char (')') != MATCH_YES)
+    {
+      if (init)
+	m = gfc_match_init_expr (&end);
+      else
+	m = gfc_match_expr (&end);
+
+      if (m == MATCH_NO)
+	goto syntax;
+      if (m == MATCH_ERROR)
+	goto cleanup;
+
+      m = gfc_match_char (')');
+      if (m == MATCH_NO)
+	goto syntax;
+    }
+
+  /* Optimize away the (:) reference.  */
+  if (start == NULL && end == NULL)
+    ref = NULL;
+  else
+    {
+      ref = gfc_get_ref ();
+
+      ref->type = REF_SUBSTRING;
+      if (start == NULL)
+	start = gfc_get_int_expr (gfc_default_integer_kind, NULL, 1);
+      ref->u.ss.start = start;
+      if (end == NULL && cl)
+	end = gfc_copy_expr (cl->length);
+      ref->u.ss.end = end;
+      ref->u.ss.length = cl;
+    }
+
+  *result = ref;
+  return MATCH_YES;
+
+syntax:
+  gfc_error ("Syntax error in SUBSTRING specification at %C");
+  m = MATCH_ERROR;
+
+cleanup:
+  gfc_free_expr (start);
+  gfc_free_expr (end);
+
+  gfc_current_locus = old_loc;
+  return m;
+}
+
+
+/* Reads the next character of a string constant, taking care to
+   return doubled delimiters on the input as a single instance of
+   the delimiter.
+
+   Special return values for "ret" argument are:
+     -1   End of the string, as determined by the delimiter
+     -2   Unterminated string detected
+
+   Backslash codes are also expanded at this time.  */
+
+static gfc_char_t
+next_string_char (gfc_char_t delimiter, int *ret)
+{
+  locus old_locus;
+  gfc_char_t c;
+
+  c = gfc_next_char_literal (INSTRING_WARN);
+  *ret = 0;
+
+  if (c == '\n')
+    {
+      *ret = -2;
+      return 0;
+    }
+
+  if (gfc_option.flag_backslash && c == '\\')
+    {
+      old_locus = gfc_current_locus;
+
+      if (gfc_match_special_char (&c) == MATCH_NO)
+	gfc_current_locus = old_locus;
+
+      if (!(gfc_option.allow_std & GFC_STD_GNU) && !inhibit_warnings)
+	gfc_warning ("Extension: backslash character at %C");
+    }
+
+  if (c != delimiter)
+    return c;
+
+  old_locus = gfc_current_locus;
+  c = gfc_next_char_literal (NONSTRING);
+
+  if (c == delimiter)
+    return c;
+  gfc_current_locus = old_locus;
+
+  *ret = -1;
+  return 0;
+}
+
+
+/* Special case of gfc_match_name() that matches a parameter kind name
+   before a string constant.  This takes case of the weird but legal
+   case of:
+
+     kind_____'string'
+
+   where kind____ is a parameter. gfc_match_name() will happily slurp
+   up all the underscores, which leads to problems.  If we return
+   MATCH_YES, the parse pointer points to the final underscore, which
+   is not part of the name.  We never return MATCH_ERROR-- errors in
+   the name will be detected later.  */
+
+static match
+match_charkind_name (char *name)
+{
+  locus old_loc;
+  char c, peek;
+  int len;
+
+  gfc_gobble_whitespace ();
+  c = gfc_next_ascii_char ();
+  if (!ISALPHA (c))
+    return MATCH_NO;
+
+  *name++ = c;
+  len = 1;
+
+  for (;;)
+    {
+      old_loc = gfc_current_locus;
+      c = gfc_next_ascii_char ();
+
+      if (c == '_')
+	{
+	  peek = gfc_peek_ascii_char ();
+
+	  if (peek == '\'' || peek == '\"')
+	    {
+	      gfc_current_locus = old_loc;
+	      *name = '\0';
+	      return MATCH_YES;
+	    }
+	}
+
+      if (!ISALNUM (c)
+	  && c != '_'
+	  && (c != '$' || !gfc_option.flag_dollar_ok))
+	break;
+
+      *name++ = c;
+      if (++len > GFC_MAX_SYMBOL_LEN)
+	break;
+    }
+
+  return MATCH_NO;
+}
+
+
+/* See if the current input matches a character constant.  Lots of
+   contortions have to be done to match the kind parameter which comes
+   before the actual string.  The main consideration is that we don't
+   want to error out too quickly.  For example, we don't actually do
+   any validation of the kinds until we have actually seen a legal
+   delimiter.  Using match_kind_param() generates errors too quickly.  */
+
+static match
+match_string_constant (gfc_expr **result)
+{
+  char name[GFC_MAX_SYMBOL_LEN + 1], peek;
+  int i, kind, length, warn_ampersand, ret;
+  locus old_locus, start_locus;
+  gfc_symbol *sym;
+  gfc_expr *e;
+  const char *q;
+  match m;
+  gfc_char_t c, delimiter, *p;
+
+  old_locus = gfc_current_locus;
+
+  gfc_gobble_whitespace ();
+
+  c = gfc_next_char ();
+  if (c == '\'' || c == '"')
+    {
+      kind = gfc_default_character_kind;
+      start_locus = gfc_current_locus;
+      goto got_delim;
+    }
+
+  if (gfc_wide_is_digit (c))
+    {
+      kind = 0;
+
+      while (gfc_wide_is_digit (c))
+	{
+	  kind = kind * 10 + c - '0';
+	  if (kind > 9999999)
+	    goto no_match;
+	  c = gfc_next_char ();
+	}
+
+    }
+  else
+    {
+      gfc_current_locus = old_locus;
+
+      m = match_charkind_name (name);
+      if (m != MATCH_YES)
+	goto no_match;
+
+      if (gfc_find_symbol (name, NULL, 1, &sym)
+	  || sym == NULL
+	  || sym->attr.flavor != FL_PARAMETER)
+	goto no_match;
+
+      kind = -1;
+      c = gfc_next_char ();
+    }
+
+  if (c == ' ')
+    {
+      gfc_gobble_whitespace ();
+      c = gfc_next_char ();
+    }
+
+  if (c != '_')
+    goto no_match;
+
+  gfc_gobble_whitespace ();
+
+  c = gfc_next_char ();
+  if (c != '\'' && c != '"')
+    goto no_match;
+
+  start_locus = gfc_current_locus;
+
+  if (kind == -1)
+    {
+      q = gfc_extract_int (sym->value, &kind);
+      if (q != NULL)
+	{
+	  gfc_error (q);
+	  return MATCH_ERROR;
+	}
+      gfc_set_sym_referenced (sym);
+    }
+
+  if (gfc_validate_kind (BT_CHARACTER, kind, true) < 0)
+    {
+      gfc_error ("Invalid kind %d for CHARACTER constant at %C", kind);
+      return MATCH_ERROR;
+    }
+
+got_delim:
+  /* Scan the string into a block of memory by first figuring out how
+     long it is, allocating the structure, then re-reading it.  This
+     isn't particularly efficient, but string constants aren't that
+     common in most code.  TODO: Use obstacks?  */
+
+  delimiter = c;
+  length = 0;
+
+  for (;;)
+    {
+      c = next_string_char (delimiter, &ret);
+      if (ret == -1)
+	break;
+      if (ret == -2)
+	{
+	  gfc_current_locus = start_locus;
+	  gfc_error ("Unterminated character constant beginning at %C");
+	  return MATCH_ERROR;
+	}
+
+      length++;
+    }
+
+  /* Peek at the next character to see if it is a b, o, z, or x for the
+     postfixed BOZ literal constants.  */
+  peek = gfc_peek_ascii_char ();
+  if (peek == 'b' || peek == 'o' || peek =='z' || peek == 'x')
+    goto no_match;
+
+  e = gfc_get_character_expr (kind, &start_locus, NULL, length);
+
+  gfc_current_locus = start_locus;
+
+  /* We disable the warning for the following loop as the warning has already
+     been printed in the loop above.  */
+  warn_ampersand = gfc_option.warn_ampersand;
+  gfc_option.warn_ampersand = 0;
+
+  p = e->value.character.string;
+  for (i = 0; i < length; i++)
+    {
+      c = next_string_char (delimiter, &ret);
+
+      if (!gfc_check_character_range (c, kind))
+	{
+	  gfc_free_expr (e);
+	  gfc_error ("Character '%s' in string at %C is not representable "
+		     "in character kind %d", gfc_print_wide_char (c), kind);
+	  return MATCH_ERROR;
+	}
+
+      *p++ = c;
+    }
+
+  *p = '\0';	/* TODO: C-style string is for development/debug purposes.  */
+  gfc_option.warn_ampersand = warn_ampersand;
+
+  next_string_char (delimiter, &ret);
+  if (ret != -1)
+    gfc_internal_error ("match_string_constant(): Delimiter not found");
+
+  if (match_substring (NULL, 0, &e->ref) != MATCH_NO)
+    e->expr_type = EXPR_SUBSTRING;
+
+  *result = e;
+
+  return MATCH_YES;
+
+no_match:
+  gfc_current_locus = old_locus;
+  return MATCH_NO;
+}
+
+
+/* Match a .true. or .false.  Returns 1 if a .true. was found,
+   0 if a .false. was found, and -1 otherwise.  */
+static int
+match_logical_constant_string (void)
+{
+  locus orig_loc = gfc_current_locus;
+
+  gfc_gobble_whitespace ();
+  if (gfc_next_ascii_char () == '.')
+    {
+      char ch = gfc_next_ascii_char ();
+      if (ch == 'f')
+	{
+	  if (gfc_next_ascii_char () == 'a'
+	      && gfc_next_ascii_char () == 'l'
+	      && gfc_next_ascii_char () == 's'
+	      && gfc_next_ascii_char () == 'e'
+	      && gfc_next_ascii_char () == '.')
