Auto merge of #100708 - matthiaskrgr:rollup-vl0olnj, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #97962 (Make must_not_suspend lint see through references when drop tracking is enabled)
 - #99966 (avoid assertion failures in try_to_scalar_int)
 - #100637 (Improving Fuchsia rustc support documentation)
 - #100643 (Point at a type parameter shadowing another type)
 - #100651 (Migrations for rustc_expand transcribe.rs)
 - #100669 (Attribute cleanups)
 - #100670 (Fix documentation of rustc_parse::parser::Parser::parse_stmt_without_recovery)
 - #100674 (Migrate lint reports in typeck::check_unused to LintDiagnostic)
 - #100688 (`ty::Error` does not match other types for region constraints)

Failed merges:

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

compiler/rustc_builtin_macros/src/deriving/bounds.rs

@@ -15,7 +15,6 @@ pub fn expand_deriving_copy(
 ) {
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: path_std!(marker::Copy),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/clone.rs

@@ -71,7 +71,6 @@ pub fn expand_deriving_clone(
     let attrs = vec![cx.attribute(inline)];
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: path_std!(clone::Clone),
         additional_bounds: bounds,
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs

@@ -23,7 +23,6 @@ pub fn expand_deriving_eq(
     let attrs = vec![cx.attribute(inline), cx.attribute(doc), cx.attribute(no_coverage)];
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: path_std!(cmp::Eq),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs

@@ -18,7 +18,6 @@ pub fn expand_deriving_ord(
     let attrs = vec![cx.attribute(inline)];
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: path_std!(cmp::Ord),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs

@@ -98,7 +98,6 @@ pub fn expand_deriving_partial_eq(
 
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: path_std!(cmp::PartialEq),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs

@@ -36,7 +36,6 @@ pub fn expand_deriving_partial_ord(
 
     let trait_def = TraitDef {
         span,
-        attributes: vec![],
         path: path_std!(cmp::PartialOrd),
         additional_bounds: vec![],
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/debug.rs

@@ -19,7 +19,6 @@ pub fn expand_deriving_debug(
 
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: path_std!(fmt::Debug),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/decodable.rs

@@ -22,7 +22,6 @@ pub fn expand_deriving_rustc_decodable(
 
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: Path::new_(vec![krate, sym::Decodable], vec![], PathKind::Global),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/default.rs

@@ -25,7 +25,6 @@ pub fn expand_deriving_default(
     let attrs = vec![cx.attribute(inline)];
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: Path::new(vec![kw::Default, sym::Default]),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/encodable.rs

@@ -106,7 +106,6 @@ pub fn expand_deriving_rustc_encodable(
 
     let trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path: Path::new_(vec![krate, sym::Encodable], vec![], PathKind::Global),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -184,8 +184,6 @@ pub struct TraitDef<'a> {
     /// The span for the current #[derive(Foo)] header.
     pub span: Span,
 
-    pub attributes: Vec<ast::Attribute>,
-
     /// Path of the trait, including any type parameters
     pub path: Path,
 
@@ -605,7 +603,7 @@ impl<'a> TraitDef<'a> {
                         param.bounds.iter().cloned()
                     ).collect();
 
-                cx.typaram(param.ident.span.with_ctxt(ctxt), param.ident, vec![], bounds, None)
+                cx.typaram(param.ident.span.with_ctxt(ctxt), param.ident, bounds, None)
             }
             GenericParamKind::Const { ty, kw_span, .. } => {
                 let const_nodefault_kind = GenericParamKind::Const {
@@ -718,15 +716,13 @@ impl<'a> TraitDef<'a> {
         let self_type = cx.ty_path(path);
 
         let attr = cx.attribute(cx.meta_word(self.span, sym::automatically_derived));
+        let attrs = vec![attr];
         let opt_trait_ref = Some(trait_ref);
 
-        let mut a = vec![attr];
-        a.extend(self.attributes.iter().cloned());
-
         cx.item(
             self.span,
             Ident::empty(),
-            a,
+            attrs,
             ast::ItemKind::Impl(Box::new(ast::Impl {
                 unsafety: ast::Unsafe::No,
                 polarity: ast::ImplPolarity::Positive,

compiler/rustc_builtin_macros/src/deriving/generic/ty.rs

@@ -146,7 +146,6 @@ fn mk_ty_param(
     cx: &ExtCtxt<'_>,
     span: Span,
     name: Symbol,
-    attrs: &[ast::Attribute],
     bounds: &[Path],
     self_ident: Ident,
     self_generics: &Generics,
@@ -158,7 +157,7 @@ fn mk_ty_param(
             cx.trait_bound(path)
         })
         .collect();
-    cx.typaram(span, Ident::new(name, span), attrs.to_owned(), bounds, None)
+    cx.typaram(span, Ident::new(name, span), bounds, None)
 }
 
