Auto merge of rust-lang#127728 - matthiaskrgr:rollup-ercdbjd, r=matth…

…iaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#127273 (Fix `DebugParser`.)
 - rust-lang#127587 (Report usage of lib features in ast validation)
 - rust-lang#127592 (doc: Suggest `str::repeat` over `iter::repeat().take().collect()`)
 - rust-lang#127630 (Remove lang feature for type ascription (since it's a lib feature now))
 - rust-lang#127711 (Add regression test for a gce + effects ICE)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -607,8 +607,7 @@ fn maybe_stage_features(sess: &Session, features: &Features, krate: &ast::Crate)
     // does not check the same for lib features unless there's at least one
     // declared lang feature
     if !sess.opts.unstable_features.is_nightly_build() {
-        let lang_features = &features.declared_lang_features;
-        if lang_features.len() == 0 {
+        if features.declared_features.is_empty() {
             return;
         }
         for attr in krate.attrs.iter().filter(|attr| attr.has_name(sym::feature)) {
@@ -624,7 +623,8 @@ fn maybe_stage_features(sess: &Session, features: &Features, krate: &ast::Crate)
                 attr.meta_item_list().into_iter().flatten().flat_map(|nested| nested.ident())
             {
                 let name = ident.name;
-                let stable_since = lang_features
+                let stable_since = features
+                    .declared_lang_features
                     .iter()
                     .flat_map(|&(feature, _, since)| if feature == name { since } else { None })
                     .next();

compiler/rustc_codegen_gcc/example/mini_core.rs

@@ -1,5 +1,5 @@
 #![feature(
-    no_core, lang_items, intrinsics, unboxed_closures, type_ascription, extern_types,
+    no_core, lang_items, intrinsics, unboxed_closures, extern_types,
     decl_macro, rustc_attrs, transparent_unions, auto_traits, freeze_impls,
     thread_local
 )]

compiler/rustc_feature/src/unstable.rs

@@ -621,8 +621,6 @@ declare_features! (
     (unstable, try_blocks, "1.29.0", Some(31436)),
     /// Allows `impl Trait` to be used inside type aliases (RFC 2515).
     (unstable, type_alias_impl_trait, "1.38.0", Some(63063)),
-    /// Allows the use of type ascription in expressions.
-    (unstable, type_ascription, "1.6.0", Some(23416)),
     /// Allows creation of instances of a struct by moving fields that have
     /// not changed from prior instances of the same struct (RFC #2528)
     (unstable, type_changing_struct_update, "1.58.0", Some(86555)),

compiler/rustc_parse/src/parser/mod.rs

@@ -1537,14 +1537,16 @@ impl<'a> Parser<'a> {
 
                 // we don't need N spans, but we want at least one, so print all of prev_token
                 dbg_fmt.field("prev_token", &parser.prev_token);
-                // make it easier to peek farther ahead by taking TokenKinds only until EOF
-                let tokens = (0..*lookahead)
-                    .map(|i| parser.look_ahead(i, |tok| tok.kind.clone()))
-                    .scan(parser.prev_token == TokenKind::Eof, |eof, tok| {
-                        let current = eof.then_some(tok.clone()); // include a trailing EOF token
-                        *eof |= &tok == &TokenKind::Eof;
-                        current
-                    });
+                let mut tokens = vec![];
+                for i in 0..*lookahead {
+                    let tok = parser.look_ahead(i, |tok| tok.kind.clone());
+                    let is_eof = tok == TokenKind::Eof;
+                    tokens.push(tok);
+                    if is_eof {
+                        // Don't look ahead past EOF.
+                        break;
+                    }
+                }
                 dbg_fmt.field_with("tokens", |field| field.debug_list().entries(tokens).finish());
                 dbg_fmt.field("approx_token_stream_pos", &parser.num_bump_calls);