diff options
| -rw-r--r-- | compiler/rustc_middle/src/mir/mod.rs | 47 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/pattern/mod.rs | 93 |
2 files changed, 62 insertions, 78 deletions
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs index 72cd2218e4a..4e7cb6853ea 100644 --- a/compiler/rustc_middle/src/mir/mod.rs +++ b/compiler/rustc_middle/src/mir/mod.rs @@ -3,7 +3,7 @@ //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/mir/index.html use crate::mir::interpret::{ - AllocRange, ConstAllocation, ConstValue, ErrorHandled, GlobalAlloc, LitToConstInput, Scalar, + AllocRange, ConstAllocation, ConstValue, ErrorHandled, GlobalAlloc, Scalar, }; use crate::mir::visit::MirVisitable; use crate::ty::codec::{TyDecoder, TyEncoder}; @@ -2461,51 +2461,6 @@ impl<'tcx> ConstantKind<'tcx> { Self::Val(val, ty) } - #[instrument(skip(tcx), level = "debug", ret)] - pub fn from_inline_const(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self { - let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); - let body_id = match tcx.hir().get(hir_id) { - hir::Node::AnonConst(ac) => ac.body, - _ => span_bug!( - tcx.def_span(def_id.to_def_id()), - "from_inline_const can only process anonymous constants" - ), - }; - let expr = &tcx.hir().body(body_id).value; - let ty = tcx.typeck(def_id).node_type(hir_id); - - let lit_input = match expr.kind { - hir::ExprKind::Lit(ref lit) => Some(LitToConstInput { lit: &lit.node, ty, neg: false }), - hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => match expr.kind { - hir::ExprKind::Lit(ref lit) => { - Some(LitToConstInput { lit: &lit.node, ty, neg: true }) - } - _ => None, - }, - _ => None, - }; - if let Some(lit_input) = lit_input { - // If an error occurred, ignore that it's a literal and leave reporting the error up to - // mir. - match tcx.at(expr.span).lit_to_const(lit_input) { - Ok(c) => return Self::Ty(c), - Err(_) => {} - } - } - - let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id()); - let parent_substs = - tcx.erase_regions(InternalSubsts::identity_for_item(tcx, typeck_root_def_id)); - let substs = - ty::InlineConstSubsts::new(tcx, ty::InlineConstSubstsParts { parent_substs, ty }) - .substs; - - let uneval = UnevaluatedConst { def: def_id.to_def_id(), substs, promoted: None }; - debug_assert!(!uneval.has_free_regions()); - - Self::Unevaluated(uneval, ty) - } - /// Literals are converted to `ConstantKindVal`, const generic parameters are eagerly /// converted to a constant, everything else becomes `Unevaluated`. #[instrument(skip(tcx), level = "debug", ret)] diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs index 21451224eb4..1bbe7b45c1e 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs @@ -25,7 +25,8 @@ use rustc_middle::mir::{BorrowKind, Mutability}; use rustc_middle::thir::{Ascription, BindingMode, FieldPat, LocalVarId, Pat, PatKind, PatRange}; use rustc_middle::ty::subst::{GenericArg, SubstsRef}; use rustc_middle::ty::CanonicalUserTypeAnnotation; -use rustc_middle::ty::{self, AdtDef, ConstKind, Region, Ty, TyCtxt, UserType}; +use rustc_middle::ty::TypeVisitableExt; +use rustc_middle::ty::{self, AdtDef, Region, Ty, TyCtxt, UserType}; use rustc_span::{Span, Symbol}; use rustc_target::abi::FieldIdx; @@ -585,43 +586,71 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> { id: hir::HirId, span: Span, ) -> PatKind<'tcx> { - let value = mir::ConstantKind::from_inline_const(self.tcx, anon_const.def_id); - let value = match value { - mir::ConstantKind::Ty(_) => value, - // Evaluate early like we do in `lower_path`. - mir::ConstantKind::Unevaluated(ct, ty) => { - let ct = ty::UnevaluatedConst { def: ct.def, substs: ct.substs }; - if let Ok(Some(valtree)) = - self.tcx.const_eval_resolve_for_typeck(self.param_env, ct, Some(span)) - { - mir::ConstantKind::Ty(self.tcx.mk_const(valtree, ty)) - } else { - value.eval(self.tcx, self.param_env) - } - } - mir::ConstantKind::Val(_, _) => unreachable!