Fortran: Fix CLASS conversion check [PR102745]

PR fortran/102745
gcc/fortran/ChangeLog
	* intrinsic.c (gfc_convert_type_warn): Fix checks by checking CLASS
	and do typcheck in correct order for type extension.
	* misc.c (gfc_typename): Print proper not internal CLASS type name.

gcc/testsuite/ChangeLog
	* gfortran.dg/class_72.f90: New.

gcc/fortran/intrinsic.c

@@ -5237,12 +5237,13 @@ gfc_convert_type_warn (gfc_expr *expr, gfc_typespec *ts, int eflag, int wflag,
   /* In building an array constructor, gfortran can end up here when no
      conversion is required for an intrinsic type.  We need to let derived
      types drop through.  */
-  if (from_ts.type != BT_DERIVED
+  if (from_ts.type != BT_DERIVED && from_ts.type != BT_CLASS
       && (from_ts.type == ts->type && from_ts.kind == ts->kind))
     return true;
 
-  if (expr->ts.type == BT_DERIVED && ts->type == BT_DERIVED
-      && gfc_compare_types (&expr->ts, ts))
+  if ((expr->ts.type == BT_DERIVED || expr->ts.type == BT_CLASS)
+      && (ts->type == BT_DERIVED || ts->type == BT_CLASS)
+      && gfc_compare_types (ts, &expr->ts))
     return true;
 
   /* If array is true then conversion is in an array constructor where

gcc/fortran/misc.c

@@ -130,7 +130,6 @@ gfc_typename (gfc_typespec *ts, bool for_hash)
   static char buffer2[GFC_MAX_SYMBOL_LEN + 8];
   static int flag = 0;
   char *buffer;
-  gfc_typespec *ts1;
   gfc_charlen_t length = 0;
 
   buffer = flag ? buffer1 : buffer2;
@@ -180,16 +179,17 @@ gfc_typename (gfc_typespec *ts, bool for_hash)
       sprintf (buffer, "TYPE(%s)", ts->u.derived->name);
       break;
     case BT_CLASS:
-      if (ts->u.derived == NULL)
+      if (!ts->u.derived || !ts->u.derived->components
+	  || !ts->u.derived->components->ts.u.derived)
 	{
 	  sprintf (buffer, "invalid class");
 	  break;
 	}
-      ts1 = ts->u.derived->components ? &ts->u.derived->components->ts : NULL;
-      if (ts1 && ts1->u.derived && ts1->u.derived->attr.unlimited_polymorphic)
+      if (ts->u.derived->components->ts.u.derived->attr.unlimited_polymorphic)
 	sprintf (buffer, "CLASS(*)");
       else
-	sprintf (buffer, "CLASS(%s)", ts->u.derived->name);
+	sprintf (buffer, "CLASS(%s)",
+		 ts->u.derived->components->ts.u.derived->name);
       break;
     case BT_ASSUMED:
       sprintf (buffer, "TYPE(*)");

gcc/testsuite/gfortran.dg/class_72.f90

@@ -0,0 +1,83 @@
+! PR fortran/102745
+
+implicit none
+
+type t
+end type t
+
+type, extends(t) :: t2
+end type t2
+
+type t3
+end type t3
+
+type(t), allocatable :: var
+type(t2), allocatable :: v2ar
+type(t3), allocatable :: v3ar
+class(t), allocatable :: cvar
+class(t2), allocatable :: c2var
+class(t3), allocatable :: c3var
+
+call f(var)
+call f(v2ar)   ! { dg-error "passed TYPE.t2. to TYPE.t." }
+call f(v2ar%t)
+call f(cvar)
+call f(c2var)  ! { dg-error "passed CLASS.t2. to TYPE.t." }
+call f(c2var%t)
+
+call f2(var)   ! { dg-error "passed TYPE.t. to TYPE.t2." }
+call f2(v2ar)
+call f2(cvar)  ! { dg-error "passed CLASS.t. to TYPE.t2." }
+call f2(c2var)
+
+
+var = var
+var = v2ar  ! { dg-error "TYPE.t2. to TYPE.t." }
+var = cvar
+var = c2var ! { dg-error "TYPE.t2. to TYPE.t." }
+
+v2ar = var  ! { dg-error "Cannot convert TYPE.t. to TYPE.t2." }
+v2ar = v2ar
+v2ar = cvar ! { dg-error "Cannot convert TYPE.t. to TYPE.t2." }
+v2ar = c2var
+
+cvar = var
+cvar = v2ar
+cvar = cvar
+cvar = c2var
+
+c2var = var   ! { dg-error "Cannot convert TYPE.t. to CLASS.t2." }
+c2var = v3ar  ! { dg-error "Cannot convert TYPE.t3. to CLASS.t2." }
+c2var = v2ar
+c2var = cvar  ! { dg-error "Cannot convert CLASS.t. to CLASS.t2." }
+c2var = c3var ! { dg-error "Cannot convert CLASS.t3. to CLASS.t2." }
+c2var = c2var
+
+allocate (var, source=var)
+allocate (var, source=v2ar)   ! { dg-error "incompatible with source-expr" }
+allocate (var, source=cvar)
+allocate (var, source=c2var)  ! { dg-error "incompatible with source-expr" }
+
+allocate (v2ar, source=var)   ! { dg-error "incompatible with source-expr" }
+allocate (v2ar, source=v2ar)
+allocate (v2ar, source=cvar)  ! { dg-error "incompatible with source-expr" }
+allocate (v2ar, source=c2var)
+
+allocate (cvar, source=var)
+allocate (cvar, source=v2ar)
+allocate (cvar, source=cvar)
+allocate (cvar, source=c2var)
+
+allocate (c2var, source=var)  ! { dg-error "incompatible with source-expr" }
+allocate (c2var, source=v2ar)
+allocate (c2var, source=cvar) ! { dg-error "incompatible with source-expr" }
+allocate (c2var, source=c2var)
+
+contains
+ subroutine f(x)
+   type(t) :: x
+ end
+ subroutine f2(x)
+   type(t2) :: x
+ end
+end