Remove `NtPat`.

The one notable test change is `tests/ui/macros/trace_faulty_macros.rs`.
This commit removes the complicated `Interpolated` handling in
`expected_expression_found` that results in a longer error message. But
I think the new, shorter message is actually an improvement.

The original complaint was in #71039, when the error message started
with "error: expected expression, found `1 + 1`". That was confusing
because `1 + 1` is an expression. Other than that, the reporter said
"the whole error message is not too bad if you ignore the first line".

Subsequently, extra complexity and wording was added to the error
message. But I don't think the extra wording actually helps all that
much. In particular, it still says of the `1+1` that "this is expected
to be expression". This repeats the problem from the original complaint!

This commit removes the extra complexity, reverting to a simpler error
message. This is primarily because the traversal is a pain without
`Interpolated` tokens. Nonetheless, I think the error message is
*improved*. It now starts with "expected expression, found `pat`
metavariable", which is much clearer and the real problem. It also
doesn't say anything specific about `1+1`, which is good, because the
`1+1` isn't really relevant to the error -- it's the `$e:pat` that's
important.

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/ui/macros/trace_faulty_macros.rs b/tests/ui/macros/trace_faulty_macros.rs
index 87036bb9c6f..e0cbbd8f5c9 100644
--- a/tests/ui/macros/trace_faulty_macros.rs
+++ b/tests/ui/macros/trace_faulty_macros.rs
@@ -46,7 +46,7 @@ macro_rules! test {
     (let $p:pat = $e:expr) => {test!(($p,$e))};
     // this should be expr
     //           vvv
-    (($p:pat, $e:pat)) => {let $p = $e;}; //~ ERROR expected expression, found pattern `1+1`
+    (($p:pat, $e:pat)) => {let $p = $e;}; //~ ERROR expected expression, found `pat` metavariable
 }
 
 fn foo() {