From 72fe79244d39c356e6fa1da4dfa58354983f98f7 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Mon, 29 Aug 2022 04:19:14 +0000 Subject: [PATCH] Simplify get_trait_ref a bit --- compiler/rustc_codegen_ssa/src/meth.rs | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/compiler/rustc_codegen_ssa/src/meth.rs b/compiler/rustc_codegen_ssa/src/meth.rs index 27d791d90a51a..f8e982b775189 100644 --- a/compiler/rustc_codegen_ssa/src/meth.rs +++ b/compiler/rustc_codegen_ssa/src/meth.rs @@ -1,6 +1,6 @@ use crate::traits::*; -use rustc_middle::ty::{self, subst::GenericArgKind, ExistentialPredicate, Ty, TyCtxt}; +use rustc_middle::ty::{self, subst::GenericArgKind, Ty}; use rustc_session::config::Lto; use rustc_symbol_mangling::typeid_for_trait_ref; use rustc_target::abi::call::FnAbi; @@ -29,7 +29,7 @@ impl<'a, 'tcx> VirtualIndex { && bx.cx().sess().lto() == Lto::Fat { let typeid = - bx.typeid_metadata(typeid_for_trait_ref(bx.tcx(), get_trait_ref(bx.tcx(), ty))); + bx.typeid_metadata(typeid_for_trait_ref(bx.tcx(), expect_dyn_trait_in_self(ty))); let vtable_byte_offset = self.0 * bx.data_layout().pointer_size.bytes(); let type_checked_load = bx.type_checked_load(llvtable, vtable_byte_offset, typeid); let func = bx.extract_value(type_checked_load, 0); @@ -64,17 +64,13 @@ impl<'a, 'tcx> VirtualIndex { } } -fn get_trait_ref<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ty::PolyExistentialTraitRef<'tcx> { +/// This takes a valid `self` receiver type and extracts the principal trait +/// ref of the type. +fn expect_dyn_trait_in_self<'tcx>(ty: Ty<'tcx>) -> ty::PolyExistentialTraitRef<'tcx> { for arg in ty.peel_refs().walk() { if let GenericArgKind::Type(ty) = arg.unpack() { - if let ty::Dynamic(trait_refs, _) = ty.kind() { - return trait_refs[0].map_bound(|trait_ref| match trait_ref { - ExistentialPredicate::Trait(tr) => tr, - ExistentialPredicate::Projection(proj) => proj.trait_ref(tcx), - ExistentialPredicate::AutoTrait(_) => { - bug!("auto traits don't have functions") - } - }); + if let ty::Dynamic(data, _) = ty.kind() { + return data.principal().expect("expected principal trait object"); } } }