+	    /* Matched ".false.".  */
+	    return 0;
+	}
+      else if (ch == 't')
+	{
+	  if (gfc_next_ascii_char () == 'r'
+	      && gfc_next_ascii_char () == 'u'
+	      && gfc_next_ascii_char () == 'e'
+	      && gfc_next_ascii_char () == '.')
+	    /* Matched ".true.".  */
+	    return 1;
+	}
+    }
+  gfc_current_locus = orig_loc;
+  return -1;
+}
+
+/* Match a .true. or .false.  */
+
+static match
+match_logical_constant (gfc_expr **result)
+{
+  gfc_expr *e;
+  int i, kind, is_iso_c;
+
+  i = match_logical_constant_string ();
+  if (i == -1)
+    return MATCH_NO;
+
+  kind = get_kind (&is_iso_c);
+  if (kind == -1)
+    return MATCH_ERROR;
+  if (kind == -2)
+    kind = gfc_default_logical_kind;
+
+  if (gfc_validate_kind (BT_LOGICAL, kind, true) < 0)
+    {
+      gfc_error ("Bad kind for logical constant at %C");
+      return MATCH_ERROR;
+    }
+
+  e = gfc_get_logical_expr (kind, &gfc_current_locus, i);
+  e->ts.is_c_interop = is_iso_c;
+
+  *result = e;
+  return MATCH_YES;
+}
+
+
+/* Match a real or imaginary part of a complex constant that is a
+   symbolic constant.  */
+
+static match
+match_sym_complex_part (gfc_expr **result)
+{
+  char name[GFC_MAX_SYMBOL_LEN + 1];
+  gfc_symbol *sym;
+  gfc_expr *e;
+  match m;
+
+  m = gfc_match_name (name);
+  if (m != MATCH_YES)
+    return m;
+
+  if (gfc_find_symbol (name, NULL, 1, &sym) || sym == NULL)
+    return MATCH_NO;
+
+  if (sym->attr.flavor != FL_PARAMETER)
+    {
+      gfc_error ("Expected PARAMETER symbol in complex constant at %C");
+      return MATCH_ERROR;
+    }
+
+  if (!gfc_numeric_ts (&sym->value->ts))
+    {
+      gfc_error ("Numeric PARAMETER required in complex constant at %C");
+      return MATCH_ERROR;
+    }
+
+  if (sym->value->rank != 0)
+    {
+      gfc_error ("Scalar PARAMETER required in complex constant at %C");
+      return MATCH_ERROR;
+    }
+
+  if (!gfc_notify_std (GFC_STD_F2003, "PARAMETER symbol in "
+		       "complex constant at %C"))
+    return MATCH_ERROR;
+
+  switch (sym->value->ts.type)
+    {
+    case BT_REAL:
+      e = gfc_copy_expr (sym->value);
+      break;
+
+    case BT_COMPLEX:
+      e = gfc_complex2real (sym->value, sym->value->ts.kind);
+      if (e == NULL)
+	goto error;
+      break;
+
+    case BT_INTEGER:
+      e = gfc_int2real (sym->value, gfc_default_real_kind);
+      if (e == NULL)
+	goto error;
+      break;
+
+    default:
+      gfc_internal_error ("gfc_match_sym_complex_part(): Bad type");
+    }
+
+  *result = e;		/* e is a scalar, real, constant expression.  */
+  return MATCH_YES;
+
+error:
+  gfc_error ("Error converting PARAMETER constant in complex constant at %C");
+  return MATCH_ERROR;
+}
+
+
+/* Match a real or imaginary part of a complex number.  */
+
+static match
+match_complex_part (gfc_expr **result)
+{
+  match m;
+
+  m = match_sym_complex_part (result);
+  if (m != MATCH_NO)
+    return m;
+
+  m = match_real_constant (result, 1);
+  if (m != MATCH_NO)
+    return m;
+
+  return match_integer_constant (result, 1);
+}
+
+
+/* Try to match a complex constant.  */
+
+static match
+match_complex_constant (gfc_expr **result)
+{
+  gfc_expr *e, *real, *imag;
+  gfc_error_buf old_error;
+  gfc_typespec target;
+  locus old_loc;
+  int kind;
+  match m;
+
+  old_loc = gfc_current_locus;
+  real = imag = e = NULL;
+
+  m = gfc_match_char ('(');
+  if (m != MATCH_YES)
+    return m;
+
+  gfc_push_error (&old_error);
+
+  m = match_complex_part (&real);
+  if (m == MATCH_NO)
+    {
+      gfc_free_error (&old_error);
+      goto cleanup;
+    }
+
+  if (gfc_match_char (',') == MATCH_NO)
+    {
+      gfc_pop_error (&old_error);
+      m = MATCH_NO;
+      goto cleanup;
+    }
+
+  /* If m is error, then something was wrong with the real part and we
+     assume we have a complex constant because we've seen the ','.  An
+     ambiguous case here is the start of an iterator list of some
+     sort. These sort of lists are matched prior to coming here.  */
+
+  if (m == MATCH_ERROR)
+    {
+      gfc_free_error (&old_error);
+      goto cleanup;
+    }
+  gfc_pop_error (&old_error);
+
+  m = match_complex_part (&imag);
+  if (m == MATCH_NO)
+    goto syntax;
+  if (m == MATCH_ERROR)
+    goto cleanup;
+
+  m = gfc_match_char (')');
+  if (m == MATCH_NO)
+    {
+      /* Give the matcher for implied do-loops a chance to run.  This
+	 yields a much saner error message for (/ (i, 4=i, 6) /).  */
+      if (gfc_peek_ascii_char () == '=')
+	{
+	  m = MATCH_ERROR;
+	  goto cleanup;
+	}
+      else
+    goto syntax;
+    }
+
+  if (m == MATCH_ERROR)
+    goto cleanup;
+
+  /* Decide on the kind of this complex number.  */
+  if (real->ts.type == BT_REAL)
+    {
+      if (imag->ts.type == BT_REAL)
+	kind = gfc_kind_max (real, imag);
+      else
+	kind = real->ts.kind;
+    }
+  else
+    {
+      if (imag->ts.type == BT_REAL)
+	kind = imag->ts.kind;
+      else
+	kind = gfc_default_real_kind;
+    }
+  gfc_clear_ts (&target);
+  target.type = BT_REAL;
+  target.kind = kind;
+
+  if (real->ts.type != BT_REAL || kind != real->ts.kind)
+    gfc_convert_type (real, &target, 2);
+  if (imag->ts.type != BT_REAL || kind != imag->ts.kind)
+    gfc_convert_type (imag, &target, 2);
+
+  e = gfc_convert_complex (real, imag, kind);
+  e->where = gfc_current_locus;
+
+  gfc_free_expr (real);
+  gfc_free_expr (imag);
+
+  *result = e;
+  return MATCH_YES;
+
+syntax:
+  gfc_error ("Syntax error in COMPLEX constant at %C");
+  m = MATCH_ERROR;
+
+cleanup:
+  gfc_free_expr (e);
+  gfc_free_expr (real);
+  gfc_free_expr (imag);
+  gfc_current_locus = old_loc;
+
+  return m;
+}
+
+
+/* Match constants in any of several forms.  Returns nonzero for a
+   match, zero for no match.  */
+
+match
+gfc_match_literal_constant (gfc_expr **result, int signflag)
+{
+  match m;
+
+  m = match_complex_constant (result);
+  if (m != MATCH_NO)
+    return m;
+
+  m = match_string_constant (result);
+  if (m != MATCH_NO)
+    return m;
+
+  m = match_boz_constant (result);
+  if (m != MATCH_NO)
+    return m;
+
+  m = match_real_constant (result, signflag);
+  if (m != MATCH_NO)
+    return m;
+
+  m = match_hollerith_constant (result);
+  if (m != MATCH_NO)
+    return m;
+
+  m = match_integer_constant (result, signflag);
+  if (m != MATCH_NO)
+    return m;
+
+  m = match_logical_constant (result);
+  if (m != MATCH_NO)
+    return m;
+
+  return MATCH_NO;
+}
+
+
+/* This checks if a symbol is the return value of an encompassing function.
