Rollup merge of #149903 - JonathanBrouwer:cfg_old_cleanup, r=jdonszelmann

Remove unused code in `cfg_old`

r? ```@jdonszelmann```

Fixes one of the todos from https://github.com/rust-lang/rust/issues/149865

compiler/rustc_attr_parsing/messages.ftl

@@ -6,9 +6,6 @@ attr_parsing_bundle_needs_static =
 
 attr_parsing_cfg_attr_bad_delim = wrong `cfg_attr` delimiters
 
-attr_parsing_cfg_predicate_identifier =
-    `cfg` predicate key must be an identifier
-
 attr_parsing_deprecated_item_suggestion =
     suggestions on deprecated items are unstable
     .help = add `#![feature(deprecated_suggestion)]` to the crate root
@@ -41,9 +38,6 @@ attr_parsing_empty_link_name =
     link name must not be empty
     .label = empty link name
 
-attr_parsing_expected_one_cfg_pattern =
-    expected 1 cfg-pattern
-
 attr_parsing_expected_single_version_literal =
     expected single version literal
 
@@ -241,12 +235,6 @@ attr_parsing_unstable_cfg_target_compact =
 attr_parsing_unstable_feature_bound_incompatible_stability = item annotated with `#[unstable_feature_bound]` should not be stable
     .help = If this item is meant to be stable, do not use any functions annotated with `#[unstable_feature_bound]`. Otherwise, mark this item as unstable with `#[unstable]`
 
-attr_parsing_unsupported_literal_cfg_boolean =
-    literal in `cfg` predicate value must be a boolean
-attr_parsing_unsupported_literal_cfg_string =
-    literal in `cfg` predicate value must be a string
-attr_parsing_unsupported_literal_generic =
-    unsupported literal
 attr_parsing_unsupported_literal_suggestion =
     consider removing the prefix
 

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -4,7 +4,9 @@
 use rustc_ast::tokenstream::DelimSpan;
 use rustc_ast::{AttrItem, Attribute, CRATE_NODE_ID, LitKind, ast, token};
 use rustc_errors::{Applicability, PResult};
-use rustc_feature::{AttrSuggestionStyle, AttributeTemplate, Features, template};
+use rustc_feature::{
+    AttrSuggestionStyle, AttributeTemplate, Features, GatedCfg, find_gated_cfg, template,
+};
 use rustc_hir::attrs::CfgEntry;
 use rustc_hir::lints::AttributeLintKind;
 use rustc_hir::{AttrPath, RustcVersion};
@@ -23,7 +25,7 @@
     AttributeParseError, AttributeParseErrorReason, CfgAttrBadDelim, MetaBadDelimSugg,
     ParsedDescription,
 };
-use crate::{AttributeParser, fluent_generated, parse_version, session_diagnostics, try_gate_cfg};
+use crate::{AttributeParser, fluent_generated, parse_version, session_diagnostics};
 
 pub const CFG_TEMPLATE: AttributeTemplate = template!(
     List: &["predicate"],
@@ -410,3 +412,19 @@ fn parse_cfg_attr_internal<'a>(
 
     Ok((cfg_predicate, expanded_attrs))
 }
+
+fn try_gate_cfg(name: Symbol, span: Span, sess: &Session, features: Option<&Features>) {
+    let gate = find_gated_cfg(|sym| sym == name);
+    if let (Some(feats), Some(gated_cfg)) = (features, gate) {
+        gate_cfg(gated_cfg, span, sess, feats);
+    }
+}
+
+#[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
+fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &Session, features: &Features) {
+    let (cfg, feature, has_feature) = gated_cfg;
+    if !has_feature(features) && !cfg_span.allows_unstable(*feature) {
+        let explain = format!("`cfg({cfg})` is experimental and subject to change");
+        feature_err(sess, *feature, cfg_span, explain).emit();
+    }
+}