 /// Bounds on type parameters.
@@ -183,7 +182,7 @@ impl Bounds {
             .iter()
             .map(|t| {
                 let (name, ref bounds) = *t;
-                mk_ty_param(cx, span, name, &[], &bounds, self_ty, self_generics)
+                mk_ty_param(cx, span, name, &bounds, self_ty, self_generics)
             })
             .collect();
 

compiler/rustc_builtin_macros/src/deriving/hash.rs

@@ -21,7 +21,6 @@ pub fn expand_deriving_hash(
     let arg = Path::new_local(typaram);
     let hash_trait_def = TraitDef {
         span,
-        attributes: Vec::new(),
         path,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),

compiler/rustc_error_messages/locales/en-US/expand.ftl

@@ -3,3 +3,20 @@ expand_explain_doc_comment_outer =
 
 expand_explain_doc_comment_inner =
     inner doc comments expand to `#![doc = "..."]`, which is what this macro attempted to match
+
+expand_expr_repeat_no_syntax_vars = 
+    attempted to repeat an expression containing no syntax variables matched as repeating at this depth
+
+expand_must_repeat_once = 
+    this must repeat at least once
+
+expand_count_repetition_misplaced =
+    `count` can not be placed inside the inner-most repetition
+
+expand_meta_var_expr_unrecognized_var =
+    variable `{$key}` is not recognized in meta-variable expression
+
+expand_var_still_repeating =
+    variable '{$ident}' is still repeating at this depth
+
+expand_meta_var_dif_seq_matchers = {$msg}

compiler/rustc_error_messages/locales/en-US/typeck.ftl

@@ -123,3 +123,11 @@ typeck_manual_implementation =
     .help = add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 typeck_substs_on_overridden_impl = could not resolve substs on overridden impl
+
+typeck_unused_extern_crate =
+    unused extern crate
+    .suggestion = remove it
+
+typeck_extern_crate_not_idiomatic =
+    `extern crate` is not idiomatic in the new edition
+    .suggestion = convert it to a `{$msg_code}`

compiler/rustc_errors/src/diagnostic.rs

@@ -8,7 +8,7 @@ use rustc_error_messages::FluentValue;
 use rustc_hir as hir;
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_span::edition::LATEST_STABLE_EDITION;
-use rustc_span::symbol::{Ident, Symbol};
+use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
 use rustc_span::{edition::Edition, Span, DUMMY_SP};
 use std::borrow::Cow;
 use std::fmt;
@@ -87,6 +87,7 @@ into_diagnostic_arg_using_display!(
     hir::Target,
     Edition,
     Ident,
+    MacroRulesNormalizedIdent,
 );
 
 impl IntoDiagnosticArg for bool {

compiler/rustc_expand/src/build.rs

@@ -107,14 +107,13 @@ impl<'a> ExtCtxt<'a> {
         &self,
         span: Span,
         ident: Ident,
-        attrs: Vec<ast::Attribute>,
         bounds: ast::GenericBounds,
         default: Option<P<ast::Ty>>,
     ) -> ast::GenericParam {
         ast::GenericParam {
             ident: ident.with_span_pos(span),
             id: ast::DUMMY_NODE_ID,
-            attrs: attrs.into(),
+            attrs: AttrVec::new(),
             bounds,
             kind: ast::GenericParamKind::Type { default },
             is_placeholder: false,

compiler/rustc_expand/src/errors.rs

@@ -0,0 +1,48 @@
+use rustc_macros::SessionDiagnostic;
+use rustc_span::symbol::MacroRulesNormalizedIdent;
+use rustc_span::Span;
+
+#[derive(SessionDiagnostic)]
+#[error(expand::expr_repeat_no_syntax_vars)]
+pub(crate) struct NoSyntaxVarsExprRepeat {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[error(expand::must_repeat_once)]
+pub(crate) struct MustRepeatOnce {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[error(expand::count_repetition_misplaced)]
+pub(crate) struct CountRepetitionMisplaced {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[error(expand::meta_var_expr_unrecognized_var)]
+pub(crate) struct MetaVarExprUnrecognizedVar {
+    #[primary_span]
+    pub span: Span,
+    pub key: MacroRulesNormalizedIdent,
+}
+
+#[derive(SessionDiagnostic)]
+#[error(expand::var_still_repeating)]
+pub(crate) struct VarStillRepeating {
+    #[primary_span]
+    pub span: Span,
+    pub ident: MacroRulesNormalizedIdent,
+}
+
+#[derive(SessionDiagnostic)]
+#[error(expand::meta_var_dif_seq_matchers)]
+pub(crate) struct MetaVarsDifSeqMatchers {
+    #[primary_span]
+    pub span: Span,
+    pub msg: String,
+}

compiler/rustc_expand/src/lib.rs

@@ -25,6 +25,7 @@ pub mod base;
 pub mod build;
 #[macro_use]
 pub mod config;
+pub mod errors;
 pub mod expand;
 pub mod module;
 pub mod proc_macro;

compiler/rustc_expand/src/mbe/transcribe.rs

@@ -1,4 +1,8 @@
 use crate::base::ExtCtxt;
+use crate::errors::{
+    CountRepetitionMisplaced, MetaVarExprUnrecognizedVar, MetaVarsDifSeqMatchers, MustRepeatOnce,
+    NoSyntaxVarsExprRepeat, VarStillRepeating,
+};
 use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, MatchedTokenTree, NamedMatch};
 use crate::mbe::{self, MetaVarExpr};
 use rustc_ast::mut_visit::{self, MutVisitor};
@@ -165,19 +169,15 @@ pub(super) fn transcribe<'a>(
             seq @ mbe::TokenTree::Sequence(_, delimited) => {
                 match lockstep_iter_size(&seq, interp, &repeats) {
                     LockstepIterSize::Unconstrained => {
-                        return Err(cx.struct_span_err(
-                            seq.span(), /* blame macro writer */
-                            "attempted to repeat an expression containing no syntax variables \
-                             matched as repeating at this depth",
-                        ));
+                        return Err(cx.create_err(NoSyntaxVarsExprRepeat { span: seq.span() }));
                     }
 