+   Function nesting can be maximally two levels deep, but we may have
+   additional local namespaces like BLOCK etc.  */
+
+bool
+gfc_is_function_return_value (gfc_symbol *sym, gfc_namespace *ns)
+{
+  if (!sym->attr.function || (sym->result != sym))
+    return false;
+  while (ns)
+    {
+      if (ns->proc_name == sym)
+	return true;
+      ns = ns->parent;
+    }
+  return false;
+}
+
+
+/* Match a single actual argument value.  An actual argument is
+   usually an expression, but can also be a procedure name.  If the
+   argument is a single name, it is not always possible to tell
+   whether the name is a dummy procedure or not.  We treat these cases
+   by creating an argument that looks like a dummy procedure and
+   fixing things later during resolution.  */
+
+static match
+match_actual_arg (gfc_expr **result)
+{
+  char name[GFC_MAX_SYMBOL_LEN + 1];
+  gfc_symtree *symtree;
+  locus where, w;
+  gfc_expr *e;
+  char c;
+
+  gfc_gobble_whitespace ();
+  where = gfc_current_locus;
+
+  switch (gfc_match_name (name))
+    {
+    case MATCH_ERROR:
+      return MATCH_ERROR;
+
+    case MATCH_NO:
+      break;
+
+    case MATCH_YES:
+      w = gfc_current_locus;
+      gfc_gobble_whitespace ();
+      c = gfc_next_ascii_char ();
+      gfc_current_locus = w;
+
+      if (c != ',' && c != ')')
+	break;
+
+      if (gfc_find_sym_tree (name, NULL, 1, &symtree))
+	break;
+      /* Handle error elsewhere.  */
+
+      /* Eliminate a couple of common cases where we know we don't
+	 have a function argument.  */
+      if (symtree == NULL)
+	{
+	  gfc_get_sym_tree (name, NULL, &symtree, false);
+	  gfc_set_sym_referenced (symtree->n.sym);
+	}
+      else
+	{
+	  gfc_symbol *sym;
+
+	  sym = symtree->n.sym;
+	  gfc_set_sym_referenced (sym);
+	  if (sym->attr.flavor != FL_PROCEDURE
+	      && sym->attr.flavor != FL_UNKNOWN)
+	    break;
+
+	  if (sym->attr.in_common && !sym->attr.proc_pointer)
+	    {
+	      if (!gfc_add_flavor (&sym->attr, FL_VARIABLE, 
+				   sym->name, &sym->declared_at))
+		return MATCH_ERROR;
+	      break;
+	    }
+
+	  /* If the symbol is a function with itself as the result and
+	     is being defined, then we have a variable.  */
+	  if (sym->attr.function && sym->result == sym)
+	    {
+	      if (gfc_is_function_return_value (sym, gfc_current_ns))
+		break;
+
+	      if (sym->attr.entry
+		  && (sym->ns == gfc_current_ns
+		      || sym->ns == gfc_current_ns->parent))
+		{
+		  gfc_entry_list *el = NULL;
+
+		  for (el = sym->ns->entries; el; el = el->next)
+		    if (sym == el->sym)
+		      break;
+
+		  if (el)
+		    break;
+		}
+	    }
+	}
+
+      e = gfc_get_expr ();	/* Leave it unknown for now */
+      e->symtree = symtree;
+      e->expr_type = EXPR_VARIABLE;
+      e->ts.type = BT_PROCEDURE;
+      e->where = where;
+
+      *result = e;
+      return MATCH_YES;
+    }
+
+  gfc_current_locus = where;
+  return gfc_match_expr (result);
+}
+
+
+/* Match a keyword argument.  */
+
+static match
+match_keyword_arg (gfc_actual_arglist *actual, gfc_actual_arglist *base)
+{
+  char name[GFC_MAX_SYMBOL_LEN + 1];
+  gfc_actual_arglist *a;
+  locus name_locus;
+  match m;
+
+  name_locus = gfc_current_locus;
+  m = gfc_match_name (name);
+
+  if (m != MATCH_YES)
+    goto cleanup;
+  if (gfc_match_char ('=') != MATCH_YES)
+    {
+      m = MATCH_NO;
+      goto cleanup;
+    }
+
+  m = match_actual_arg (&actual->expr);
+  if (m != MATCH_YES)
+    goto cleanup;
+
+  /* Make sure this name has not appeared yet.  */
+
+  if (name[0] != '\0')
+    {
+      for (a = base; a; a = a->next)
+	if (a->name != NULL && strcmp (a->name, name) == 0)
+	  {
+	    gfc_error ("Keyword '%s' at %C has already appeared in the "
+		       "current argument list", name);
+	    return MATCH_ERROR;
+	  }
+    }
+
+  actual->name = gfc_get_string (name);
+  return MATCH_YES;
+
+cleanup:
+  gfc_current_locus = name_locus;
+  return m;
+}
+
+
+/* Match an argument list function, such as %VAL.  */
+
+static match
+match_arg_list_function (gfc_actual_arglist *result)
+{
+  char name[GFC_MAX_SYMBOL_LEN + 1];
+  locus old_locus;
+  match m;
+
+  old_locus = gfc_current_locus;
+
+  if (gfc_match_char ('%') != MATCH_YES)
+    {
+      m = MATCH_NO;
+      goto cleanup;
+    }
+
+  m = gfc_match ("%n (", name);
+  if (m != MATCH_YES)
+    goto cleanup;
+
+  if (name[0] != '\0')
+    {
+      switch (name[0])
+	{
+	case 'l':
+	  if (strncmp (name, "loc", 3) == 0)
+	    {
+	      result->name = "%LOC";
+	      break;
+	    }
+	case 'r':
+	  if (strncmp (name, "ref", 3) == 0)
+	    {
+	      result->name = "%REF";
+	      break;
+	    }
+	case 'v':
+	  if (strncmp (name, "val", 3) == 0)
+	    {
+	      result->name = "%VAL";
+	      break;
+	    }
+	default:
+	  m = MATCH_ERROR;
+	  goto cleanup;
+	}
+    }
+
+  if (!gfc_notify_std (GFC_STD_GNU, "argument list function at %C"))
+    {
+      m = MATCH_ERROR;
+      goto cleanup;
+    }
+
+  m = match_actual_arg (&result->expr);
+  if (m != MATCH_YES)
+    goto cleanup;
+
+  if (gfc_match_char (')') != MATCH_YES)
+    {
+      m = MATCH_NO;
+      goto cleanup;
+    }
+
+  return MATCH_YES;
+
+cleanup:
+  gfc_current_locus = old_locus;
+  return m;
+}
+
+
+/* Matches an actual argument list of a function or subroutine, from
+   the opening parenthesis to the closing parenthesis.  The argument
+   list is assumed to allow keyword arguments because we don't know if
+   the symbol associated with the procedure has an implicit interface
+   or not.  We make sure keywords are unique. If sub_flag is set,
+   we're matching the argument list of a subroutine.  */
+
+match
+gfc_match_actual_arglist (int sub_flag, gfc_actual_arglist **argp)
+{
+  gfc_actual_arglist *head, *tail;
+  int seen_keyword;
+  gfc_st_label *label;
+  locus old_loc;
+  match m;
+
+  *argp = tail = NULL;
+  old_loc = gfc_current_locus;
+
+  seen_keyword = 0;
+
+  if (gfc_match_char ('(') == MATCH_NO)
+    return (sub_flag) ? MATCH_YES : MATCH_NO;
+
+  if (gfc_match_char (')') == MATCH_YES)
+    return MATCH_YES;
+  head = NULL;
+
+  matching_actual_arglist++;
+
+  for (;;)
+    {
+      if (head == NULL)
+	head = tail = gfc_get_actual_arglist ();
+      else
+	{
+	  tail->next = gfc_get_actual_arglist ();
+	  tail = tail->next;
+	}
+
+      if (sub_flag && gfc_match_char ('*') == MATCH_YES)
+	{
+	  m = gfc_match_st_label (&label);
+	  if (m == MATCH_NO)
+	    gfc_error ("Expected alternate return label at %C");
+	  if (m != MATCH_YES)
+	    goto cleanup;
+
+	  if (!gfc_notify_std (GFC_STD_F95_OBS, "Alternate-return argument "
+			       "at %C"))
+	    goto cleanup;
+
+	  tail->label = label;
+	  goto next;
+	}
+
+      /* After the first keyword argument is seen, the following
+	 arguments must also have keywords.  */
+      if (seen_keyword)
+	{
+	  m = match_keyword_arg (tail, head);
+
+	  if (m == MATCH_ERROR)
+	    goto cleanup;
+	  if (m == MATCH_NO)
+	    {
+	      gfc_error ("Missing keyword name in actual argument list at %C");
+	      goto cleanup;
+	    }
+
+	}
+      else
+	{
+	  /* Try an argument list function, like %VAL.  */
+	  m = match_arg_list_function (tail);
+	  if (m == MATCH_ERROR)
+	    goto cleanup;
+
+	  /* See if we have the first keyword argument.  */
+	  if (m == MATCH_NO)
+	    {
+	      m = match_keyword_arg (tail, head);
+	      if (m == MATCH_YES)
+		seen_keyword = 1;
+	      if (m == MATCH_ERROR)
+		goto cleanup;
+	    }
+
+	  if (m == MATCH_NO)
+	    {
+	      /* Try for a non-keyword argument.  */
+	      m = match_actual_arg (&tail->expr);
+	      if (m == MATCH_ERROR)
+		goto cleanup;
+	      if (m == MATCH_NO)
+		goto syntax;
+	    }
+	}
+
+
+    next:
+      if (gfc_match_char (')') == MATCH_YES)
+	break;
+      if (gfc_match_char (',') != MATCH_YES)
+	goto syntax;
+    }
+
+  *argp = head;
+  matching_actual_arglist--;
+  return MATCH_YES;
+
+syntax:
+  gfc_error ("Syntax error in argument list at %C");
+
+cleanup:
+  gfc_free_actual_arglist (head);
+  gfc_current_locus = old_loc;
+  matching_actual_arglist--;
+  return MATCH_ERROR;
+}
+
+
+/* Used by gfc_match_varspec() to extend the reference list by one
+   element.  */
+
+static gfc_ref *
+extend_ref (gfc_expr *primary, gfc_ref *tail)
+{
+  if (primary->ref == NULL)
+    primary->ref = tail = gfc_get_ref ();
+  else
+    {
+      if (tail == NULL)
+	gfc_internal_error ("extend_ref(): Bad tail");
+      tail->next = gfc_get_ref ();
+      tail = tail->next;
+    }
+
+  return tail;
+}
+
+
+/* Match any additional specifications associated with the current
+   variable like member references or substrings.  If equiv_flag is
+   set we only match stuff that is allowed inside an EQUIVALENCE
+   statement.  sub_flag tells whether we expect a type-bound procedure found
+   to be a subroutine as part of CALL or a FUNCTION. For procedure pointer
+   components, 'ppc_arg' determines whether the PPC may be called (with an
+   argument list), or whether it may just be referred to as a pointer.  */
+
+match
+gfc_match_varspec (gfc_expr *primary, int equiv_flag, bool sub_flag,
+		   bool ppc_arg)
+{
+  char name[GFC_MAX_SYMBOL_LEN + 1];
+  gfc_ref *substring, *tail;
+  gfc_component *component;
+  gfc_symbol *sym = primary->symtree->n.sym;
+  match m;
+  bool unknown;
+
+  tail = NULL;
+
+  gfc_gobble_whitespace ();
+
+  if (gfc_peek_ascii_char () == '[')
+    {
+      if ((sym->ts.type != BT_CLASS && sym->attr.dimension)
+	  || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
+	      && CLASS_DATA (sym)->attr.dimension))
+	{
+	  gfc_error ("Array section designator, e.g. '(:)', is required "
+		     "besides the coarray designator '[...]' at %C");
+	  return MATCH_ERROR;
+	}
+      if ((sym->ts.type != BT_CLASS && !sym->attr.codimension)
+	  || (sym->ts.type == BT_CLASS && CLASS_DATA (sym)
+	      && !CLASS_DATA (sym)->attr.codimension))
+	{
+	  gfc_error ("Coarray designator at %C but '%s' is not a coarray",
+		     sym->name);
+	  return MATCH_ERROR;
+	}
+    }
+
+  /* For associate names, we may not yet know whether they are arrays or not.
