Rollup merge of rust-lang#146978 - mu001999-contrib:fix/path-kw-as-cfg-pred, r=petrochenkov

Emit error when using path-segment keyword as cfg pred

Fixes rust-lang#146968

Emit error `CfgPredicateIdentifier` if the word is path-segment keyword.

Detailed change description - rust-lang#146978 (comment).

r? petrochenkov

Author: Zalathar

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -82,7 +82,8 @@ pub fn parse_cfg_entry<S: Stage>(
                 }
             },
             a @ (ArgParser::NoArgs | ArgParser::NameValue(_)) => {
-                let Some(name) = meta.path().word_sym() else {
+                let Some(name) = meta.path().word_sym().filter(|s| !s.is_path_segment_keyword())
+                else {
                     return Err(cx.expected_identifier(meta.path().span()));
                 };
                 parse_name_value(name, meta.path().span(), a.name_value(), meta.span(), cx)?
@@ -158,7 +159,7 @@ fn parse_cfg_entry_target<S: Stage>(
         };
 
         // Then, parse it as a name-value item
-        let Some(name) = sub_item.path().word_sym() else {
+        let Some(name) = sub_item.path().word_sym().filter(|s| !s.is_path_segment_keyword()) else {
             return Err(cx.expected_identifier(sub_item.path().span()));
         };
         let name = Symbol::intern(&format!("target_{name}"));

compiler/rustc_attr_parsing/src/attributes/cfg_old.rs

@@ -220,7 +220,10 @@ pub fn eval_condition(
                 }
             }
         }
-        MetaItemKind::Word | MetaItemKind::NameValue(..) if cfg.path.segments.len() != 1 => {
+        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
         }

compiler/rustc_errors/src/emitter.rs

@@ -532,30 +532,24 @@ impl Emitter for HumanEmitter {
     }
 }
 
-/// An emitter that does nothing when emitting a non-fatal diagnostic.
-/// Fatal diagnostics are forwarded to `fatal_emitter` to avoid silent
-/// failures of rustc, as witnessed e.g. in issue #89358.
-pub struct FatalOnlyEmitter {
-    pub fatal_emitter: Box<dyn Emitter + DynSend>,
-    pub fatal_note: Option<String>,
+/// An emitter that adds a note to each diagnostic.
+pub struct EmitterWithNote {
+    pub emitter: Box<dyn Emitter + DynSend>,
+    pub note: String,
 }
 
-impl Emitter for FatalOnlyEmitter {
+impl Emitter for EmitterWithNote {
     fn source_map(&self) -> Option<&SourceMap> {
         None
     }
 
     fn emit_diagnostic(&mut self, mut diag: DiagInner, registry: &Registry) {
-        if diag.level == Level::Fatal {
-            if let Some(fatal_note) = &self.fatal_note {
-                diag.sub(Level::Note, fatal_note.clone(), MultiSpan::new());
-            }
-            self.fatal_emitter.emit_diagnostic(diag, registry);
-        }
+        diag.sub(Level::Note, self.note.clone(), MultiSpan::new());
+        self.emitter.emit_diagnostic(diag, registry);
     }
 
     fn translator(&self) -> &Translator {
-        self.fatal_emitter.translator()
+        self.emitter.translator()
     }
 }
 

compiler/rustc_interface/src/interface.rs

@@ -15,6 +15,7 @@ use rustc_middle::ty::CurrentGcx;
 use rustc_middle::util::Providers;
 use rustc_parse::lexer::StripTokens;
 use rustc_parse::new_parser_from_source_str;
+use rustc_parse::parser::Recovery;
 use rustc_parse::parser::attr::AllowLeadingUnsafe;
 use rustc_query_impl::QueryCtxt;
 use rustc_query_system::query::print_query_stack;
@@ -52,46 +53,56 @@ pub struct Compiler {
 pub(crate) fn parse_cfg(dcx: DiagCtxtHandle<'_>, cfgs: Vec<String>) -> Cfg {
     cfgs.into_iter()
         .map(|s| {
-            let psess = ParseSess::with_fatal_emitter(
+            let psess = ParseSess::emitter_with_note(
                 vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
-                format!("this error occurred on the command line: `--cfg={s}`"),
+                format!("this occurred on the command line: `--cfg={s}`"),
             );
             let filename = FileName::cfg_spec_source_code(&s);
 