                     LockstepIterSize::Contradiction(msg) => {
                         // FIXME: this really ought to be caught at macro definition time... It
                         // happens when two meta-variables are used in the same repetition in a
                         // sequence, but they come from different sequence matchers and repeat
                         // different amounts.
-                        return Err(cx.struct_span_err(seq.span(), &msg));
+                        return Err(cx.create_err(MetaVarsDifSeqMatchers { span: seq.span(), msg }));
                     }
 
                     LockstepIterSize::Constraint(len, _) => {
@@ -193,10 +193,7 @@ pub(super) fn transcribe<'a>(
                                 // FIXME: this really ought to be caught at macro definition
                                 // time... It happens when the Kleene operator in the matcher and
                                 // the body for the same meta-variable do not match.
-                                return Err(cx.struct_span_err(
-                                    sp.entire(),
-                                    "this must repeat at least once",
-                                ));
+                                return Err(cx.create_err(MustRepeatOnce { span: sp.entire() }));
                             }
                         } else {
                             // 0 is the initial counter (we have done 0 repetitions so far). `len`
@@ -239,10 +236,7 @@ pub(super) fn transcribe<'a>(
                         }
                         MatchedSeq(..) => {
                             // We were unable to descend far enough. This is an error.
-                            return Err(cx.struct_span_err(
-                                sp, /* blame the macro writer */
-                                &format!("variable '{}' is still repeating at this depth", ident),
-                            ));
+                            return Err(cx.create_err(VarStillRepeating { span: sp, ident }));
                         }
                     }
                 } else {
@@ -448,10 +442,7 @@ fn count_repetitions<'a>(
         match matched {
             MatchedTokenTree(_) | MatchedNonterminal(_) => {
                 if declared_lhs_depth == 0 {
-                    return Err(cx.struct_span_err(
-                        sp.entire(),
-                        "`count` can not be placed inside the inner-most repetition",
-                    ));
+                    return Err(cx.create_err(CountRepetitionMisplaced { span: sp.entire() }));
                 }
                 match depth_opt {
                     None => Ok(1),
@@ -499,12 +490,7 @@ where
 {
     let span = ident.span;
     let key = MacroRulesNormalizedIdent::new(ident);
-    interp.get(&key).ok_or_else(|| {
-        cx.struct_span_err(
-            span,
-            &format!("variable `{}` is not recognized in meta-variable expression", key),
-        )
-    })
+    interp.get(&key).ok_or_else(|| cx.create_err(MetaVarExprUnrecognizedVar { span, key }))
 }
 
 /// Used by meta-variable expressions when an user input is out of the actual declared bounds. For

compiler/rustc_infer/src/infer/outlives/test_type_match.rs

@@ -174,7 +174,14 @@ impl<'tcx> TypeRelation<'tcx> for Match<'tcx> {
 
     #[instrument(skip(self), level = "debug")]
     fn tys(&mut self, pattern: Ty<'tcx>, value: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
-        if pattern == value { Ok(pattern) } else { relate::super_relate_tys(self, pattern, value) }
+        if let ty::Error(_) = pattern.kind() {
+            // Unlike normal `TypeRelation` rules, `ty::Error` does not equal any type.
+            self.no_match()
+        } else if pattern == value {
+            Ok(pattern)
+        } else {
+            relate::super_relate_tys(self, pattern, value)
+        }
     }
 
     #[instrument(skip(self), level = "debug")]

compiler/rustc_middle/src/mir/interpret/value.rs

@@ -79,7 +79,7 @@ impl<'tcx> ConstValue<'tcx> {
     }
 
     pub fn try_to_scalar_int(&self) -> Option<ScalarInt> {
-        Some(self.try_to_scalar()?.assert_int())
+        self.try_to_scalar()?.try_to_int().ok()
     }
 
     pub fn try_to_bits(&self, size: Size) -> Option<u128> {
@@ -368,6 +368,7 @@ impl<'tcx, Prov: Provenance> Scalar<Prov> {
     }
 
     #[inline(always)]
+    #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980)
     pub fn assert_int(self) -> ScalarInt {
         self.try_to_int().unwrap()
     }
@@ -389,6 +390,7 @@ impl<'tcx, Prov: Provenance> Scalar<Prov> {
     }
 
     #[inline(always)]
+    #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980)
     pub fn assert_bits(self, target_size: Size) -> u128 {
         self.to_bits(target_size).unwrap()
     }