Auto merge of #132251 - jieyouxu:rollup-mtv9mpd, r=jieyouxu

Rollup of 7 pull requests

Successful merges:

 - #131633 (error on alignments greater than `isize::MAX`)
 - #132086 (Tweak E0277 highlighting and "long type" path printing)
 - #132220 (Add GUI regression test for doc struct fields margins)
 - #132225 (Dynamically link run-make support)
 - #132227 (Pass constness with span into lower_poly_trait_ref)
 - #132242 (Support `char::is_digit` in const contexts.)
 - #132243 (Remove `ObligationCause::span()` method)

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

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -611,7 +611,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
         Err(terr) => {
             let mut diag = struct_span_code_err!(
                 tcx.dcx(),
-                cause.span(),
+                cause.span,
                 E0053,
                 "method `{}` has an incompatible return type for trait",
                 trait_m.name
@@ -1169,7 +1169,7 @@ fn extract_spans_for_error_reporting<'tcx>(
         TypeError::ArgumentMutability(i) | TypeError::ArgumentSorts(ExpectedFound { .. }, i) => {
             (impl_args.nth(i).unwrap(), trait_args.and_then(|mut args| args.nth(i)))
         }
-        _ => (cause.span(), tcx.hir().span_if_local(trait_m.def_id)),
+        _ => (cause.span, tcx.hir().span_if_local(trait_m.def_id)),
     }
 }
 

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -612,7 +612,7 @@ pub fn check_function_signature<'tcx>(
         match err {
             TypeError::ArgumentMutability(i)
             | TypeError::ArgumentSorts(ExpectedFound { .. }, i) => args.nth(i).unwrap(),
-            _ => cause.span(),
+            _ => cause.span,
         }
     }
 

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

@@ -168,13 +168,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             match hir_bound {
                 hir::GenericBound::Trait(poly_trait_ref) => {
                     let hir::TraitBoundModifiers { constness, polarity } = poly_trait_ref.modifiers;
-                    // FIXME: We could pass these directly into `lower_poly_trait_ref`
-                    // so that we could use these spans in diagnostics within that function...
-                    let constness = match constness {
-                        hir::BoundConstness::Never => None,
-                        hir::BoundConstness::Always(_) => Some(ty::BoundConstness::Const),
-                        hir::BoundConstness::Maybe(_) => Some(ty::BoundConstness::ConstIfConst),
-                    };
                     let polarity = match polarity {
                         rustc_ast::BoundPolarity::Positive => ty::PredicatePolarity::Positive,
                         rustc_ast::BoundPolarity::Negative(_) => ty::PredicatePolarity::Negative,

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs

@@ -50,7 +50,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             } = self.lower_poly_trait_ref(
                 &trait_bound.trait_ref,
                 trait_bound.span,
-                None,
+                hir::BoundConstness::Never,
                 ty::PredicatePolarity::Positive,
                 dummy_self,
                 &mut bounds,

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -658,7 +658,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         &self,
         trait_ref: &hir::TraitRef<'tcx>,
         span: Span,
-        constness: Option<ty::BoundConstness>,
+        constness: hir::BoundConstness,
         polarity: ty::PredicatePolarity,
         self_ty: Ty<'tcx>,
         bounds: &mut Bounds<'tcx>,
@@ -681,11 +681,11 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             Some(self_ty),
         );
 
-        if let Some(constness) = constness
+        if let hir::BoundConstness::Always(span) | hir::BoundConstness::Maybe(span) = constness
             && !self.tcx().is_const_trait(trait_def_id)
         {
             self.dcx().emit_err(crate::errors::ConstBoundForNonConstTrait {
-                span: trait_ref.path.span,
+                span,
                 modifier: constness.as_str(),
             });
         }
@@ -708,7 +708,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 bounds.push_trait_bound(tcx, poly_trait_ref, span, polarity);
 