+     Thus if we have one and parentheses follow, we have to assume that it
+     actually is one for now.  The final decision will be made at
+     resolution time, of course.  */
+  if (sym->assoc && gfc_peek_ascii_char () == '(')
+    sym->attr.dimension = 1;
+
+  if ((equiv_flag && gfc_peek_ascii_char () == '(')
+      || gfc_peek_ascii_char () == '[' || sym->attr.codimension
+      || (sym->attr.dimension && sym->ts.type != BT_CLASS
+	  && !sym->attr.proc_pointer && !gfc_is_proc_ptr_comp (primary)
+	  && !(gfc_matching_procptr_assignment
+	       && sym->attr.flavor == FL_PROCEDURE))
+      || (sym->ts.type == BT_CLASS && sym->attr.class_ok
+	  && (CLASS_DATA (sym)->attr.dimension
+	      || CLASS_DATA (sym)->attr.codimension)))
+    {
+      gfc_array_spec *as;
+
+      tail = extend_ref (primary, tail);
+      tail->type = REF_ARRAY;
+
+      /* In EQUIVALENCE, we don't know yet whether we are seeing
+	 an array, character variable or array of character
+	 variables.  We'll leave the decision till resolve time.  */
+
+      if (equiv_flag)
+	as = NULL;
+      else if (sym->ts.type == BT_CLASS && CLASS_DATA (sym))
+	as = CLASS_DATA (sym)->as;
+      else
+	as = sym->as;
+
+      m = gfc_match_array_ref (&tail->u.ar, as, equiv_flag,
+			       as ? as->corank : 0);
+      if (m != MATCH_YES)
+	return m;
+
+      gfc_gobble_whitespace ();
+      if (equiv_flag && gfc_peek_ascii_char () == '(')
+	{
+	  tail = extend_ref (primary, tail);
+	  tail->type = REF_ARRAY;
+
+	  m = gfc_match_array_ref (&tail->u.ar, NULL, equiv_flag, 0);
+	  if (m != MATCH_YES)
+	    return m;
+	}
+    }
+
+  primary->ts = sym->ts;
+
+  if (equiv_flag)
+    return MATCH_YES;
+
+  if (sym->ts.type == BT_UNKNOWN && gfc_peek_ascii_char () == '%'
+      && gfc_get_default_type (sym->name, sym->ns)->type == BT_DERIVED)
+    gfc_set_default_type (sym, 0, sym->ns);
+
+  if (sym->ts.type == BT_UNKNOWN && gfc_match_char ('%') == MATCH_YES)
+    {
+      gfc_error ("Symbol '%s' at %C has no IMPLICIT type", sym->name);
+      return MATCH_ERROR;
+    }
+  else if ((sym->ts.type != BT_DERIVED && sym->ts.type != BT_CLASS)
+	   && gfc_match_char ('%') == MATCH_YES)
+    {
+      gfc_error ("Unexpected '%%' for nonderived-type variable '%s' at %C",
+		 sym->name);
+      return MATCH_ERROR;
+    }
+
+  if ((sym->ts.type != BT_DERIVED && sym->ts.type != BT_CLASS)
+      || gfc_match_char ('%') != MATCH_YES)
+    goto check_substring;
+
+  sym = sym->ts.u.derived;
+
+  for (;;)
+    {
+      bool t;
+      gfc_symtree *tbp;
+
+      m = gfc_match_name (name);
+      if (m == MATCH_NO)
+	gfc_error ("Expected structure component name at %C");
+      if (m != MATCH_YES)
+	return MATCH_ERROR;
+
+      if (sym->f2k_derived)
+	tbp = gfc_find_typebound_proc (sym, &t, name, false, &gfc_current_locus);
+      else
+	tbp = NULL;
+
+      if (tbp)
+	{
+	  gfc_symbol* tbp_sym;
+
+	  if (!t)
+	    return MATCH_ERROR;
+
+	  gcc_assert (!tail || !tail->next);
+
+	  if (!(primary->expr_type == EXPR_VARIABLE
+		|| (primary->expr_type == EXPR_STRUCTURE
+		    && primary->symtree && primary->symtree->n.sym
+		    && primary->symtree->n.sym->attr.flavor)))
+	    return MATCH_ERROR;
+
+	  if (tbp->n.tb->is_generic)
+	    tbp_sym = NULL;
+	  else
+	    tbp_sym = tbp->n.tb->u.specific->n.sym;
+
+	  primary->expr_type = EXPR_COMPCALL;
+	  primary->value.compcall.tbp = tbp->n.tb;
+	  primary->value.compcall.name = tbp->name;
+	  primary->value.compcall.ignore_pass = 0;
+	  primary->value.compcall.assign = 0;
+	  primary->value.compcall.base_object = NULL;
+	  gcc_assert (primary->symtree->n.sym->attr.referenced);
+	  if (tbp_sym)
+	    primary->ts = tbp_sym->ts;
+	  else
+	    gfc_clear_ts (&primary->ts);
+
+	  m = gfc_match_actual_arglist (tbp->n.tb->subroutine,
+					&primary->value.compcall.actual);
+	  if (m == MATCH_ERROR)
+	    return MATCH_ERROR;
+	  if (m == MATCH_NO)
+	    {
+	      if (sub_flag)
+		primary->value.compcall.actual = NULL;
+	      else
+		{
+		  gfc_error ("Expected argument list at %C");
+		  return MATCH_ERROR;
+		}
+	    }
+
+	  break;
+	}
+
+      component = gfc_find_component (sym, name, false, false);
+      if (component == NULL)
+	return MATCH_ERROR;
+
+      tail = extend_ref (primary, tail);
+      tail->type = REF_COMPONENT;
+
+      tail->u.c.component = component;
+      tail->u.c.sym = sym;
+
+      primary->ts = component->ts;
+
+      if (component->attr.proc_pointer && ppc_arg)
+	{
+	  /* Procedure pointer component call: Look for argument list.  */
+	  m = gfc_match_actual_arglist (sub_flag,
+					&primary->value.compcall.actual);
+	  if (m == MATCH_ERROR)
+	    return MATCH_ERROR;
+
+	  if (m == MATCH_NO && !gfc_matching_ptr_assignment
+	      && !gfc_matching_procptr_assignment && !matching_actual_arglist)
+	    {
+	      gfc_error ("Procedure pointer component '%s' requires an "
+			 "argument list at %C", component->name);
+	      return MATCH_ERROR;
+	    }
+
+	  if (m == MATCH_YES)
+	    primary->expr_type = EXPR_PPC;
+
+          break;
+	}
+
+      if (component->as != NULL && !component->attr.proc_pointer)
+	{
+	  tail = extend_ref (primary, tail);
+	  tail->type = REF_ARRAY;
+
+	  m = gfc_match_array_ref (&tail->u.ar, component->as, equiv_flag,
+			  component->as->corank);
+	  if (m != MATCH_YES)
+	    return m;
+	}
+      else if (component->ts.type == BT_CLASS && component->attr.class_ok
+	       && CLASS_DATA (component)->as && !component->attr.proc_pointer)
+	{
+	  tail = extend_ref (primary, tail);
+	  tail->type = REF_ARRAY;
+
+	  m = gfc_match_array_ref (&tail->u.ar, CLASS_DATA (component)->as,
+				   equiv_flag,
+				   CLASS_DATA (component)->as->corank);
+	  if (m != MATCH_YES)
+	    return m;
+	}
+
+      if ((component->ts.type != BT_DERIVED && component->ts.type != BT_CLASS)
+	  || gfc_match_char ('%') != MATCH_YES)
+	break;
+
+      sym = component->ts.u.derived;
+    }
+
+check_substring:
+  unknown = false;
+  if (primary->ts.type == BT_UNKNOWN && sym->attr.flavor != FL_DERIVED)
+    {
+      if (gfc_get_default_type (sym->name, sym->ns)->type == BT_CHARACTER)
+       {
+	 gfc_set_default_type (sym, 0, sym->ns);
+	 primary->ts = sym->ts;
+	 unknown = true;
+       }
+    }
+
+  if (primary->ts.type == BT_CHARACTER)
+    {
+      switch (match_substring (primary->ts.u.cl, equiv_flag, &substring))
+	{
+	case MATCH_YES:
+	  if (tail == NULL)
+	    primary->ref = substring;
+	  else
+	    tail->next = substring;
+
+	  if (primary->expr_type == EXPR_CONSTANT)
+	    primary->expr_type = EXPR_SUBSTRING;
+
+	  if (substring)
+	    primary->ts.u.cl = NULL;
+
+	  break;
+
+	case MATCH_NO:
+	  if (unknown)
+	    {
+	      gfc_clear_ts (&primary->ts);
+	      gfc_clear_ts (&sym->ts);
+	    }
+	  break;
+
+	case MATCH_ERROR:
+	  return MATCH_ERROR;
+	}
+    }
+
+  /* F2008, C727.  */
+  if (primary->expr_type == EXPR_PPC && gfc_is_coindexed (primary))
+    {
+      gfc_error ("Coindexed procedure-pointer component at %C");
+      return MATCH_ERROR;
+    }
+
+  return MATCH_YES;
+}
+
+
+/* Given an expression that is a variable, figure out what the
+   ultimate variable's type and attribute is, traversing the reference
+   structures if necessary.
