diff options
Diffstat (limited to '')
| -rw-r--r-- | compiler/rustc_typeck/src/check/check.rs | 195 |
1 files changed, 118 insertions, 77 deletions
diff --git a/compiler/rustc_typeck/src/check/check.rs b/compiler/rustc_typeck/src/check/check.rs index 9c1fd9b30..d6fa74c87 100644 --- a/compiler/rustc_typeck/src/check/check.rs +++ b/compiler/rustc_typeck/src/check/check.rs @@ -18,6 +18,7 @@ use rustc_infer::infer::{DefiningAnchor, RegionVariableOrigin, TyCtxtInferExt}; use rustc_infer::traits::Obligation; use rustc_lint::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS; use rustc_middle::hir::nested_filter; +use rustc_middle::middle::stability::EvalResult; use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES}; use rustc_middle::ty::subst::GenericArgKind; use rustc_middle::ty::util::{Discr, IntTypeExt}; @@ -32,7 +33,6 @@ use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _; use rustc_trait_selection::traits::{self, ObligationCtxt}; use rustc_ty_utils::representability::{self, Representability}; -use std::iter; use std::ops::ControlFlow; pub(super) fn check_abi(tcx: TyCtxt<'_>, hir_id: hir::HirId, span: Span, abi: Abi) { @@ -101,12 +101,11 @@ pub(super) fn check_fn<'a, 'tcx>( decl.output.span(), param_env, )); - // If we replaced declared_ret_ty with infer vars, then we must be infering + // If we replaced declared_ret_ty with infer vars, then we must be inferring // an opaque type, so set a flag so we can improve diagnostics. fcx.return_type_has_opaque = ret_ty != declared_ret_ty; fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(ret_ty))); - fcx.ret_type_span = Some(decl.output.span()); let span = body.value.span; @@ -610,12 +609,7 @@ pub(super) fn check_opaque_for_inheriting_lifetimes<'tcx>( fn visit_ty(&mut self, arg: &'tcx hir::Ty<'tcx>) { match arg.kind { hir::TyKind::Path(hir::QPath::Resolved(None, path)) => match &path.segments { - [ - PathSegment { - res: Some(Res::SelfTy { trait_: _, alias_to: impl_ref }), - .. - }, - ] => { + [PathSegment { res: Res::SelfTy { trait_: _, alias_to: impl_ref }, .. }] => { let impl_ty_name = impl_ref.map(|(def_id, _)| self.tcx.def_path_str(def_id)); self.selftys.push((path.span, impl_ty_name)); @@ -1104,12 +1098,28 @@ fn check_impl_items_against_trait<'tcx>( missing_items.push(tcx.associated_item(trait_item_id)); } - if let Some(required_items) = &must_implement_one_of { - // true if this item is specifically implemented in this impl - let is_implemented_here = ancestors - .leaf_def(tcx, trait_item_id) - .map_or(false, |node_item| !node_item.defining_node.is_from_trait()); + // true if this item is specifically implemented in this impl + let is_implemented_here = ancestors + .leaf_def(tcx, trait_item_id) + .map_or(false, |node_item| !node_item.defining_node.is_from_trait()); + + if !is_implemented_here { + match tcx.eval_default_body_stability(trait_item_id, full_impl_span) { + EvalResult::Deny { feature, reason, issue, .. } => default_body_is_unstable( + tcx, + full_impl_span, + trait_item_id, + feature, + reason, + issue, + ), + // Unmarked default bodies are considered stable (at least for now). + EvalResult::Allow | EvalResult::Unmarked => {} + } + } + + if let Some(required_items) = &must_implement_one_of { if is_implemented_here { let trait_item = tcx.associated_item(trait_item_id); if required_items.contains(&trait_item.ident(tcx)) { @@ -1448,7 +1458,7 @@ fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, vs: &'tcx [hir::Variant<'tcx>], def_id: L def.destructor(tcx); // force the destructor to be evaluated if vs.is_empty() { - if let Some(attr) = tcx.get_attr(def_id.to_def_id(), sym::repr) { + if let Some(attr) = tcx.get_attrs(def_id.to_def_id(), sym::repr).next() { struct_span_err!( tcx.sess, attr.span, @@ -1494,76 +1504,107 @@ fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, vs: &'tcx [hir::Variant<'tcx>], def_id: L } } - let mut disr_vals: Vec<Discr<'tcx>> = Vec::with_capacity(vs.len()); - // This tracks the previous variant span (in the loop) incase we need it for diagnostics - let mut prev_variant_span: Span = DUMMY_SP; - for ((_, discr), v) in iter::zip(def.discriminants(tcx), vs) { - // Check for duplicate discriminant values - if let Some(i) = disr_vals.iter().position(|&x| x.val == discr.val) { - let variant_did = def.variant(VariantIdx::new(i)).def_id; - let variant_i_hir_id = tcx.hir().local_def_id_to_hir_id(variant_did.expect_local()); - let variant_i = tcx.hir().expect_variant(variant_i_hir_id); - let i_span = match variant_i.disr_expr { - Some(ref expr) => tcx.hir().span(expr.hir_id), - None => tcx.def_span(variant_did), - }; - let span = match v.disr_expr { - Some(ref expr) => tcx.hir().span(expr.hir_id), - None => v.span, - }; - let display_discr = format_discriminant_overflow(tcx, v, discr); - let display_discr_i = format_discriminant_overflow(tcx, variant_i, disr_vals[i]); - let no_disr = v.disr_expr.is_none(); - let mut err = struct_span_err!