//! Definition of [`CValue`] and [`CPlace`] use crate::prelude::*; use cranelift_codegen::ir::immediates::Offset32; fn codegen_field<'tcx>( fx: &mut FunctionCx<'_, '_, 'tcx>, base: Pointer, extra: Option, layout: TyAndLayout<'tcx>, field: mir::Field, ) -> (Pointer, TyAndLayout<'tcx>) { let field_offset = layout.fields.offset(field.index()); let field_layout = layout.field(&*fx, field.index()); let simple = |fx: &mut FunctionCx<'_, '_, '_>| { (base.offset_i64(fx, i64::try_from(field_offset.bytes()).unwrap()), field_layout) }; if let Some(extra) = extra { if !field_layout.is_unsized() { return simple(fx); } match field_layout.ty.kind() { ty::Slice(..) | ty::Str | ty::Foreign(..) => simple(fx), ty::Adt(def, _) if def.repr.packed() => { assert_eq!(layout.align.abi.bytes(), 1); simple(fx) } _ => { // We have to align the offset for DST's let unaligned_offset = field_offset.bytes(); let (_, unsized_align) = crate::unsize::size_and_align_of_dst(fx, field_layout, extra); let one = fx.bcx.ins().iconst(pointer_ty(fx.tcx), 1); let align_sub_1 = fx.bcx.ins().isub(unsized_align, one); let and_lhs = fx.bcx.ins().iadd_imm(align_sub_1, unaligned_offset as i64); let zero = fx.bcx.ins().iconst(pointer_ty(fx.tcx), 0); let and_rhs = fx.bcx.ins().isub(zero, unsized_align); let offset = fx.bcx.ins().band(and_lhs, and_rhs); (base.offset_value(fx, offset), field_layout) } } } else { simple(fx) } } fn scalar_pair_calculate_b_offset( tcx: TyCtxt<'_>, a_scalar: &Scalar, b_scalar: &Scalar, ) -> Offset32 { let b_offset = a_scalar.value.size(&tcx).align_to(b_scalar.value.align(&tcx).abi); Offset32::new(b_offset.bytes().try_into().unwrap()) } /// A read-only value #[derive(Debug, Copy, Clone)] pub(crate) struct CValue<'tcx>(CValueInner, TyAndLayout<'tcx>); #[derive(Debug, Copy, Clone)] enum CValueInner { ByRef(Pointer, Option), ByVal(Value), ByValPair(Value, Value), } impl<'tcx> CValue<'tcx> { pub(crate) fn by_ref(ptr: Pointer, layout: TyAndLayout<'tcx>) -> CValue<'tcx> { CValue(CValueInner::ByRef(ptr, None), layout) } pub(crate) fn by_ref_unsized( ptr: Pointer, meta: Value, layout: TyAndLayout<'tcx>, ) -> CValue<'tcx> { CValue(CValueInner::ByRef(ptr, Some(meta)), layout) } pub(crate) fn by_val(value: Value, layout: TyAndLayout<'tcx>) -> CValue<'tcx> { CValue(CValueInner::ByVal(value), layout) } pub(crate) fn by_val_pair( value: Value, extra: Value, layout: TyAndLayout<'tcx>, ) -> CValue<'tcx> { CValue(CValueInner::ByValPair(value, extra), layout) } pub(crate) fn layout(&self) -> TyAndLayout<'tcx> { self.1 } // FIXME remove pub(crate) fn force_stack(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> (Pointer, Option) { let layout = self.1; match self.0 { CValueInner::ByRef(ptr, meta) => (ptr, meta), CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => { let cplace = CPlace::new_stack_slot(fx, layout); cplace.write_cvalue(fx, self); (cplace.to_ptr(), None) } } } pub(crate) fn try_to_ptr(self) -> Option<(Pointer, Option)> { match self.0 { CValueInner::ByRef(ptr, meta) => Some((ptr, meta)), CValueInner::ByVal(_) | CValueInner::ByValPair(_, _) => None, } } /// Load a value with layout.abi of scalar pub(crate) fn load_scalar(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> Value { let layout = self.1; match self.0 { CValueInner::ByRef(ptr, None) => { let clif_ty = match layout.abi { Abi::Scalar(ref scalar) => scalar_to_clif_type(fx.tcx, scalar.clone()), Abi::Vector { ref element, count } => { scalar_to_clif_type(fx.tcx, element.clone()) .by(u16::try_from(count).unwrap()) .unwrap() } _ => unreachable!