+
+   This subroutine is trickier than it looks.  We start at the base
+   symbol and store the attribute.  Component references load a
+   completely new attribute.
+
+   A couple of rules come into play.  Subobjects of targets are always
+   targets themselves.  If we see a component that goes through a
+   pointer, then the expression must also be a target, since the
+   pointer is associated with something (if it isn't core will soon be
+   dumped).  If we see a full part or section of an array, the
+   expression is also an array.
+
+   We can have at most one full array reference.  */
+
+symbol_attribute
+gfc_variable_attr (gfc_expr *expr, gfc_typespec *ts)
+{
+  int dimension, codimension, pointer, allocatable, target;
+  symbol_attribute attr;
+  gfc_ref *ref;
+  gfc_symbol *sym;
+  gfc_component *comp;
+
+  if (expr->expr_type != EXPR_VARIABLE && expr->expr_type != EXPR_FUNCTION)
+    gfc_internal_error ("gfc_variable_attr(): Expression isn't a variable");
+
+  sym = expr->symtree->n.sym;
+  attr = sym->attr;
+
+  if (sym->ts.type == BT_CLASS && sym->attr.class_ok)
+    {
+      dimension = CLASS_DATA (sym)->attr.dimension;
+      codimension = CLASS_DATA (sym)->attr.codimension;
+      pointer = CLASS_DATA (sym)->attr.class_pointer;
+      allocatable = CLASS_DATA (sym)->attr.allocatable;
+    }
+  else
+    {
+      dimension = attr.dimension;
+      codimension = attr.codimension;
+      pointer = attr.pointer;
+      allocatable = attr.allocatable;
+    }
+
+  target = attr.target;
+  if (pointer || attr.proc_pointer)
+    target = 1;
+
+  if (ts != NULL && expr->ts.type == BT_UNKNOWN)
+    *ts = sym->ts;
+
+  for (ref = expr->ref; ref; ref = ref->next)
+    switch (ref->type)
+      {
+      case REF_ARRAY:
+
+	switch (ref->u.ar.type)
+	  {
+	  case AR_FULL:
+	    dimension = 1;
+	    break;
+
+	  case AR_SECTION:
+	    allocatable = pointer = 0;
+	    dimension = 1;
+	    break;
+
+	  case AR_ELEMENT:
+	    /* Handle coarrays.  */
+	    if (ref->u.ar.dimen > 0)
+	      allocatable = pointer = 0;
+	    break;
+
+	  case AR_UNKNOWN:
+	    gfc_internal_error ("gfc_variable_attr(): Bad array reference");
+	  }
+
+	break;
+
+      case REF_COMPONENT:
+	comp = ref->u.c.component;
+	attr = comp->attr;
+	if (ts != NULL)
+	  {
+	    *ts = comp->ts;
+	    /* Don't set the string length if a substring reference
+	       follows.  */
+	    if (ts->type == BT_CHARACTER
+		&& ref->next && ref->next->type == REF_SUBSTRING)
+		ts->u.cl = NULL;
+	  }
+
+	if (comp->ts.type == BT_CLASS)
+	  {
+	    codimension = CLASS_DATA (comp)->attr.codimension;
+	    pointer = CLASS_DATA (comp)->attr.class_pointer;
+	    allocatable = CLASS_DATA (comp)->attr.allocatable;
+	  }
+	else
+	  {
+	    codimension = comp->attr.codimension;
+	    pointer = comp->attr.pointer;
+	    allocatable = comp->attr.allocatable;
+	  }
+	if (pointer || attr.proc_pointer)
+	  target = 1;
+
+	break;
+
+      case REF_SUBSTRING:
+	allocatable = pointer = 0;
+	break;
+      }
+
+  attr.dimension = dimension;
+  attr.codimension = codimension;
+  attr.pointer = pointer;
+  attr.allocatable = allocatable;
+  attr.target = target;
+  attr.save = sym->attr.save;
+
+  return attr;
+}
+
+
+/* Return the attribute from a general expression.  */
+
+symbol_attribute
+gfc_expr_attr (gfc_expr *e)
+{
+  symbol_attribute attr;
+
+  switch (e->expr_type)
+    {
+    case EXPR_VARIABLE:
+      attr = gfc_variable_attr (e, NULL);
+      break;
+
+    case EXPR_FUNCTION:
+      gfc_clear_attr (&attr);
+
+      if (e->value.function.esym && e->value.function.esym->result)
+	{
+	  gfc_symbol *sym = e->value.function.esym->result;
+	  attr = sym->attr;
+	  if (sym->ts.type == BT_CLASS)
+	    {
+	      attr.dimension = CLASS_DATA (sym)->attr.dimension;
+	      attr.pointer = CLASS_DATA (sym)->attr.class_pointer;
+	      attr.allocatable = CLASS_DATA (sym)->attr.allocatable;
+	    }
+	}
+      else
+	attr = gfc_variable_attr (e, NULL);
+
+      /* TODO: NULL() returns pointers.  May have to take care of this
+	 here.  */
+
+      break;
+
+    default:
+      gfc_clear_attr (&attr);
+      break;
+    }
+
+  return attr;
+}
+
+
+/* Match a structure constructor.  The initial symbol has already been
+   seen.  */
+
+typedef struct gfc_structure_ctor_component
+{
+  char* name;
+  gfc_expr* val;
+  locus where;
+  struct gfc_structure_ctor_component* next;
+}
+gfc_structure_ctor_component;
+
+#define gfc_get_structure_ctor_component() XCNEW (gfc_structure_ctor_component)
+
+static void
+gfc_free_structure_ctor_component (gfc_structure_ctor_component *comp)
+{
+  free (comp->name);
+  gfc_free_expr (comp->val);
+  free (comp);
+}
+
+
+/* Translate the component list into the actual constructor by sorting it in
+   the order required; this also checks along the way that each and every
+   component actually has an initializer and handles default initializers
+   for components without explicit value given.  */
+static bool
+build_actual_constructor (gfc_structure_ctor_component **comp_head,
+			  gfc_constructor_base *ctor_head, gfc_symbol *sym)
+{
+  gfc_structure_ctor_component *comp_iter;
+  gfc_component *comp;
+
+  for (comp = sym->components; comp; comp = comp->next)
+    {
+      gfc_structure_ctor_component **next_ptr;
+      gfc_expr *value = NULL;
+
+      /* Try to find the initializer for the current component by name.  */
+      next_ptr = comp_head;
+      for (comp_iter = *comp_head; comp_iter; comp_iter = comp_iter->next)
+	{
+	  if (!strcmp (comp_iter->name, comp->name))
+	    break;
+	  next_ptr = &comp_iter->next;
+	}
+
+      /* If an extension, try building the parent derived type by building
+	 a value expression for the parent derived type and calling self.  */
+      if (!comp_iter && comp == sym->components && sym->attr.extension)
+	{
+	  value = gfc_get_structure_constructor_expr (comp->ts.type,
+						      comp->ts.kind,
+						      &gfc_current_locus);
+	  value->ts = comp->ts;
+
+	  if (!build_actual_constructor (comp_head, 
+					 &value->value.constructor, 
+					 comp->ts.u.derived))
+	    {
+	      gfc_free_expr (value);
+	      return false;
+	    }
+
+	  gfc_constructor_append_expr (ctor_head, value, NULL);
+	  continue;
+	}
+
+      /* If it was not found, try the default initializer if there's any;
+	 otherwise, it's an error unless this is a deferred parameter.  */
+      if (!comp_iter)
+	{
+	  if (comp->initializer)
+	    {
+	      if (!gfc_notify_std (GFC_STD_F2003, "Structure constructor "
+				   "with missing optional arguments at %C"))
+		return false;
+	      value = gfc_copy_expr (comp->initializer);
+	    }
+	  else if (!comp->attr.deferred_parameter)
+	    {
+	      gfc_error ("No initializer for component '%s' given in the"
+			 " structure constructor at %C!", comp->name);
+	      return false;
+	    }
+	}
+      else
+	value = comp_iter->val;
+
+      /* Add the value to the constructor chain built.  */
+      gfc_constructor_append_expr (ctor_head, value, NULL);
+
+      /* Remove the entry from the component list.  We don't want the expression
+	 value to be free'd, so set it to NULL.  */
+      if (comp_iter)
+	{
+	  *next_ptr = comp_iter->next;
+	  comp_iter->val = NULL;
+	  gfc_free_structure_ctor_component (comp_iter);
+	}
+    }
+  return true;
+}
+
+
+bool
+gfc_convert_to_structure_constructor (gfc_expr *e, gfc_symbol *sym, gfc_expr **cexpr,
+				      gfc_actual_arglist **arglist,
+				      bool parent)
+{
+  gfc_actual_arglist *actual;
+  gfc_structure_ctor_component *comp_tail, *comp_head, *comp_iter;
+  gfc_constructor_base ctor_head = NULL;
+  gfc_component *comp; /* Is set NULL when named component is first seen */
+  const char* last_name = NULL;
+  locus old_locus;
+  gfc_expr *expr;
+
+  expr = parent ? *cexpr : e;
+  old_locus = gfc_current_locus;
+  if (parent)
+    ; /* gfc_current_locus = *arglist->expr ? ->where;*/
+  else
+    gfc_current_locus = expr->where;
+
+  comp_tail = comp_head = NULL;
+
+  if (!parent && sym->attr.abstract)
+    {
+      gfc_error ("Can't construct ABSTRACT type '%s' at %L",
+		 sym->name, &expr->where);
+      goto cleanup;
+    }
+
+  comp = sym->components;
+  actual = parent ? *arglist : expr->value.function.actual;
+  for ( ; actual; )
+    {
+      gfc_component *this_comp = NULL;
+
+      if (!comp_head)
+	comp_tail = comp_head = gfc_get_structure_ctor_component ();
+      else
+	{
+	  comp_tail->next = gfc_get_structure_ctor_component ();
