[gcc/devel/rust/master] Remove param_use_canonical_types checks ported from c++ front-end

[Thomas Schwinge <tschwinge@gcc.gnu.org>]

https://gcc.gnu.org/g:b1cf3a384d41fa34c1eb819696e66fa65625d8db

commit b1cf3a384d41fa34c1eb819696e66fa65625d8db
Author: Philip Herron <philip.herron@embecosm.com>
Date:   Wed Aug 31 14:08:43 2022 +0100

    Remove param_use_canonical_types checks ported from c++ front-end
    
    We are not fully setting TYPE_CANONICAL yet but we don't need to be as
    strict as the C++ front-end yet. param_use_canonical_types is a command
    line option we are not using either.

Diff:
---
 gcc/rust/backend/rust-tree.cc | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/gcc/rust/backend/rust-tree.cc b/gcc/rust/backend/rust-tree.cc
index 9dac0dce53d..f5878356841 100644
--- a/gcc/rust/backend/rust-tree.cc
+++ b/gcc/rust/backend/rust-tree.cc
@@ -2916,27 +2916,7 @@ comptypes (tree t1, tree t2, int strict)
 	   perform a deep check. */
 	return structural_comptypes (t1, t2, strict);
 
-      if (flag_checking && param_use_canonical_types)
-	{
-	  bool result = structural_comptypes (t1, t2, strict);
-
-	  if (result && TYPE_CANONICAL (t1) != TYPE_CANONICAL (t2))
-	    /* The two types are structurally equivalent, but their
-	       canonical types were different. This is a failure of the
-	       canonical type propagation code.*/
-	    internal_error (
-	      "canonical types differ for identical types %qT and %qT", t1, t2);
-	  else if (!result && TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2))
-	    /* Two types are structurally different, but the canonical
-	       types are the same. This means we were over-eager in
-	       assigning canonical types. */
-	    internal_error (
-	      "same canonical type node for different types %qT and %qT", t1,
-	      t2);
-
-	  return result;
-	}
-      if (!flag_checking && param_use_canonical_types)
+      if (!flag_checking)
 	return TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2);
       else
 	return structural_comptypes (t1, t2, strict);