Auto merge of rust-lang#116848 - matthiaskrgr:rollup-y4e025o, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#116717 (Special case iterator chain checks for suggestion)
 - rust-lang#116719 (Add MonoItems and Instance to stable_mir)
 - rust-lang#116787 (Implement an internal lint encouraging use of `Span::eq_ctxt`)
 - rust-lang#116827 (Make `handle_options` public again.)
 - rust-lang#116838 (Fix duplicate labels emitted in `render_multispan_macro_backtrace()`)

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

Author: bors

compiler/rustc_driver_impl/src/lib.rs

@@ -1185,7 +1185,11 @@ fn print_flag_list<T>(
 ///
 /// So with all that in mind, the comments below have some more detail about the
 /// contortions done here to get things to work out correctly.
-fn handle_options(handler: &EarlyErrorHandler, args: &[String]) -> Option<getopts::Matches> {
+///
+/// This does not need to be `pub` for rustc itself, but @chaosite needs it to
+/// be public when using rustc as a library, see
+/// <https://github.com/rust-lang/rust/commit/2b4c33817a5aaecabf4c6598d41e190080ec119e>
+pub fn handle_options(handler: &EarlyErrorHandler, args: &[String]) -> Option<getopts::Matches> {
     if args.is_empty() {
         // user did not write `-v` nor `-Z unstable-options`, so do not
         // include that extra information.

compiler/rustc_errors/src/emitter.rs

@@ -23,7 +23,7 @@ use crate::{
 use rustc_lint_defs::pluralize;
 
 use derive_setters::Setters;
-use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
+use rustc_data_structures::fx::{FxHashMap, FxIndexMap, FxIndexSet};
 use rustc_data_structures::sync::{DynSend, IntoDynSyncSend, Lrc};
 use rustc_error_messages::{FluentArgs, SpanLabel};
 use rustc_span::hygiene::{ExpnKind, MacroKind};
@@ -370,7 +370,7 @@ pub trait Emitter: Translate {
     }
 
     fn render_multispan_macro_backtrace(&self, span: &mut MultiSpan, always_backtrace: bool) {
-        let mut new_labels: Vec<(Span, String)> = vec![];
+        let mut new_labels = FxIndexSet::default();
 
         for &sp in span.primary_spans() {
             if sp.is_dummy() {
@@ -387,7 +387,7 @@ pub trait Emitter: Translate {
                 }
 
                 if always_backtrace {
-                    new_labels.push((
+                    new_labels.insert((
                         trace.def_site,
                         format!(
                             "in this expansion of `{}`{}",
@@ -431,7 +431,7 @@ pub trait Emitter: Translate {
                             format!("this {} desugaring", kind.descr()).into()
                         }
                     };
-                    new_labels.push((
+                    new_labels.insert((
                         trace.call_site,
                         format!(
                             "in {}{}",

compiler/rustc_hir_typeck/src/callee.rs

@@ -650,7 +650,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .sess
                 .source_map()
                 .is_multiline(call_expr.span.with_lo(callee_expr.span.hi()))
-                && call_expr.span.ctxt() == callee_expr.span.ctxt();
+                && call_expr.span.eq_ctxt(callee_expr.span);
             if call_is_multiline {
                 err.span_suggestion(
                     callee_expr.span.shrink_to_hi(),

compiler/rustc_lint/messages.ftl

@@ -494,6 +494,8 @@ lint_renamed_lint = lint `{$name}` has been renamed to `{$replace}`
 
 lint_requested_level = requested on the command line with `{$level} {$lint_name}`
 