compiler/rustc_attr_parsing/src/attributes/cfg_old.rs

@@ -1,210 +0,0 @@
-use rustc_ast::{LitKind, MetaItem, MetaItemInner, MetaItemKind, MetaItemLit, NodeId};
-use rustc_ast_pretty::pprust;
-use rustc_feature::{Features, GatedCfg, find_gated_cfg};
-use rustc_hir::RustcVersion;
-use rustc_session::Session;
-use rustc_session::lint::{BuiltinLintDiag, Lint};
-use rustc_session::parse::feature_err;
-use rustc_span::{Span, Symbol, sym};
-
-use crate::session_diagnostics::{self, UnsupportedLiteralReason};
-use crate::{fluent_generated, parse_version};
-
-/// Emitter of a builtin lint from `cfg_matches`.
-///
-/// Used to support emitting a lint (currently on check-cfg), either:
-///  - as an early buffered lint (in `rustc`)
-///  - or has a "normal" lint from HIR (in `rustdoc`)
-pub trait CfgMatchesLintEmitter {
-    fn emit_span_lint(&self, sess: &Session, lint: &'static Lint, sp: Span, diag: BuiltinLintDiag);
-}
-
-impl CfgMatchesLintEmitter for NodeId {
-    fn emit_span_lint(&self, sess: &Session, lint: &'static Lint, sp: Span, diag: BuiltinLintDiag) {
-        sess.psess.buffer_lint(lint, sp, *self, diag);
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct Condition {
-    pub name: Symbol,
-    pub name_span: Span,
-    pub value: Option<Symbol>,
-    pub value_span: Option<Span>,
-    pub span: Span,
-}
-
-pub fn try_gate_cfg(name: Symbol, span: Span, sess: &Session, features: Option<&Features>) {
-    let gate = find_gated_cfg(|sym| sym == name);
-    if let (Some(feats), Some(gated_cfg)) = (features, gate) {
-        gate_cfg(gated_cfg, span, sess, feats);
-    }
-}
-
-#[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
-fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &Session, features: &Features) {
-    let (cfg, feature, has_feature) = gated_cfg;
-    if !has_feature(features) && !cfg_span.allows_unstable(*feature) {
-        let explain = format!("`cfg({cfg})` is experimental and subject to change");
-        feature_err(sess, *feature, cfg_span, explain).emit();
-    }
-}
-
-/// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to
-/// evaluate individual items.
-pub fn eval_condition(
-    cfg: &MetaItemInner,
-    sess: &Session,
-    features: Option<&Features>,
-    eval: &mut impl FnMut(Condition) -> bool,
-) -> bool {
-    let dcx = sess.dcx();
-
-    let cfg = match cfg {
-        MetaItemInner::MetaItem(meta_item) => meta_item,
-        MetaItemInner::Lit(MetaItemLit { kind: LitKind::Bool(b), .. }) => {
-            return *b;
-        }
-        _ => {
-            dcx.emit_err(session_diagnostics::UnsupportedLiteral {
-                span: cfg.span(),
-                reason: UnsupportedLiteralReason::CfgBoolean,
-                is_bytestr: false,
-                start_point_span: sess.source_map().start_point(cfg.span()),
-            });
-            return false;
-        }
-    };
-
-    match &cfg.kind {
-        MetaItemKind::List(mis) if cfg.has_name(sym::version) => {
-            try_gate_cfg(sym::version, cfg.span, sess, features);
-            let (min_version, span) = match &mis[..] {
-                [MetaItemInner::Lit(MetaItemLit { kind: LitKind::Str(sym, ..), span, .. })] => {
-                    (sym, span)
-                }
-                [
-                    MetaItemInner::Lit(MetaItemLit { span, .. })
-                    | MetaItemInner::MetaItem(MetaItem { span, .. }),
-                ] => {
-                    dcx.emit_err(session_diagnostics::ExpectedVersionLiteral { span: *span });
-                    return false;
-                }
-                [..] => {
-                    dcx.emit_err(session_diagnostics::ExpectedSingleVersionLiteral {
-                        span: cfg.span,
-                    });
-                    return false;
-                }
-            };
-            let Some(min_version) = parse_version(*min_version) else {
-                dcx.emit_warn(session_diagnostics::UnknownVersionLiteral { span: *span });
-                return false;
-            };
-
-            // See https://github.com/rust-lang/rust/issues/64796#issuecomment-640851454 for details
-            if sess.psess.assume_incomplete_release {
-                RustcVersion::current_overridable() > min_version
-            } else {
-                RustcVersion::current_overridable() >= min_version
-            }
-        }
