refactor constify most of rb_method_entry_t

Now that we have eliminated most destructive operations over the
rb_method_entry_t / rb_callable_method_entry_t, let's make them
mostly immutabe and mark them const.

One exception is rb_export_method(), which destructively modifies
visibilities of method entries.  I have left that operation as is
because I suspect that destructiveness is the nature of that
function.

1 files changed, 1 insertions, 1 deletions

diff --git a/ext/coverage/coverage.c b/ext/coverage/coverage.c
index 8503c9d6c6..cb571caa4b 100644
--- a/ext/coverage/coverage.c
+++ b/ext/coverage/coverage.c
@@ -123,7 +123,7 @@ method_coverage_i(void *vstart, void *vend, size_t stride, void *data)
 
     for (v = (VALUE)vstart; v != (VALUE)vend; v += stride) {
 	if (RB_TYPE_P(v, T_IMEMO) && imemo_type(v) == imemo_ment) {
-	    const rb_method_entry_t *me = (rb_method_entry_t *) v;
+            const rb_method_entry_t *me = (const rb_method_entry_t *) v;
 	    VALUE path, first_lineno, first_column, last_lineno, last_column;
 	    VALUE data[5], ncoverage, methods;
 	    VALUE methods_id = ID2SYM(rb_intern("methods"));