                 match constness {
-                    Some(ty::BoundConstness::Const) => {
+                    hir::BoundConstness::Always(span) => {
                         if polarity == ty::PredicatePolarity::Positive {
                             bounds.push_const_bound(
                                 tcx,
@@ -718,13 +718,13 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                             );
                         }
                     }
-                    Some(ty::BoundConstness::ConstIfConst) => {
+                    hir::BoundConstness::Maybe(_) => {
                         // We don't emit a const bound here, since that would mean that we
                         // unconditionally need to prove a `HostEffect` predicate, even when
                         // the predicates are being instantiated in a non-const context. This
                         // is instead handled in the `const_conditions` query.
                     }
-                    None => {}
+                    hir::BoundConstness::Never => {}
                 }
             }
             // On the flip side, when filtering `ConstIfConst` bounds, we only need to convert
@@ -734,12 +734,12 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             // here because we only call this on self bounds, and deal with the recursive case
             // in `lower_assoc_item_constraint`.
             PredicateFilter::ConstIfConst | PredicateFilter::SelfConstIfConst => match constness {
-                Some(ty::BoundConstness::ConstIfConst) => {
+                hir::BoundConstness::Maybe(span) => {
                     if polarity == ty::PredicatePolarity::Positive {
                         bounds.push_const_bound(tcx, poly_trait_ref, ty::HostPolarity::Maybe, span);
                     }
                 }
-                None | Some(ty::BoundConstness::Const) => {}
+                hir::BoundConstness::Always(_) | hir::BoundConstness::Never => {}
             },
         }
 

compiler/rustc_hir_typeck/src/_match.rs

@@ -94,14 +94,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 (None, arm.body.span)
             };
 
-            let (span, code) = match prior_arm {
+            let code = match prior_arm {
                 // The reason for the first arm to fail is not that the match arms diverge,
                 // but rather that there's a prior obligation that doesn't hold.
-                None => {
-                    (arm_span, ObligationCauseCode::BlockTailExpression(arm.body.hir_id, match_src))
-                }
-                Some((prior_arm_block_id, prior_arm_ty, prior_arm_span)) => (
-                    expr.span,
+                None => ObligationCauseCode::BlockTailExpression(arm.body.hir_id, match_src),
+                Some((prior_arm_block_id, prior_arm_ty, prior_arm_span)) => {
                     ObligationCauseCode::MatchExpressionArm(Box::new(MatchExpressionArmCause {
                         arm_block_id,
                         arm_span,
@@ -110,13 +107,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         prior_arm_ty,
                         prior_arm_span,
                         scrut_span: scrut.span,
+                        expr_span: expr.span,
                         source: match_src,
                         prior_non_diverging_arms: prior_non_diverging_arms.clone(),
                         tail_defines_return_position_impl_trait,
-                    })),
-                ),
+                    }))
+                }
             };
-            let cause = self.cause(span, code);
+            let cause = self.cause(arm_span, code);
 
             // This is the moral equivalent of `coercion.coerce(self, cause, arm.body, arm_ty)`.
             // We use it this way to be able to expand on the potential error and detect when a

compiler/rustc_hir_typeck/src/expr.rs

@@ -2027,7 +2027,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                     }
                                     Err(_) => {
                                         span_bug!(
-                                            cause.span(),
+                                            cause.span,
                                             "subtyping remaining fields of type changing FRU failed: {target_ty} != {fru_ty}: {}::{}",
                                             variant.name,
                                             ident.name,

compiler/rustc_hir_typeck/src/method/confirm.rs

@@ -550,7 +550,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
                     // This has/will have errored in wfcheck, which we cannot depend on from here, as typeck on functions
                     // may run before wfcheck if the function is used in const eval.
                     self.dcx().span_delayed_bug(
-                        cause.span(),
+                        cause.span,
                         format!("{self_ty} was a subtype of {method_self_ty} but now is not?"),
                     );
                 }

compiler/rustc_middle/src/traits/mod.rs

@@ -92,16 +92,6 @@ impl<'tcx> ObligationCause<'tcx> {
         ObligationCause { span, body_id: CRATE_DEF_ID, code: Default::default() }
     }
 