+lint_span_use_eq_ctxt = use `.eq_ctxt()` instead of `.ctxt() == .ctxt()`
+
 lint_supertrait_as_deref_target = `{$t}` implements `Deref` with supertrait `{$target_principal}` as target
     .label = target type is set here
 

compiler/rustc_lint/src/internal.rs

@@ -3,14 +3,14 @@
 
 use crate::lints::{
     BadOptAccessDiag, DefaultHashTypesDiag, DiagOutOfImpl, LintPassByHand, NonExistentDocKeyword,
-    QueryInstability, TyQualified, TykindDiag, TykindKind, UntranslatableDiag,
+    QueryInstability, SpanUseEqCtxtDiag, TyQualified, TykindDiag, TykindKind, UntranslatableDiag,
     UntranslatableDiagnosticTrivial,
 };
 use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext};
 use rustc_ast as ast;
 use rustc_hir::def::Res;
 use rustc_hir::{def_id::DefId, Expr, ExprKind, GenericArg, PatKind, Path, PathSegment, QPath};
-use rustc_hir::{HirId, Impl, Item, ItemKind, Node, Pat, Ty, TyKind};
+use rustc_hir::{BinOp, BinOpKind, HirId, Impl, Item, ItemKind, Node, Pat, Ty, TyKind};
 use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::hygiene::{ExpnKind, MacroKind};
@@ -537,3 +537,33 @@ impl LateLintPass<'_> for BadOptAccess {
         }
     }
 }
+
+declare_tool_lint! {
+    pub rustc::SPAN_USE_EQ_CTXT,
+    Allow,
+    "forbid uses of `==` with `Span::ctxt`, suggest `Span::eq_ctxt` instead",
+    report_in_external_macro: true
+}
+
+declare_lint_pass!(SpanUseEqCtxt => [SPAN_USE_EQ_CTXT]);
+
+impl<'tcx> LateLintPass<'tcx> for SpanUseEqCtxt {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'_>) {
+        if let ExprKind::Binary(BinOp { node: BinOpKind::Eq, .. }, lhs, rhs) = expr.kind {
+            if is_span_ctxt_call(cx, lhs) && is_span_ctxt_call(cx, rhs) {
+                cx.emit_spanned_lint(SPAN_USE_EQ_CTXT, expr.span, SpanUseEqCtxtDiag);
+            }
+        }
+    }
+}
+
+fn is_span_ctxt_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+    match &expr.kind {
+        ExprKind::MethodCall(..) => cx
+            .typeck_results()
+            .type_dependent_def_id(expr.hir_id)
+            .is_some_and(|call_did| cx.tcx.is_diagnostic_item(sym::SpanCtxt, call_did)),
+
+        _ => false,
+    }
+}

compiler/rustc_lint/src/lib.rs

@@ -531,6 +531,8 @@ fn register_internals(store: &mut LintStore) {
     store.register_late_mod_pass(|_| Box::new(BadOptAccess));
     store.register_lints(&PassByValue::get_lints());
     store.register_late_mod_pass(|_| Box::new(PassByValue));
+    store.register_lints(&SpanUseEqCtxt::get_lints());
+    store.register_late_mod_pass(|_| Box::new(SpanUseEqCtxt));
     // FIXME(davidtwco): deliberately do not include `UNTRANSLATABLE_DIAGNOSTIC` and
     // `DIAGNOSTIC_OUTSIDE_OF_IMPL` here because `-Wrustc::internal` is provided to every crate and
     // these lints will trigger all of the time - change this once migration to diagnostic structs
@@ -548,6 +550,7 @@ fn register_internals(store: &mut LintStore) {
             LintId::of(USAGE_OF_QUALIFIED_TY),
             LintId::of(EXISTING_DOC_KEYWORD),
             LintId::of(BAD_OPT_ACCESS),
+            LintId::of(SPAN_USE_EQ_CTXT),
         ],
     );
 }

compiler/rustc_lint/src/lints.rs

@@ -900,6 +900,10 @@ pub struct QueryInstability {
     pub query: Symbol,
 }
 
+#[derive(LintDiagnostic)]
+#[diag(lint_span_use_eq_ctxt)]
+pub struct SpanUseEqCtxtDiag;
+
 #[derive(LintDiagnostic)]
 #[diag(lint_tykind_kind)]
 pub struct TykindKind {