-        MetaItemKind::List(mis) => {
-            for mi in mis.iter() {
-                if mi.meta_item_or_bool().is_none() {
-                    dcx.emit_err(session_diagnostics::UnsupportedLiteral {
-                        span: mi.span(),
-                        reason: UnsupportedLiteralReason::Generic,
-                        is_bytestr: false,
-                        start_point_span: sess.source_map().start_point(mi.span()),
-                    });
-                    return false;
-                }
-            }
-
-            // The unwraps below may look dangerous, but we've already asserted
-            // that they won't fail with the loop above.
-            match cfg.name() {
-                Some(sym::any) => mis
-                    .iter()
-                    // We don't use any() here, because we want to evaluate all cfg condition
-                    // as eval_condition can (and does) extra checks
-                    .fold(false, |res, mi| res | eval_condition(mi, sess, features, eval)),
-                Some(sym::all) => mis
-                    .iter()
-                    // We don't use all() here, because we want to evaluate all cfg condition
-                    // as eval_condition can (and does) extra checks
-                    .fold(true, |res, mi| res & eval_condition(mi, sess, features, eval)),
-                Some(sym::not) => {
-                    let [mi] = mis.as_slice() else {
-                        dcx.emit_err(session_diagnostics::ExpectedOneCfgPattern { span: cfg.span });
-                        return false;
-                    };
-
-                    !eval_condition(mi, sess, features, eval)
-                }
-                Some(sym::target) => {
-                    if let Some(features) = features
-                        && !features.cfg_target_compact()
-                    {
-                        feature_err(
-                            sess,
-                            sym::cfg_target_compact,
-                            cfg.span,
-                            fluent_generated::attr_parsing_unstable_cfg_target_compact,
-                        )
-                        .emit();
-                    }
-
-                    mis.iter().fold(true, |res, mi| {
-                        let Some(mut mi) = mi.meta_item().cloned() else {
-                            dcx.emit_err(session_diagnostics::CfgPredicateIdentifier {
-                                span: mi.span(),
-                            });
-                            return false;
-                        };
-
-                        if let [seg, ..] = &mut mi.path.segments[..] {
-                            seg.ident.name = Symbol::intern(&format!("target_{}", seg.ident.name));
-                        }
-
-                        res & eval_condition(&MetaItemInner::MetaItem(mi), sess, features, eval)
-                    })
-                }
-                _ => {
-                    dcx.emit_err(session_diagnostics::InvalidPredicate {
-                        span: cfg.span,
-                        predicate: pprust::path_to_string(&cfg.path),
-                    });
-                    false
-                }
-            }
-        }
-        MetaItemKind::Word | MetaItemKind::NameValue(..)
-            if cfg.path.segments.len() != 1
-                || cfg.path.segments[0].ident.is_path_segment_keyword() =>
-        {
-            dcx.emit_err(session_diagnostics::CfgPredicateIdentifier { span: cfg.path.span });
-            true
-        }
-        MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
-            dcx.emit_err(session_diagnostics::UnsupportedLiteral {
-                span: lit.span,
-                reason: UnsupportedLiteralReason::CfgString,
-                is_bytestr: lit.kind.is_bytestr(),
-                start_point_span: sess.source_map().start_point(lit.span),
-            });
-            true
-        }
-        MetaItemKind::Word | MetaItemKind::NameValue(..) => {
-            let ident = cfg.ident().expect("multi-segment cfg predicate");
-            eval(Condition {
-                name: ident.name,
-                name_span: ident.span,
-                value: cfg.value_str(),
-                value_span: cfg.name_value_literal_span(),
-                span: cfg.span,
-            })
-        }
-    }
-}

