[Bug c++/125711] [14/15/16/17 Regression] internal compiler error: tree check: expected class 'expression', have 'declaration' (var_decl) in tree_operand_check, at tree.h:4349

[mpolacek at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125711

--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I think it's this hunk:

+     /* Handlers can refer to the function result; if that has been
+        moved, we need to track it.  */
+     if (gimplify_ctxp->in_handler_expr && gimplify_ctxp->return_temp)
+       *expr_p = gimplify_ctxp->return_temp;

which rewrites *expr_p from a RESULT_DECL into a VAR_DECL.  Then in
gimplify_return_expr we don't take the 

  if (!ret_expr
      || TREE_CODE (ret_expr) == RESULT_DECL)

path.