("{:?}", layout.ty), }; let mut flags = MemFlags::new(); flags.set_notrap(); ptr.load(fx, clif_ty, flags) } CValueInner::ByVal(value) => value, CValueInner::ByRef(_, Some(_)) => bug!("load_scalar for unsized value not allowed"), CValueInner::ByValPair(_, _) => bug!("Please use load_scalar_pair for ByValPair"), } } /// Load a value pair with layout.abi of scalar pair pub(crate) fn load_scalar_pair(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> (Value, Value) { let layout = self.1; match self.0 { CValueInner::ByRef(ptr, None) => { let (a_scalar, b_scalar) = match &layout.abi { Abi::ScalarPair(a, b) => (a, b), _ => unreachable!("load_scalar_pair({:?})", self), }; let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar); let clif_ty1 = scalar_to_clif_type(fx.tcx, a_scalar.clone()); let clif_ty2 = scalar_to_clif_type(fx.tcx, b_scalar.clone()); let mut flags = MemFlags::new(); flags.set_notrap(); let val1 = ptr.load(fx, clif_ty1, flags); let val2 = ptr.offset(fx, b_offset).load(fx, clif_ty2, flags); (val1, val2) } CValueInner::ByRef(_, Some(_)) => { bug!("load_scalar_pair for unsized value not allowed") } CValueInner::ByVal(_) => bug!("Please use load_scalar for ByVal"), CValueInner::ByValPair(val1, val2) => (val1, val2), } } pub(crate) fn value_field( self, fx: &mut FunctionCx<'_, '_, 'tcx>, field: mir::Field, ) -> CValue<'tcx> { let layout = self.1; match self.0 { CValueInner::ByVal(val) => match layout.abi { Abi::Vector { element: _, count } => { let count = u8::try_from(count).expect("SIMD type with more than 255 lanes???"); let field = u8::try_from(field.index()).unwrap(); assert!(field < count); let lane = fx.bcx.ins().extractlane(val, field); let field_layout = layout.field(&*fx, usize::from(field)); CValue::by_val(lane, field_layout) } _ => unreachable!("value_field for ByVal with abi {:?}", layout.abi), }, CValueInner::ByValPair(val1, val2) => match layout.abi { Abi::ScalarPair(_, _) => { let val = match field.as_u32() { 0 => val1, 1 => val2, _ => bug!("field should be 0 or 1"), }; let field_layout = layout.field(&*fx, usize::from(field)); CValue::by_val(val, field_layout) } _ => unreachable!("value_field for ByValPair with abi {:?}", layout.abi), }, CValueInner::ByRef(ptr, None) => { let (field_ptr, field_layout) = codegen_field(fx, ptr, None, layout, field); CValue::by_ref(field_ptr, field_layout) } CValueInner::ByRef(_, Some(_)) => todo!(), } } pub(crate) fn unsize_value(self, fx: &mut FunctionCx<'_, '_, 'tcx>, dest: CPlace<'tcx>) { crate::unsize::coerce_unsized_into(fx, self, dest); } /// If `ty` is signed, `const_val` must already be sign extended. pub(crate) fn const_val( fx: &mut FunctionCx<'_, '_, 'tcx>, layout: TyAndLayout<'tcx>, const_val: ty::ScalarInt, ) -> CValue<'tcx> { assert_eq!(const_val.size(), layout.size, "{:#?}: {:?}", const_val, layout); use cranelift_codegen::ir::immediates::{Ieee32, Ieee64}; let clif_ty = fx.clif_type(layout.ty).unwrap(); if let ty::Bool = layout.ty.kind() { assert!