-    pub fn span(&self) -> Span {
-        match *self.code() {
-            ObligationCauseCode::MatchExpressionArm(box MatchExpressionArmCause {
-                arm_span,
-                ..
-            }) => arm_span,
-            _ => self.span,
-        }
-    }
-
     #[inline]
     pub fn code(&self) -> &ObligationCauseCode<'tcx> {
         &self.code
@@ -517,10 +507,17 @@ pub struct MatchExpressionArmCause<'tcx> {
     pub prior_arm_block_id: Option<HirId>,
     pub prior_arm_ty: Ty<'tcx>,
     pub prior_arm_span: Span,
+    /// Span of the scrutinee of the match (the matched value).
     pub scrut_span: Span,
+    /// Source of the match, i.e. `match` or a desugaring.
     pub source: hir::MatchSource,
+    /// Span of the *whole* match expr.
+    pub expr_span: Span,
+    /// Spans of the previous arms except for those that diverge (i.e. evaluate to `!`).
+    ///
+    /// These are used for pointing out errors that may affect several arms.
     pub prior_non_diverging_arms: Vec<Span>,
-    // Is the expectation of this match expression an RPIT?
+    /// Is the expectation of this match expression an RPIT?
     pub tail_defines_return_position_impl_trait: Option<LocalDefId>,
 }
 

compiler/rustc_passes/messages.ftl

@@ -622,6 +622,10 @@ passes_remove_fields =
 passes_repr_align_function =
     `repr(align)` attributes on functions are unstable
 
+passes_repr_align_greater_than_target_max =
+    alignment must not be greater than `isize::MAX` bytes
+    .note = `isize::MAX` is {$size} for the current target
+
 passes_repr_conflicting =
     conflicting representation hints
 

compiler/rustc_passes/src/check_attr.rs

@@ -34,6 +34,7 @@ use rustc_session::lint::builtin::{
 use rustc_session::parse::feature_err;
 use rustc_span::symbol::{Symbol, kw, sym};
 use rustc_span::{BytePos, DUMMY_SP, Span};
+use rustc_target::abi::Size;
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::infer::{TyCtxtInferExt, ValuePairs};
@@ -1785,7 +1786,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         | Target::Union
                         | Target::Enum
                         | Target::Fn
-                        | Target::Method(_) => continue,
+                        | Target::Method(_) => {}
                         _ => {
                             self.dcx().emit_err(
                                 errors::AttrApplication::StructEnumFunctionMethodUnion {
@@ -1795,6 +1796,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             );
                         }
                     }
+
+                    self.check_align_value(hint);
                 }
                 sym::packed => {
                     if target != Target::Struct && target != Target::Union {
@@ -1892,6 +1895,45 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
+    fn check_align_value(&self, item: &MetaItemInner) {
+        match item.singleton_lit_list() {
+            Some((
+                _,
+                MetaItemLit {
+                    kind: ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed), ..
+                },
+            )) => {
+                let val = literal.get() as u64;
+                if val > 2_u64.pow(29) {
+                    // for values greater than 2^29, a different error will be emitted, make sure that happens
+                    self.dcx().span_delayed_bug(
+                        item.span(),
+                        "alignment greater than 2^29 should be errored on elsewhere",
+                    );
+                } else {
+                    // only do this check when <= 2^29 to prevent duplicate errors:
+                    // alignment greater than 2^29 not supported
+                    // alignment is too large for the current target
+
+                    let max =
+                        Size::from_bits(self.tcx.sess.target.pointer_width).signed_int_max() as u64;
+                    if val > max {
+                        self.dcx().emit_err(errors::InvalidReprAlignForTarget {
+                            span: item.span(),
+                            size: max,
+                        });
+                    }
+                }
+            }
+
+            // if the attribute is malformed, singleton_lit_list may not be of the expected type or may be None
+            // but an error will have already been emitted, so this code should just skip such attributes
+            Some((_, _)) | None => {
+                self.dcx().span_delayed_bug(item.span(), "malformed repr(align(N))");
+            }
+        }
+    }
+
     fn check_used(&self, attrs: &[Attribute], target: Target, target_span: Span) {
         let mut used_linker_span = None;
         let mut used_compiler_span = None;