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -404,7 +404,7 @@ impl<'a> CoverageSpansGenerator<'a> {
 
         let Some(visible_macro) = curr.visible_macro(self.body_span) else { return };
         if let Some(prev) = &self.some_prev
-            && prev.expn_span.ctxt() == curr.expn_span.ctxt()
+            && prev.expn_span.eq_ctxt(curr.expn_span)
         {
             return;
         }

compiler/rustc_passes/src/loops.rs

@@ -231,7 +231,7 @@ impl<'a, 'hir> CheckLoopVisitor<'a, 'hir> {
             AsyncClosure(closure_span) => {
                 self.sess.emit_err(BreakInsideAsyncBlock { span, closure_span, name });
             }
-            UnlabeledBlock(block_span) if is_break && block_span.ctxt() == break_span.ctxt() => {
+            UnlabeledBlock(block_span) if is_break && block_span.eq_ctxt(break_span) => {
                 let suggestion = Some(OutsideLoopSuggestion { block_span, break_span });
                 self.sess.emit_err(OutsideLoop { span, name, is_break, suggestion });
             }

compiler/rustc_smir/src/rustc_internal/mod.rs

@@ -6,9 +6,11 @@
 use crate::rustc_internal;
 use crate::rustc_smir::Tables;
 use rustc_data_structures::fx;
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_driver::{Callbacks, Compilation, RunCompiler};
 use rustc_interface::{interface, Queries};
 use rustc_middle::mir::interpret::AllocId;
+use rustc_middle::ty;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::def_id::{CrateNum, DefId};
 use rustc_span::Span;
@@ -97,7 +99,7 @@ impl<'tcx> Tables<'tcx> {
         stable_mir::ty::Prov(self.create_alloc_id(aid))
     }
 
-    fn create_def_id(&mut self, did: DefId) -> stable_mir::DefId {
+    pub(crate) fn create_def_id(&mut self, did: DefId) -> stable_mir::DefId {
         self.def_ids.create_or_fetch(did)
     }
 
@@ -108,6 +110,17 @@ impl<'tcx> Tables<'tcx> {
     pub(crate) fn create_span(&mut self, span: Span) -> stable_mir::ty::Span {
         self.spans.create_or_fetch(span)
     }
+
+    pub(crate) fn instance_def(
+        &mut self,
+        instance: ty::Instance<'tcx>,
+    ) -> stable_mir::mir::mono::InstanceDef {
+        self.instances.create_or_fetch(instance)
+    }
+
+    pub(crate) fn static_def(&mut self, did: DefId) -> stable_mir::mir::mono::StaticDef {
+        stable_mir::mir::mono::StaticDef(self.create_def_id(did))
+    }
 }
 
 pub fn crate_num(item: &stable_mir::Crate) -> CrateNum {
@@ -118,10 +131,11 @@ pub fn run(tcx: TyCtxt<'_>, f: impl FnOnce()) {
     stable_mir::run(
         Tables {
             tcx,
-            def_ids: rustc_internal::IndexMap { index_map: fx::FxIndexMap::default() },
-            alloc_ids: rustc_internal::IndexMap { index_map: fx::FxIndexMap::default() },
-            spans: rustc_internal::IndexMap { index_map: fx::FxIndexMap::default() },
+            def_ids: IndexMap::default(),
+            alloc_ids: IndexMap::default(),
+            spans: IndexMap::default(),
             types: vec![],
+            instances: IndexMap::default(),
         },
         f,
     );
@@ -192,6 +206,12 @@ pub struct IndexMap<K, V> {
     index_map: fx::FxIndexMap<K, V>,
 }
 
+impl<K, V> Default for IndexMap<K, V> {
+    fn default() -> Self {
+        Self { index_map: FxIndexMap::default() }
+    }
+}
+
 impl<K: PartialEq + Hash + Eq, V: Copy + Debug + PartialEq + IndexedVal> IndexMap<K, V> {
     pub fn create_or_fetch(&mut self, key: K) -> V {
         let len = self.index_map.len();