(), + let tcx = self.tcx; + let def_id = anon_const.def_id; + let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + let body_id = match tcx.hir().get(hir_id) { + hir::Node::AnonConst(ac) => ac.body, + _ => span_bug!( + tcx.def_span(def_id.to_def_id()), + "from_inline_const can only process anonymous constants" + ), }; - - match value { - mir::ConstantKind::Ty(c) => match c.kind() { - ConstKind::Param(_) => { - self.tcx.sess.emit_err(ConstParamInPattern { span }); - return PatKind::Wild; - } - ConstKind::Error(_) => { - return PatKind::Wild; + let expr = &tcx.hir().body(body_id).value; + let ty = tcx.typeck(def_id).node_type(hir_id); + + // Special case inline consts that are just literals. This is solely + // a performance optimization, as we could also just go through the regular + // const eval path below. + // FIXME: investigate the performance impact of removing this. + let lit_input = match expr.kind { + hir::ExprKind::Lit(ref lit) => Some(LitToConstInput { lit: &lit.node, ty, neg: false }), + hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => match expr.kind { + hir::ExprKind::Lit(ref lit) => { + Some(LitToConstInput { lit: &lit.node, ty, neg: true }) } - _ => {} + _ => None, }, - mir::ConstantKind::Val(_, _) => {} - mir::ConstantKind::Unevaluated(..) => { - // If we land here it means the const can't be evaluated because it's `TooGeneric`. - self.tcx.sess.emit_err(ConstPatternDependsOnGenericParameter { span }); - return PatKind::Wild; + _ => None, + }; + if let Some(lit_input) = lit_input { + match tcx.at(expr.span).lit_to_const(lit_input) { + Ok(c) => return self.const_to_pat(ConstantKind::Ty(c), id, span, None).kind, + // If an error occurred, ignore that it's a literal + // and leave reporting the error up to const eval of + // the unevaluated constant below. + Err(_) => {} } } - self.const_to_pat(value, id, span, None).kind + let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id()); + let parent_substs = + tcx.erase_regions(ty::InternalSubsts::identity_for_item(tcx, typeck_root_def_id)); + let substs = + ty::InlineConstSubsts::new(tcx, ty::InlineConstSubstsParts { parent_substs, ty }) + .substs; + + let uneval = mir::UnevaluatedConst { def: def_id.to_def_id(), substs, promoted: None }; + debug_assert!(!substs.has_free_regions()); + + let ct = ty::UnevaluatedConst { def: def_id.to_def_id(), substs: substs }; + // First try using a valtree in order to destructure the constant into a pattern. + if let Ok(Some(valtree)) = + self.tcx.const_eval_resolve_for_typeck(self.param_env, ct, Some(span)) + { + self.const_to_pat(ConstantKind::Ty(self.tcx.mk_const(valtree, ty)), id, span, None).kind + } else { + // If that fails, convert it to an opaque constant pattern. + match tcx.const_eval_resolve(self.param_env, uneval, None) { + Ok(val) => self.const_to_pat(mir::ConstantKind::Val(val, ty), id, span, None).kind, + Err(ErrorHandled::TooGeneric) => { + // If we land here it means the const can't be evaluated because it's `TooGeneric`. + self.tcx.sess.emit_err(ConstPatternDependsOnGenericParameter { span }); + PatKind::Wild + } + Err(ErrorHandled::Reported(_)) => PatKind::Wild, + } + } } /// Converts literals, paths and negation of literals to patterns. |