             macro_rules! error {
                 ($reason: expr) => {
                     #[allow(rustc::untranslatable_diagnostic)]
                     #[allow(rustc::diagnostic_outside_of_impl)]
-                    dcx.fatal(format!(
-                        concat!("invalid `--cfg` argument: `{}` (", $reason, ")"),
-                        s
-                    ));
+                    dcx.fatal(format!("invalid `--cfg` argument: `{s}` ({})", $reason));
                 };
             }
 
             match new_parser_from_source_str(&psess, filename, s.to_string(), StripTokens::Nothing)
             {
-                Ok(mut parser) => match parser.parse_meta_item(AllowLeadingUnsafe::No) {
-                    Ok(meta_item) if parser.token == token::Eof => {
-                        if meta_item.path.segments.len() != 1 {
-                            error!("argument key must be an identifier");
-                        }
-                        match &meta_item.kind {
-                            MetaItemKind::List(..) => {}
-                            MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
-                                error!("argument value must be a string");
+                Ok(mut parser) => {
+                    parser = parser.recovery(Recovery::Forbidden);
+                    match parser.parse_meta_item(AllowLeadingUnsafe::No) {
+                        Ok(meta_item)
+                            if parser.token == token::Eof
+                                && parser.dcx().has_errors().is_none() =>
+                        {
+                            if meta_item.path.segments.len() != 1 {
+                                error!("argument key must be an identifier");
                             }
-                            MetaItemKind::NameValue(..) | MetaItemKind::Word => {
-                                let ident = meta_item.ident().expect("multi-segment cfg key");
-                                return (ident.name, meta_item.value_str());
+                            match &meta_item.kind {
+                                MetaItemKind::List(..) => {}
+                                MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
+                                    error!("argument value must be a string");
+                                }
+                                MetaItemKind::NameValue(..) | MetaItemKind::Word => {
+                                    let ident = meta_item.ident().expect("multi-segment cfg key");
+
+                                    if ident.is_path_segment_keyword() {
+                                        error!(
+                                            "malformed `cfg` input, expected a valid identifier"
+                                        );
+                                    }
+
+                                    return (ident.name, meta_item.value_str());
+                                }
                             }
                         }
+                        Ok(..) => {}
+                        Err(err) => err.cancel(),
                     }
-                    Ok(..) => {}
-                    Err(err) => err.cancel(),
-                },
+                }
                 Err(errs) => errs.into_iter().for_each(|err| err.cancel()),
-            }
+            };
 
             // If the user tried to use a key="value" flag, but is missing the quotes, provide
             // a hint about how to resolve this.
@@ -116,9 +127,9 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
     let mut check_cfg = CheckCfg { exhaustive_names, exhaustive_values, ..CheckCfg::default() };
 
     for s in specs {
-        let psess = ParseSess::with_fatal_emitter(
+        let psess = ParseSess::emitter_with_note(
             vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
-            format!("this error occurred on the command line: `--check-cfg={s}`"),
+            format!("this occurred on the command line: `--check-cfg={s}`"),
         );
         let filename = FileName::cfg_spec_source_code(&s);
 
