Auto merge of #96683 - nnethercote:speed-up-Token-ident-lifetime, r=petrochenkov

Speed up `Token::{ident,lifetime}`

Some speed and cleanliness improvements.

r? `@petrochenkov`

2 files changed, 21 insertions, 11 deletions

diff --git a/compiler/rustc_ast/src/token.rs b/compiler/rustc_ast/src/token.rs
index 1589a882f08..1c366bc8e9a 100644
--- a/compiler/rustc_ast/src/token.rs
+++ b/compiler/rustc_ast/src/token.rs
@@ -475,19 +475,29 @@ impl Token {
     }
 
     /// Returns an identifier if this token is an identifier.
+    #[inline]
     pub fn ident(&self) -> Option<(Ident, /* is_raw */ bool)> {
-        let token = self.uninterpolate();
-        match token.kind {
-            Ident(name, is_raw) => Some((Ident::new(name, token.span), is_raw)),
+        // We avoid using `Token::uninterpolate` here because it's slow.
+        match &self.kind {
+            &Ident(name, is_raw) => Some((Ident::new(name, self.span), is_raw)),
+            Interpolated(nt) => match **nt {
+                NtIdent(ident, is_raw) => Some((ident, is_raw)),
+                _ => None,
+            },
             _ => None,
         }
     }
 
     /// Returns a lifetime identifier if this token is a lifetime.
+    #[inline]
     pub fn lifetime(&self) -> Option<Ident> {
-        let token = self.uninterpolate();
-        match token.kind {
-            Lifetime(name) => Some(Ident::new(name, token.span)),
+        // We avoid using `Token::uninterpolate` here because it's slow.
+        match &self.kind {
+            &Lifetime(name) => Some(Ident::new(name, self.span)),
+            Interpolated(nt) => match **nt {
+                NtLifetime(ident) => Some(ident),
+                _ => None,
+            },
             _ => None,
         }
     }
@@ -521,7 +531,7 @@ impl Token {
     /// (which happens while parsing the result of macro expansion)?
     pub fn is_whole_expr(&self) -> bool {
         if let Interpolated(ref nt) = self.kind
-            && let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtIdent(..) | NtBlock(_) = **nt
+            && let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtBlock(_) = **nt
         {
             return true;
         }
diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs
index 94b6c3153ca..fdd8dc93fc1 100644
--- a/compiler/rustc_expand/src/mbe/transcribe.rs
+++ b/compiler/rustc_expand/src/mbe/transcribe.rs
@@ -217,10 +217,10 @@ pub(super) fn transcribe<'a>(
             }
 
             // Replace the meta-var with the matched token tree from the invocation.
-            mbe::TokenTree::MetaVar(mut sp, mut orignal_ident) => {
+            mbe::TokenTree::MetaVar(mut sp, mut original_ident) => {
                 // Find the matched nonterminal from the macro invocation, and use it to replace
                 // the meta-var.
-                let ident = MacroRulesNormalizedIdent::new(orignal_ident);
+                let ident = MacroRulesNormalizedIdent::new(original_ident);
                 if let Some(cur_matched) = lookup_cur_matched(ident, interp, &repeats) {
                     match cur_matched {
                         MatchedTokenTree(ref tt) => {
@@ -249,9 +249,9 @@ pub(super) fn transcribe<'a>(
                     // If we aren't able to match the meta-var, we push it back into the result but
                     // with modified syntax context. (I believe this supports nested macros).
                     marker.visit_span(&mut sp);
-                    marker.visit_ident(&mut orignal_ident);
+                    marker.visit_ident(&mut original_ident);
                     result.push(TokenTree::token(token::Dollar, sp).into());
-                    result.push(TokenTree::Token(Token::from_ast_ident(orignal_ident)).into());
+                    result.push(TokenTree::Token(Token::from_ast_ident(original_ident)).into());
                 }
             }