+	  comp_tail = comp_tail->next;
+       	}
+      if (actual->name)
+	{
+	  if (!gfc_notify_std (GFC_STD_F2003, "Structure"
+			       " constructor with named arguments at %C"))
+	    goto cleanup;
+
+	  comp_tail->name = xstrdup (actual->name);
+	  last_name = comp_tail->name;
+	  comp = NULL;
+	}
+      else
+	{
+	  /* Components without name are not allowed after the first named
+	     component initializer!  */
+	  if (!comp || comp->attr.deferred_parameter)
+	    {
+	      if (last_name)
+		gfc_error ("Component initializer without name after component"
+			   " named %s at %L!", last_name,
+			   actual->expr ? &actual->expr->where
+					: &gfc_current_locus);
+	      else
+		gfc_error ("Too many components in structure constructor at "
+			   "%L!", actual->expr ? &actual->expr->where
+					       : &gfc_current_locus);
+	      goto cleanup;
+	    }
+
+	  comp_tail->name = xstrdup (comp->name);
+	}
+
+      /* Find the current component in the structure definition and check
+	     its access is not private.  */
+      if (comp)
+	this_comp = gfc_find_component (sym, comp->name, false, false);
+      else
+	{
+	  this_comp = gfc_find_component (sym, (const char *)comp_tail->name,
+					  false, false);
+	  comp = NULL; /* Reset needed!  */
+	}
+
+      /* Here we can check if a component name is given which does not
+	 correspond to any component of the defined structure.  */
+      if (!this_comp)
+	goto cleanup;
+
+      comp_tail->val = actual->expr;
+      if (actual->expr != NULL)
+	comp_tail->where = actual->expr->where;
+      actual->expr = NULL;
+
+      /* Check if this component is already given a value.  */
+      for (comp_iter = comp_head; comp_iter != comp_tail; 
+	   comp_iter = comp_iter->next)
+	{
+	  gcc_assert (comp_iter);
+	  if (!strcmp (comp_iter->name, comp_tail->name))
+	    {
+	      gfc_error ("Component '%s' is initialized twice in the structure"
+			 " constructor at %L!", comp_tail->name,
+			 comp_tail->val ? &comp_tail->where
+					: &gfc_current_locus);
+	      goto cleanup;
+	    }
+	}
+
+      /* F2008, R457/C725, for PURE C1283.  */
+      if (this_comp->attr.pointer && comp_tail->val
+	  && gfc_is_coindexed (comp_tail->val))
+     	{
+       	  gfc_error ("Coindexed expression to pointer component '%s' in "
+		     "structure constructor at %L!", comp_tail->name,
+		     &comp_tail->where);
+	  goto cleanup;
+	}
+
+          /* If not explicitly a parent constructor, gather up the components
+             and build one.  */
+          if (comp && comp == sym->components
+                && sym->attr.extension
+		&& comp_tail->val
+                && (comp_tail->val->ts.type != BT_DERIVED
+                      ||
+                    comp_tail->val->ts.u.derived != this_comp->ts.u.derived))
+            {
+              bool m;
+	      gfc_actual_arglist *arg_null = NULL;
+
+	      actual->expr = comp_tail->val;
+	      comp_tail->val = NULL;
+
+              m = gfc_convert_to_structure_constructor (NULL,
+					comp->ts.u.derived, &comp_tail->val,
+					comp->ts.u.derived->attr.zero_comp
+					  ? &arg_null : &actual, true);
+              if (!m)
+                goto cleanup;
+
+	      if (comp->ts.u.derived->attr.zero_comp)
+		{
+		  comp = comp->next;
+		  continue;
+		}
+            }
+
+      if (comp)
+	comp = comp->next;
+      if (parent && !comp)
+	break;
+
+      if (actual)
+	actual = actual->next;
+    }
+
+  if (!build_actual_constructor (&comp_head, &ctor_head, sym))
+    goto cleanup;
+
+  /* No component should be left, as this should have caused an error in the
+     loop constructing the component-list (name that does not correspond to any
+     component in the structure definition).  */
+  if (comp_head && sym->attr.extension)
+    {
+      for (comp_iter = comp_head; comp_iter; comp_iter = comp_iter->next)
+	{
+	  gfc_error ("component '%s' at %L has already been set by a "
+		     "parent derived type constructor", comp_iter->name,
+		     &comp_iter->where);
+	}
+      goto cleanup;
+    }
+  else
+    gcc_assert (!comp_head);
+
+  if (parent)
+    {
+      expr = gfc_get_structure_constructor_expr (BT_DERIVED, 0, &gfc_current_locus);
+      expr->ts.u.derived = sym;
+      expr->value.constructor = ctor_head;
+      *cexpr = expr;
+    }
+  else
+    {
+      expr->ts.u.derived = sym;
+      expr->ts.kind = 0;
+      expr->ts.type = BT_DERIVED;
+      expr->value.constructor = ctor_head;
+      expr->expr_type = EXPR_STRUCTURE;
+    }
+
+  gfc_current_locus = old_locus; 
+  if (parent)
+    *arglist = actual;
+  return true;
+
+  cleanup:
+  gfc_current_locus = old_locus; 
+
+  for (comp_iter = comp_head; comp_iter; )
+    {
+      gfc_structure_ctor_component *next = comp_iter->next;
+      gfc_free_structure_ctor_component (comp_iter);
+      comp_iter = next;
+    }
+  gfc_constructor_free (ctor_head);
+
+  return false;
+}
+
+
+match
+gfc_match_structure_constructor (gfc_symbol *sym, gfc_expr **result)
+{
+  match m;
+  gfc_expr *e;
+  gfc_symtree *symtree;
+
+  gfc_get_sym_tree (sym->name, NULL, &symtree, false);   /* Can't fail */
+
+  e = gfc_get_expr ();
+  e->symtree = symtree;
+  e->expr_type = EXPR_FUNCTION;
+
+  gcc_assert (sym->attr.flavor == FL_DERIVED
+	      && symtree->n.sym->attr.flavor == FL_PROCEDURE);
+  e->value.function.esym = sym;
+  e->symtree->n.sym->attr.generic = 1;
+
+   m = gfc_match_actual_arglist (0, &e->value.function.actual);
+   if (m != MATCH_YES)
+     {
+       gfc_free_expr (e);
+       return m;
+     }
+
+   if (!gfc_convert_to_structure_constructor (e, sym, NULL, NULL, false))
+     {
+       gfc_free_expr (e);
+       return MATCH_ERROR;
+     }
+
+   *result = e;
+   return MATCH_YES;
+}
+
+
+/* If the symbol is an implicit do loop index and implicitly typed,
+   it should not be host associated.  Provide a symtree from the
+   current namespace.  */
+static match
+check_for_implicit_index (gfc_symtree **st, gfc_symbol **sym)
+{
+  if ((*sym)->attr.flavor == FL_VARIABLE
+      && (*sym)->ns != gfc_current_ns
+      && (*sym)->attr.implied_index
+      && (*sym)->attr.implicit_type
+      && !(*sym)->attr.use_assoc)
+    {
+      int i;
+      i = gfc_get_sym_tree ((*sym)->name, NULL, st, false);
+      if (i)
+	return MATCH_ERROR;
+      *sym = (*st)->n.sym;
+    }
+  return MATCH_YES;
+}
+
+
+/* Procedure pointer as function result: Replace the function symbol by the
+   auto-generated hidden result variable named "ppr@".  */
+
+static bool
+replace_hidden_procptr_result (gfc_symbol **sym, gfc_symtree **st)
+{
+  /* Check for procedure pointer result variable.  */
+  if ((*sym)->attr.function && !(*sym)->attr.external
+      && (*sym)->result && (*sym)->result != *sym
+      && (*sym)->result->attr.proc_pointer
+      && (*sym) == gfc_current_ns->proc_name
+      && (*sym) == (*sym)->result->ns->proc_name
+      && strcmp ("ppr@", (*sym)->result->name) == 0)
+    {
+      /* Automatic replacement with "hidden" result variable.  */
+      (*sym)->result->attr.referenced = (*sym)->attr.referenced;
+      *sym = (*sym)->result;
+      *st = gfc_find_symtree ((*sym)->ns->sym_root, (*sym)->name);
+      return true;
+    }
+  return false;
+}
+
+
+/* Matches a variable name followed by anything that might follow it--
+   array reference, argument list of a function, etc.  */
+
+match
+gfc_match_rvalue (gfc_expr **result)
+{
+  gfc_actual_arglist *actual_arglist;
+  char name[GFC_MAX_SYMBOL_LEN + 1], argname[GFC_MAX_SYMBOL_LEN + 1];
+  gfc_state_data *st;
+  gfc_symbol *sym;
+  gfc_symtree *symtree;
+  locus where, old_loc;
+  gfc_expr *e;
+  match m, m2;
+  int i;
+  gfc_typespec *ts;
+  bool implicit_char;
+  gfc_ref *ref;
+
+  m = gfc_match_name (name);
+  if (m != MATCH_YES)
+    return m;
+
+  if (gfc_find_state (COMP_INTERFACE)
+      && !gfc_current_ns->has_import_set)
+    i = gfc_get_sym_tree (name, NULL, &symtree, false);
+  else
+    i = gfc_get_ha_sym_tree (name, &symtree);
+
+  if (i)
+    return MATCH_ERROR;
+
+  sym = symtree->n.sym;
+  e = NULL;
+  where = gfc_current_locus;
+
+  replace_hidden_procptr_result (&sym, &symtree);
+
+  /* If this is an implicit do loop index and implicitly typed,
+     it should not be host associated.  */
+  m = check_for_implicit_index (&symtree, &sym);
+  if (m != MATCH_YES)
+    return m;
+
+  gfc_set_sym_referenced (sym);
+  sym->attr.implied_index = 0;
+
+  if (sym->attr.function && sym->result == sym)
+    {