compiler/rustc_passes/src/errors.rs

@@ -567,6 +567,15 @@ pub(crate) struct ReprConflicting {
     pub hint_spans: Vec<Span>,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_repr_align_greater_than_target_max, code = E0589)]
+#[note]
+pub(crate) struct InvalidReprAlignForTarget {
+    #[primary_span]
+    pub span: Span,
+    pub size: u64,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(passes_repr_conflicting, code = E0566)]
 pub(crate) struct ReprConflictingLint;

compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs

@@ -392,7 +392,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                         Some(ty) if expected == ty => {
                             let source_map = self.tcx.sess.source_map();
                             err.span_suggestion(
-                                source_map.end_point(cause.span()),
+                                source_map.end_point(cause.span),
                                 "try removing this `?`",
                                 "",
                                 Applicability::MachineApplicable,
@@ -412,6 +412,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 source,
                 ref prior_non_diverging_arms,
                 scrut_span,
+                expr_span,
                 ..
             }) => match source {
                 hir::MatchSource::TryDesugar(scrut_hir_id) => {
@@ -430,7 +431,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             Some(ty) if expected == ty => {
                                 let source_map = self.tcx.sess.source_map();
                                 err.span_suggestion(
-                                    source_map.end_point(cause.span()),
+                                    source_map.end_point(cause.span),
                                     "try removing this `?`",
                                     "",
                                     Applicability::MachineApplicable,
@@ -460,12 +461,12 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             format!("this and all prior arms are found to be of type `{t}`"),
                         );
                     }
-                    let outer = if any_multiline_arm || !source_map.is_multiline(cause.span) {
+                    let outer = if any_multiline_arm || !source_map.is_multiline(expr_span) {
                         // Cover just `match` and the scrutinee expression, not
                         // the entire match body, to reduce diagram noise.
-                        cause.span.shrink_to_lo().to(scrut_span)
+                        expr_span.shrink_to_lo().to(scrut_span)
                     } else {
-                        cause.span
+                        expr_span
                     };
                     let msg = "`match` arms have incompatible types";
                     err.span_label(outer, msg);
@@ -1148,7 +1149,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         terr: TypeError<'tcx>,
         prefer_label: bool,
     ) {
-        let span = cause.span();
+        let span = cause.span;
 
         // For some types of errors, expected-found does not make
         // sense, so just ignore the values we were given.
@@ -1642,7 +1643,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         terr: TypeError<'tcx>,
     ) -> Vec<TypeErrorAdditionalDiags> {
         let mut suggestions = Vec::new();
-        let span = trace.cause.span();
+        let span = trace.cause.span;
         let values = self.resolve_vars_if_possible(trace.values);
         if let Some((expected, found)) = values.ty() {
             match (expected.kind(), found.kind()) {
@@ -1792,7 +1793,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
     ) -> Diag<'a> {
         debug!("report_and_explain_type_error(trace={:?}, terr={:?})", trace, terr);
 
-        let span = trace.cause.span();
+        let span = trace.cause.span;
         let failure_code = trace.cause.as_failure_code_diag(
             terr,
             span,

compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/placeholder_error.rs

@@ -237,7 +237,7 @@ impl<'tcx> NiceRegionError<'_, 'tcx> {
         expected_args: GenericArgsRef<'tcx>,
         actual_args: GenericArgsRef<'tcx>,
     ) -> Diag<'tcx> {
-        let span = cause.span();
+        let span = cause.span;
 
         let (leading_ellipsis, satisfy_span, where_span, dup_span, def_id) =
             if let ObligationCauseCode::WhereClause(def_id, span)