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -32,7 +32,6 @@
 pub(crate) mod allow_unstable;
 pub(crate) mod body;
 pub(crate) mod cfg;
-pub(crate) mod cfg_old;
 pub(crate) mod cfg_select;
 pub(crate) mod codegen_attrs;
 pub(crate) mod confusables;

compiler/rustc_attr_parsing/src/attributes/stability.rs

@@ -8,7 +8,7 @@
 
 use super::prelude::*;
 use super::util::parse_version;
-use crate::session_diagnostics::{self, UnsupportedLiteralReason};
+use crate::session_diagnostics::{self};
 
 macro_rules! reject_outside_std {
     ($cx: ident) => {
@@ -302,12 +302,7 @@ pub(crate) fn parse_stability<S: Stage>(
     for param in list.mixed() {
         let param_span = param.span();
         let Some(param) = param.meta_item() else {
-            cx.emit_err(session_diagnostics::UnsupportedLiteral {
-                span: param_span,
-                reason: UnsupportedLiteralReason::Generic,
-                is_bytestr: false,
-                start_point_span: cx.sess().source_map().start_point(param_span),
-            });
+            cx.unexpected_literal(param.span());
             return None;
         };
 
@@ -382,12 +377,7 @@ pub(crate) fn parse_unstability<S: Stage>(
 
     for param in list.mixed() {
         let Some(param) = param.meta_item() else {
-            cx.emit_err(session_diagnostics::UnsupportedLiteral {
-                span: param.span(),
-                reason: UnsupportedLiteralReason::Generic,
-                is_bytestr: false,
-                start_point_span: cx.sess().source_map().start_point(param.span()),
-            });
+            cx.unexpected_literal(param.span());
             return None;
         };
 

compiler/rustc_attr_parsing/src/lib.rs

@@ -107,7 +107,6 @@
 pub use attributes::cfg::{
     CFG_TEMPLATE, EvalConfigResult, eval_config_entry, parse_cfg, parse_cfg_attr, parse_cfg_entry,
 };
-pub use attributes::cfg_old::*;
 pub use attributes::cfg_select::*;
 pub use attributes::util::{is_builtin_attr, parse_version};
 pub use context::{Early, Late, OmitDoc, ShouldEmit};

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -12,19 +12,6 @@
 
 use crate::fluent_generated as fluent;
 
-pub(crate) enum UnsupportedLiteralReason {
-    Generic,
-    CfgString,
-    CfgBoolean,
-}
-
-#[derive(Diagnostic)]
-#[diag(attr_parsing_expected_one_cfg_pattern, code = E0536)]
-pub(crate) struct ExpectedOneCfgPattern {
-    #[primary_span]
-    pub span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(attr_parsing_invalid_predicate, code = E0537)]
 pub(crate) struct InvalidPredicate {
@@ -230,46 +217,6 @@ pub(crate) struct InvalidReprHintNoValue {
     pub name: Symbol,
 }
 
-/// Error code: E0565
-// FIXME(jdonszelmann): slowly phased out
-pub(crate) struct UnsupportedLiteral {
-    pub span: Span,
-    pub reason: UnsupportedLiteralReason,
-    pub is_bytestr: bool,
-    pub start_point_span: Span,
-}
-
-impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for UnsupportedLiteral {
-    fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, G> {
-        let mut diag = Diag::new(
-            dcx,
-            level,
-            match self.reason {
-                UnsupportedLiteralReason::Generic => {
-                    fluent::attr_parsing_unsupported_literal_generic
-                }
-                UnsupportedLiteralReason::CfgString => {
-                    fluent::attr_parsing_unsupported_literal_cfg_string
-                }
-                UnsupportedLiteralReason::CfgBoolean => {
-                    fluent::attr_parsing_unsupported_literal_cfg_boolean
-                }
-            },
-        );
-        diag.span(self.span);
-        diag.code(E0565);
-        if self.is_bytestr {
-            diag.span_suggestion(
-                self.start_point_span,
-                fluent::attr_parsing_unsupported_literal_suggestion,
-                "",
-                Applicability::MaybeIncorrect,
-            );
-        }
-        diag
-    }
-}
-
 #[derive(Diagnostic)]
 #[diag(attr_parsing_invalid_repr_align_need_arg, code = E0589)]
 pub(crate) struct InvalidReprAlignNeedArg {
@@ -375,13 +322,6 @@ pub(crate) struct RustcAllowedUnstablePairing {
     pub span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag(attr_parsing_cfg_predicate_identifier)]
-pub(crate) struct CfgPredicateIdentifier {
-    #[primary_span]
-    pub span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(attr_parsing_deprecated_item_suggestion)]
 pub(crate) struct DeprecatedItemSuggestion {

compiler/rustc_error_codes/src/error_codes/E0536.md

@@ -1,3 +1,5 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 The `not` cfg-predicate was malformed.
 
 Erroneous code example (using `cargo doc`):