+      /* See if this is a directly recursive function call.  */
+      gfc_gobble_whitespace ();
+      if (sym->attr.recursive
+	  && gfc_peek_ascii_char () == '('
+	  && gfc_current_ns->proc_name == sym
+	  && !sym->attr.dimension)
+	{
+	  gfc_error ("'%s' at %C is the name of a recursive function "
+		     "and so refers to the result variable. Use an "
+		     "explicit RESULT variable for direct recursion "
+		     "(12.5.2.1)", sym->name);
+	  return MATCH_ERROR;
+	}
+
+      if (gfc_is_function_return_value (sym, gfc_current_ns))
+	goto variable;
+
+      if (sym->attr.entry
+	  && (sym->ns == gfc_current_ns
+	      || sym->ns == gfc_current_ns->parent))
+	{
+	  gfc_entry_list *el = NULL;
+	  
+	  for (el = sym->ns->entries; el; el = el->next)
+	    if (sym == el->sym)
+	      goto variable;
+	}
+    }
+
+  if (gfc_matching_procptr_assignment)
+    goto procptr0;
+
+  if (sym->attr.function || sym->attr.external || sym->attr.intrinsic)
+    goto function0;
+
+  if (sym->attr.generic)
+    goto generic_function;
+
+  switch (sym->attr.flavor)
+    {
+    case FL_VARIABLE:
+    variable:
+      e = gfc_get_expr ();
+
+      e->expr_type = EXPR_VARIABLE;
+      e->symtree = symtree;
+
+      m = gfc_match_varspec (e, 0, false, true);
+      break;
+
+    case FL_PARAMETER:
+      /* A statement of the form "REAL, parameter :: a(0:10) = 1" will
+	 end up here.  Unfortunately, sym->value->expr_type is set to 
+	 EXPR_CONSTANT, and so the if () branch would be followed without
+	 the !sym->as check.  */
+      if (sym->value && sym->value->expr_type != EXPR_ARRAY && !sym->as)
+	e = gfc_copy_expr (sym->value);
+      else
+	{
+	  e = gfc_get_expr ();
+	  e->expr_type = EXPR_VARIABLE;
+	}
+
+      e->symtree = symtree;
+      m = gfc_match_varspec (e, 0, false, true);
+
+      if (sym->ts.is_c_interop || sym->ts.is_iso_c)
+	break;
+
+      /* Variable array references to derived type parameters cause
+	 all sorts of headaches in simplification. Treating such
+	 expressions as variable works just fine for all array
+	 references.  */
+      if (sym->value && sym->ts.type == BT_DERIVED && e->ref)
+	{
+	  for (ref = e->ref; ref; ref = ref->next)
+	    if (ref->type == REF_ARRAY)
+	      break;
+
+	  if (ref == NULL || ref->u.ar.type == AR_FULL)
+	    break;
+
+	  ref = e->ref;
+	  e->ref = NULL;
+	  gfc_free_expr (e);
+	  e = gfc_get_expr ();
+	  e->expr_type = EXPR_VARIABLE;
+	  e->symtree = symtree;
+	  e->ref = ref;
+	}
+
+      break;
+
+    case FL_DERIVED:
+      sym = gfc_use_derived (sym);
+      if (sym == NULL)
+	m = MATCH_ERROR;
+      else
+	goto generic_function;
+      break;
+
+    /* If we're here, then the name is known to be the name of a
+       procedure, yet it is not sure to be the name of a function.  */
+    case FL_PROCEDURE:
+
+    /* Procedure Pointer Assignments. */
+    procptr0:
+      if (gfc_matching_procptr_assignment)
+	{
+	  gfc_gobble_whitespace ();
+	  if (!sym->attr.dimension && gfc_peek_ascii_char () == '(')
+	    /* Parse functions returning a procptr.  */
+	    goto function0;
+
+	  e = gfc_get_expr ();
+	  e->expr_type = EXPR_VARIABLE;
+	  e->symtree = symtree;
+	  m = gfc_match_varspec (e, 0, false, true);
+	  if (!e->ref && sym->attr.flavor == FL_UNKNOWN
+	      && sym->ts.type == BT_UNKNOWN
+	      && !gfc_add_flavor (&sym->attr, FL_PROCEDURE, sym->name, NULL))
+	    {
+	      m = MATCH_ERROR;
+	      break;
+	    }
+	  break;
+	}
+
+      if (sym->attr.subroutine)
+	{
+	  gfc_error ("Unexpected use of subroutine name '%s' at %C",
+		     sym->name);
+	  m = MATCH_ERROR;
+	  break;
+	}
+
+      /* At this point, the name has to be a non-statement function.
+	 If the name is the same as the current function being
+	 compiled, then we have a variable reference (to the function
+	 result) if the name is non-recursive.  */
+
+      st = gfc_enclosing_unit (NULL);
+
+      if (st != NULL && st->state == COMP_FUNCTION
+	  && st->sym == sym
+	  && !sym->attr.recursive)
+	{
+	  e = gfc_get_expr ();
+	  e->symtree = symtree;
+	  e->expr_type = EXPR_VARIABLE;
+
+	  m = gfc_match_varspec (e, 0, false, true);
+	  break;
+	}
+
+    /* Match a function reference.  */
+    function0:
+      m = gfc_match_actual_arglist (0, &actual_arglist);
+      if (m == MATCH_NO)
+	{
+	  if (sym->attr.proc == PROC_ST_FUNCTION)
+	    gfc_error ("Statement function '%s' requires argument list at %C",
+		       sym->name);
+	  else
+	    gfc_error ("Function '%s' requires an argument list at %C",
+		       sym->name);
+
+	  m = MATCH_ERROR;
+	  break;
+	}
+
+      if (m != MATCH_YES)
+	{
+	  m = MATCH_ERROR;
+	  break;
+	}
+
+      gfc_get_ha_sym_tree (name, &symtree);	/* Can't fail */
+      sym = symtree->n.sym;
+
+      replace_hidden_procptr_result (&sym, &symtree);
+
+      e = gfc_get_expr ();
+      e->symtree = symtree;
+      e->expr_type = EXPR_FUNCTION;
+      e->value.function.actual = actual_arglist;
+      e->where = gfc_current_locus;
+
+      if (sym->ts.type == BT_CLASS && sym->attr.class_ok
+	  && CLASS_DATA (sym)->as)
+	e->rank = CLASS_DATA (sym)->as->rank;
+      else if (sym->as != NULL)
+	e->rank = sym->as->rank;
+
+      if (!sym->attr.function
+	  && !gfc_add_function (&sym->attr, sym->name, NULL))
+	{
+	  m = MATCH_ERROR;
+	  break;
+	}
+
+      /* Check here for the existence of at least one argument for the
+         iso_c_binding functions C_LOC, C_FUNLOC, and C_ASSOCIATED.  The
+         argument(s) given will be checked in gfc_iso_c_func_interface,
+         during resolution of the function call.  */
+      if (sym->attr.is_iso_c == 1
+	  && (sym->from_intmod == INTMOD_ISO_C_BINDING
+	      && (sym->intmod_sym_id == ISOCBINDING_LOC
+		  || sym->intmod_sym_id == ISOCBINDING_FUNLOC
+		  || sym->intmod_sym_id == ISOCBINDING_ASSOCIATED)))
+        {
+          /* make sure we were given a param */
+          if (actual_arglist == NULL)
+            {
+              gfc_error ("Missing argument to '%s' at %C", sym->name);
+              m = MATCH_ERROR;
+              break;
+            }
+        }
+
+      if (sym->result == NULL)
+	sym->result = sym;
+
+      m = MATCH_YES;
+      break;
+
+    case FL_UNKNOWN:
+
+      /* Special case for derived type variables that get their types
+	 via an IMPLICIT statement.  This can't wait for the
+	 resolution phase.  */
+
+      if (gfc_peek_ascii_char () == '%'
+	  && sym->ts.type == BT_UNKNOWN
+	  && gfc_get_default_type (sym->name, sym->ns)->type == BT_DERIVED)
+	gfc_set_default_type (sym, 0, sym->ns);
+
+      /* If the symbol has a (co)dimension attribute, the expression is a
+	 variable.  */
+
+      if (sym->attr.dimension || sym->attr.codimension)
+	{
+	  if (!gfc_add_flavor (&sym->attr, FL_VARIABLE, sym->name, NULL))
+	    {
+	      m = MATCH_ERROR;
+	      break;
+	    }
+
+	  e = gfc_get_expr ();
+	  e->symtree = symtree;
+	  e->expr_type = EXPR_VARIABLE;
+	  m = gfc_match_varspec (e, 0, false, true);
+	  break;
+	}
+
+      if (sym->ts.type == BT_CLASS && sym->attr.class_ok
+	  && (CLASS_DATA (sym)->attr.dimension
+	      || CLASS_DATA (sym)->attr.codimension))
+	{
+	  if (!gfc_add_flavor (&sym->attr, FL_VARIABLE, sym->name, NULL))
+	    {
+	      m = MATCH_ERROR;
+	      break;
+	    }
+
+	  e = gfc_get_expr ();
+	  e->symtree = symtree;
+	  e->expr_type = EXPR_VARIABLE;
+	  m = gfc_match_varspec (e, 0, false, true);
+	  break;
+	}
+
+      /* Name is not an array, so we peek to see if a '(' implies a
+	 function call or a substring reference.  Otherwise the
+	 variable is just a scalar.  */
+
+      gfc_gobble_whitespace ();
+      if (gfc_peek_ascii_char () != '(')
+	{
+	  /* Assume a scalar variable */
+	  e = gfc_get_expr ();
+	  e->symtree = symtree;
+	  e->expr_type = EXPR_VARIABLE;
+
+	  if (!gfc_add_flavor (&sym->attr, FL_VARIABLE, sym->name, NULL))
+	    {
+	      m = MATCH_ERROR;
+	      break;
+	    }
+
+	  /*FIXME:??? gfc_match_varspec does set this for us: */
+	  e->ts = sym->ts;
+	  m = gfc_match_varspec (e, 0, false, true);
+	  break;
+	}
+
+      /* See if this is a function reference with a keyword argument
+	 as first argument. We do this because otherwise a spurious
+	 symbol would end up in the symbol table.  */
+
+      old_loc = gfc_current_locus;
+      m2 = gfc_match (" ( %n =", argname);
+      gfc_current_locus = old_loc;
+
+      e = gfc_get_expr ();
+      e->symtree = symtree;
+
+      if (m2 != MATCH_YES)
+	{
+	  /* Try to figure out whether we're dealing with a character type.