@@ -171,15 +182,17 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
         let mut parser =
             match new_parser_from_source_str(&psess, filename, s.to_string(), StripTokens::Nothing)
             {
-                Ok(parser) => parser,
+                Ok(parser) => parser.recovery(Recovery::Forbidden),
                 Err(errs) => {
                     errs.into_iter().for_each(|err| err.cancel());
                     expected_error();
                 }
             };
 
         let meta_item = match parser.parse_meta_item(AllowLeadingUnsafe::No) {
-            Ok(meta_item) if parser.token == token::Eof => meta_item,
+            Ok(meta_item) if parser.token == token::Eof && parser.dcx().has_errors().is_none() => {
+                meta_item
+            }
             Ok(..) => expected_error(),
             Err(err) => {
                 err.cancel();
@@ -209,6 +222,11 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
                 if values_specified {
                     error!("`cfg()` names cannot be after values");
                 }
+
+                if ident.is_path_segment_keyword() {
+                    error!("malformed `cfg` input, expected a valid identifier");
+                }
+
                 names.push(ident);
             } else if let Some(boolean) = arg.boolean_literal() {
                 if values_specified {

compiler/rustc_parse/src/parser/mod.rs

@@ -466,7 +466,7 @@ impl<'a> Parser<'a> {
 
     // Public for rustfmt usage.
     pub fn parse_ident(&mut self) -> PResult<'a, Ident> {
-        self.parse_ident_common(true)
+        self.parse_ident_common(self.may_recover())
     }
 
     fn parse_ident_common(&mut self, recover: bool) -> PResult<'a, Ident> {

compiler/rustc_session/src/parse.rs

@@ -8,7 +8,7 @@ use rustc_ast::attr::AttrIdGenerator;
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap, FxIndexSet};
 use rustc_data_structures::sync::{AppendOnlyVec, Lock};
-use rustc_errors::emitter::{FatalOnlyEmitter, HumanEmitter, stderr_destination};
+use rustc_errors::emitter::{EmitterWithNote, HumanEmitter, stderr_destination};
 use rustc_errors::translation::Translator;
 use rustc_errors::{
     BufferedEarlyLint, ColorConfig, DecorateDiagCompat, Diag, DiagCtxt, DiagCtxtHandle,
@@ -315,16 +315,12 @@ impl ParseSess {
         }
     }
 
-    pub fn with_fatal_emitter(locale_resources: Vec<&'static str>, fatal_note: String) -> Self {
+    pub fn emitter_with_note(locale_resources: Vec<&'static str>, note: String) -> Self {
         let translator = Translator::with_fallback_bundle(locale_resources, false);
         let sm = Arc::new(SourceMap::new(FilePathMapping::empty()));
-        let fatal_emitter =
+        let emitter =
             Box::new(HumanEmitter::new(stderr_destination(ColorConfig::Auto), translator));
-        let dcx = DiagCtxt::new(Box::new(FatalOnlyEmitter {
-            fatal_emitter,
-            fatal_note: Some(fatal_note),
-        }))
-        .disable_warnings();
+        let dcx = DiagCtxt::new(Box::new(EmitterWithNote { emitter, note }));
         ParseSess::with_dcx(dcx, sm)
     }
 

src/tools/clippy/tests/ui/cast_size.32bit.stderr renamed to src/tools/clippy/tests/ui/cast_size.r32bit.stderr

@@ -1,6 +1,6 @@
-//@revisions: 32bit 64bit
-//@[32bit]ignore-bitwidth: 64
-//@[64bit]ignore-bitwidth: 32
+//@revisions: r32bit r64bit
+//@[r32bit]ignore-bitwidth: 64
+//@[r64bit]ignore-bitwidth: 32
 //@no-rustfix: only some diagnostics have suggestions
 
 #![warn(
@@ -62,7 +62,7 @@ fn main() {
     //~^ cast_precision_loss
     9_999_999_999_999_999usize as f64;
     //~^ cast_precision_loss
-    //~[32bit]^^ ERROR: literal out of range for `usize`
+    //~[r32bit]^^ ERROR: literal out of range for `usize`
     // 999_999_999_999_999_999_999_999_999_999u128 as f128;
 }