Use `token::Lit` in `ast::ExprKind::Lit`.

Instead of `ast::Lit`.

Literal lowering now happens at two different times. Expression literals
are lowered when HIR is crated. Attribute literals are lowered during
parsing.

This commit changes the language very slightly. Some programs that used
to not compile now will compile. This is because some invalid literals
that are removed by `cfg` or attribute macros will no longer trigger
errors. See this comment for more details:
https://github.com/rust-lang/rust/pull/102944#issuecomment-1277476773

1 files changed, 1 insertions, 1 deletions

diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 18b661034e0..7820bbc1789 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -359,7 +359,7 @@ impl<'a> Parser<'a> {
     /// report error for `let 1x = 123`
     pub fn report_invalid_identifier_error(&mut self) -> PResult<'a, ()> {
         if let token::Literal(lit) = self.token.uninterpolate().kind &&
-            let Err(_) = rustc_ast::Lit::from_token(&self.token) &&
+            rustc_ast::Lit::from_token(&self.token).is_none() &&
             (lit.kind == token::LitKind::Integer || lit.kind == token::LitKind::Float) &&
             self.look_ahead(1, |t| matches!(t.kind, token::Eq) || matches!(t.kind, token::Colon ) ) {
                 return Err(self.sess.create_err(InvalidIdentiferStartsWithNumber { span: self.token.span }));