( - tcx.sess, - sp, - E0081, - "discriminant value `{}` assigned more than once", - discr, - ); - - err.span_label(i_span, format!("first assignment of {display_discr_i}")); - err.span_label(span, format!("second assignment of {display_discr}")); - - if no_disr { - err.span_label( - prev_variant_span, - format!( - "assigned discriminant for `{}` was incremented from this discriminant", - v.ident - ), - ); - } - err.emit(); - } - - disr_vals.push(discr); - prev_variant_span = v.span; - } + detect_discriminant_duplicate(tcx, def.discriminants(tcx).collect(), vs, sp); check_representable(tcx, sp, def_id); check_transparent(tcx, sp, def); } -/// In the case that a discriminant is both a duplicate and an overflowing literal, -/// we insert both the assigned discriminant and the literal it overflowed from into the formatted -/// output. Otherwise we format the discriminant normally. -fn format_discriminant_overflow<'tcx>( +/// Part of enum check. Given the discriminants of an enum, errors if two or more discriminants are equal +fn detect_discriminant_duplicate<'tcx>( tcx: TyCtxt<'tcx>, - variant: &hir::Variant<'_>, - dis: Discr<'tcx>, -) -> String { - if let Some(expr) = &variant.disr_expr { - let body = &tcx.hir().body(expr.body).value; - if let hir::ExprKind::Lit(lit) = &body.kind - && let rustc_ast::LitKind::Int(lit_value, _int_kind) = &lit.node - && dis.val != *lit_value - { - return format!("`{dis}` (overflowed from `{lit_value}`)"); + mut discrs: Vec<(VariantIdx, Discr<'tcx>)>, + vs: &'tcx [hir::Variant<'tcx>], + self_span: Span, +) { + // Helper closure to reduce duplicate code. This gets called everytime we detect a duplicate. + // Here `idx` refers to the order of which the discriminant appears, and its index in `vs` + let report = |dis: Discr<'tcx>, idx: usize, err: &mut Diagnostic| { + let var = &vs[idx]; // HIR for the duplicate discriminant + let (span, display_discr) = match var.disr_expr { + Some(ref expr) => { + // In the case the discriminant is both a duplicate and overflowed, let the user know + if let hir::ExprKind::Lit(lit) = &tcx.hir().body(expr.body).value.kind + && let rustc_ast::LitKind::Int(lit_value, _int_kind) = &lit.node + && *lit_value != dis.val + { + (tcx.hir().span(expr.hir_id), format!("`{dis}` (overflowed from `{lit_value}`)")) + // Otherwise, format the value as-is + } else { + (tcx.hir().span(expr.hir_id), format!("`{dis}`")) + } + } + None => { + // At this point we know this discriminant is a duplicate, and was not explicitly + // assigned by the user. Here we iterate backwards to fetch the HIR for the last + // explicitly assigned discriminant, and letting the user know that this was the + // increment startpoint, and how many steps from there leading to the duplicate + if let Some((n, hir::Variant { span, ident, .. })) = + vs[..idx].iter().rev().enumerate().find(|v| v.1.disr_expr.is_some()) + { + let ve_ident = var.ident; + let n = n + 1; + let sp = if n > 1 { "variants" } else { "variant" }; + + err.span_label( + *span, + format!("discriminant for `{ve_ident}` incremented from this startpoint (`{ident}` + {n} {sp} later => `{ve_ident}` = {dis})"), + ); + } + + (vs[idx].span, format!("`{dis}`")) + } + }; + + err.span_label(span, format!("{display_discr} assigned here")); + }; + + // Here we loop through the discriminants, comparing each discriminant to another. + // When a duplicate is detected, we instantiate an error and point to both + // initial and duplicate value. The duplicate discriminant is then discarded by swapping + // it with the last element and decrementing the `vec.len` (which is why we have to evaluate + // `discrs.len()` anew every iteration, and why this could be tricky to do in a functional + // style as we are mutating `discrs` on the fly). + let mut i = 0; + while i < discrs.len() { + let hir_var_i_idx = discrs[i].0.index(); + let mut error: Option<DiagnosticBuilder<'_, _>> = None; + + let mut o = i + 1; + while o < discrs.len() { + let hir_var_o_idx = discrs[o].0.index(); + + if discrs[i].1.val == discrs[o].1.val { + let err = error.get_or_insert_with(|| { + let mut ret = struct_span_err!( + tcx.sess, + self_span, + E0081, + "discriminant value `{}` assigned more than once", + discrs[i].1, + ); + + report(discrs[i].1, hir_var_i_idx, &mut ret); + + ret + }); + + report(discrs[o].1, hir_var_o_idx, err); + + // Safe to unwrap here, as we wouldn't reach this point if `discrs` was empty + discrs[o] = *discrs.last().unwrap(); + discrs.pop(); + } else { + o += 1; + } } - } - format!("`{dis}`") + if let Some(mut e) = error { + e.emit(); + } + + i += 1; + } } pub(super) fn check_type_params_are_used<'tcx>( |