+	     We're peeking ahead here, because we don't want to call 
+	     match_substring if we're dealing with an implicitly typed
+	     non-character variable.  */
+	  implicit_char = false;
+	  if (sym->ts.type == BT_UNKNOWN)
+	    {
+	      ts = gfc_get_default_type (sym->name, NULL);
+	      if (ts->type == BT_CHARACTER)
+		implicit_char = true;
+	    }
+
+	  /* See if this could possibly be a substring reference of a name
+	     that we're not sure is a variable yet.  */
+
+	  if ((implicit_char || sym->ts.type == BT_CHARACTER)
+	      && match_substring (sym->ts.u.cl, 0, &e->ref) == MATCH_YES)
+	    {
+
+	      e->expr_type = EXPR_VARIABLE;
+
+	      if (sym->attr.flavor != FL_VARIABLE
+		  && !gfc_add_flavor (&sym->attr, FL_VARIABLE, 
+				      sym->name, NULL))
+		{
+		  m = MATCH_ERROR;
+		  break;
+		}
+
+	      if (sym->ts.type == BT_UNKNOWN
+		  && !gfc_set_default_type (sym, 1, NULL))
+		{
+		  m = MATCH_ERROR;
+		  break;
+		}
+
+	      e->ts = sym->ts;
+	      if (e->ref)
+		e->ts.u.cl = NULL;
+	      m = MATCH_YES;
+	      break;
+	    }
+	}
+
+      /* Give up, assume we have a function.  */
+
+      gfc_get_sym_tree (name, NULL, &symtree, false);	/* Can't fail */
+      sym = symtree->n.sym;
+      e->expr_type = EXPR_FUNCTION;
+
+      if (!sym->attr.function
+	  && !gfc_add_function (&sym->attr, sym->name, NULL))
+	{
+	  m = MATCH_ERROR;
+	  break;
+	}
+
+      sym->result = sym;
+
+      m = gfc_match_actual_arglist (0, &e->value.function.actual);
+      if (m == MATCH_NO)
+	gfc_error ("Missing argument list in function '%s' at %C", sym->name);
+
+      if (m != MATCH_YES)
+	{
+	  m = MATCH_ERROR;
+	  break;
+	}
+
+      /* If our new function returns a character, array or structure
+	 type, it might have subsequent references.  */
+
+      m = gfc_match_varspec (e, 0, false, true);
+      if (m == MATCH_NO)
+	m = MATCH_YES;
+
+      break;
+
+    generic_function:
+      gfc_get_sym_tree (name, NULL, &symtree, false);	/* Can't fail */
+
+      e = gfc_get_expr ();
+      e->symtree = symtree;
+      e->expr_type = EXPR_FUNCTION;
+
+      if (sym->attr.flavor == FL_DERIVED)
+	{
+	  e->value.function.esym = sym;
+	  e->symtree->n.sym->attr.generic = 1;
+	}
+
+      m = gfc_match_actual_arglist (0, &e->value.function.actual);
+      break;
+
+    default:
+      gfc_error ("Symbol at %C is not appropriate for an expression");
+      return MATCH_ERROR;
+    }
+
+  if (m == MATCH_YES)
+    {
+      e->where = where;
+      *result = e;
+    }
+  else
+    gfc_free_expr (e);
+
+  return m;
+}
+
+
+/* Match a variable, i.e. something that can be assigned to.  This
+   starts as a symbol, can be a structure component or an array
+   reference.  It can be a function if the function doesn't have a
+   separate RESULT variable.  If the symbol has not been previously
+   seen, we assume it is a variable.
+
+   This function is called by two interface functions:
+   gfc_match_variable, which has host_flag = 1, and
+   gfc_match_equiv_variable, with host_flag = 0, to restrict the
+   match of the symbol to the local scope.  */
+
+static match
+match_variable (gfc_expr **result, int equiv_flag, int host_flag)
+{
+  gfc_symbol *sym;
+  gfc_symtree *st;
+  gfc_expr *expr;
+  locus where;
+  match m;
+
+  /* Since nothing has any business being an lvalue in a module
+     specification block, an interface block or a contains section,
+     we force the changed_symbols mechanism to work by setting
+     host_flag to 0. This prevents valid symbols that have the name
+     of keywords, such as 'end', being turned into variables by
+     failed matching to assignments for, e.g., END INTERFACE.  */
+  if (gfc_current_state () == COMP_MODULE
+      || gfc_current_state () == COMP_INTERFACE
+      || gfc_current_state () == COMP_CONTAINS)
+    host_flag = 0;
+
+  where = gfc_current_locus;
+  m = gfc_match_sym_tree (&st, host_flag);
+  if (m != MATCH_YES)
+    return m;
+
+  sym = st->n.sym;
+
+  /* If this is an implicit do loop index and implicitly typed,
+     it should not be host associated.  */
+  m = check_for_implicit_index (&st, &sym);
+  if (m != MATCH_YES)
+    return m;
+
+  sym->attr.implied_index = 0;
+
+  gfc_set_sym_referenced (sym);
+  switch (sym->attr.flavor)
+    {
+    case FL_VARIABLE:
+      /* Everything is alright.  */
+      break;
+
+    case FL_UNKNOWN:
+      {
+	sym_flavor flavor = FL_UNKNOWN;
+
+	gfc_gobble_whitespace ();
+
+	if (sym->attr.external || sym->attr.procedure
+	    || sym->attr.function || sym->attr.subroutine)
+	  flavor = FL_PROCEDURE;
+
+	/* If it is not a procedure, is not typed and is host associated,
+	   we cannot give it a flavor yet.  */
+	else if (sym->ns == gfc_current_ns->parent
+		   && sym->ts.type == BT_UNKNOWN)
+	  break;
+
+	/* These are definitive indicators that this is a variable.  */
+	else if (gfc_peek_ascii_char () != '(' || sym->ts.type != BT_UNKNOWN
+		 || sym->attr.pointer || sym->as != NULL)
+	  flavor = FL_VARIABLE;
+
+	if (flavor != FL_UNKNOWN
+	    && !gfc_add_flavor (&sym->attr, flavor, sym->name, NULL))
+	  return MATCH_ERROR;
+      }
+      break;
+
+    case FL_PARAMETER:
+      if (equiv_flag)
+	{
+	  gfc_error ("Named constant at %C in an EQUIVALENCE");
+	  return MATCH_ERROR;
+	}
+      /* Otherwise this is checked for and an error given in the
+	 variable definition context checks.  */
+      break;
+
+    case FL_PROCEDURE:
+      /* Check for a nonrecursive function result variable.  */
+      if (sym->attr.function
+	  && !sym->attr.external
+	  && sym->result == sym
+	  && (gfc_is_function_return_value (sym, gfc_current_ns)
+	      || (sym->attr.entry
+		  && sym->ns == gfc_current_ns)
+	      || (sym->attr.entry
+		  && sym->ns == gfc_current_ns->parent)))
+	{
+	  /* If a function result is a derived type, then the derived
+	     type may still have to be resolved.  */
+
+	  if (sym->ts.type == BT_DERIVED
+	      && gfc_use_derived (sym->ts.u.derived) == NULL)
+	    return MATCH_ERROR;
+	  break;
+	}
+
+      if (sym->attr.proc_pointer
+	  || replace_hidden_procptr_result (&sym, &st))
+	break;
+
+      /* Fall through to error */
+
+    default:
+      gfc_error ("'%s' at %C is not a variable", sym->name);
+      return MATCH_ERROR;
+    }
+
+  /* Special case for derived type variables that get their types
+     via an IMPLICIT statement.  This can't wait for the
+     resolution phase.  */
+
+    {
+      gfc_namespace * implicit_ns;
+
+      if (gfc_current_ns->proc_name == sym)
+	implicit_ns = gfc_current_ns;
+      else
+	implicit_ns = sym->ns;
+	
+      if (gfc_peek_ascii_char () == '%'
+	  && sym->ts.type == BT_UNKNOWN
+	  && gfc_get_default_type (sym->name, implicit_ns)->type == BT_DERIVED)
+	gfc_set_default_type (sym, 0, implicit_ns);
+    }
+
+  expr = gfc_get_expr ();
+
+  expr->expr_type = EXPR_VARIABLE;
+  expr->symtree = st;
+  expr->ts = sym->ts;
+  expr->where = where;
+
+  /* Now see if we have to do more.  */
+  m = gfc_match_varspec (expr, equiv_flag, false, false);
+  if (m != MATCH_YES)
+    {
+      gfc_free_expr (expr);
+      return m;
+    }
+
+  *result = expr;
+  return MATCH_YES;
+}
+
+
+match
+gfc_match_variable (gfc_expr **result, int equiv_flag)
+{
+  return match_variable (result, equiv_flag, 1);
+}
+
+
+match
+gfc_match_equiv_variable (gfc_expr **result)
+{
+  return match_variable (result, 1, 0);
+}
+