( const_val == ty::ScalarInt::FALSE || const_val == ty::ScalarInt::TRUE, "Invalid bool 0x{:032X}", const_val ); } let val = match layout.ty.kind() { ty::Uint(UintTy::U128) | ty::Int(IntTy::I128) => { let const_val = const_val.to_bits(layout.size).unwrap(); let lsb = fx.bcx.ins().iconst(types::I64, const_val as u64 as i64); let msb = fx.bcx.ins().iconst(types::I64, (const_val >> 64) as u64 as i64); fx.bcx.ins().iconcat(lsb, msb) } ty::Bool | ty::Char | ty::Uint(_) | ty::Int(_) | ty::Ref(..) | ty::RawPtr(..) => { fx.bcx.ins().iconst(clif_ty, const_val.to_bits(layout.size).unwrap() as i64) } ty::Float(FloatTy::F32) => { fx.bcx.ins().f32const(Ieee32::with_bits(u32::try_from(const_val).unwrap())) } ty::Float(FloatTy::F64) => { fx.bcx.ins().f64const(Ieee64::with_bits(u64::try_from(const_val).unwrap())) } _ => panic!( "CValue::const_val for non bool/char/float/integer/pointer type {:?} is not allowed", layout.ty ), }; CValue::by_val(val, layout) } pub(crate) fn cast_pointer_to(self, layout: TyAndLayout<'tcx>) -> Self { assert!(matches!(self.layout().ty.kind(), ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..))); assert!(matches!(layout.ty.kind(), ty::Ref(..) | ty::RawPtr(..) | ty::FnPtr(..))); assert_eq!(self.layout().abi, layout.abi); CValue(self.0, layout) } } /// A place where you can write a value to or read a value from #[derive(Debug, Copy, Clone)] pub(crate) struct CPlace<'tcx> { inner: CPlaceInner, layout: TyAndLayout<'tcx>, } #[derive(Debug, Copy, Clone)] pub(crate) enum CPlaceInner { Var(Local, Variable), VarPair(Local, Variable, Variable), VarLane(Local, Variable, u8), Addr(Pointer, Option), } impl<'tcx> CPlace<'tcx> { pub(crate) fn layout(&self) -> TyAndLayout<'tcx> { self.layout } pub(crate) fn inner(&self) -> &CPlaceInner { &self.inner } pub(crate) fn no_place(layout: TyAndLayout<'tcx>) -> CPlace<'tcx> { CPlace { inner: CPlaceInner::Addr(Pointer::dangling(layout.align.pref), None), layout } } pub(crate) fn new_stack_slot( fx: &mut FunctionCx<'_, '_, 'tcx>, layout: TyAndLayout<'tcx>, ) -> CPlace<'tcx> { assert!(!layout.is_unsized()); if layout.size.bytes() == 0 { return CPlace::no_place(layout); } let stack_slot = fx.bcx.create_stack_slot(StackSlotData { kind: StackSlotKind::ExplicitSlot, // FIXME Don't force the size to a multiple of 16 bytes once Cranelift gets a way to // specify stack slot alignment. size: (u32::try_from(layout.size.bytes()).unwrap() + 15) / 16 * 16, offset: None, }); CPlace { inner: CPlaceInner::Addr(Pointer::stack_slot(stack_slot), None), layout } } pub(crate) fn new_var( fx: &mut FunctionCx<'_, '_, 'tcx>, local: Local, layout: TyAndLayout<'tcx>, ) -> CPlace<'tcx> { let var = Variable::with_u32(fx.next_ssa_var); fx.next_ssa_var += 1; fx.bcx.declare_var(var, fx.clif_type(layout.ty).unwrap()); CPlace { inner: CPlaceInner::Var(local, var), layout } } pub(crate) fn new_var_pair( fx: &mut FunctionCx<'_, '_, 'tcx>, local: Local, layout: TyAndLayout<'tcx>, ) -> CPlace<'tcx> { let var1 = Variable::with_u32(fx.next_ssa_var); fx.next_ssa_var += 1; let var2 = Variable::with_u32(fx.next_ssa_var); fx.next_ssa_var += 1; let (ty1, ty2) = fx.clif_pair_type(layout.ty).unwrap(); fx.bcx.declare_var(var1, ty1); fx.bcx.declare_var(var2, ty2); CPlace { inner: CPlaceInner::VarPair(local, var1, var2), layout } } pub(crate) fn for_ptr(ptr: Pointer, layout: TyAndLayout<'tcx>) -> CPlace<'tcx> { CPlace { inner: CPlaceInner::Addr(ptr, None), layout } } pub(crate) fn for_ptr_with_extra( ptr: Pointer, extra: Value, layout: TyAndLayout<'tcx>, ) -> CPlace<'tcx> { CPlace { inner: CPlaceInner::Addr(ptr, Some(extra)), layout } } pub(crate) fn to_cvalue(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> CValue<'tcx> { let layout = self.layout(); match self.inner { CPlaceInner::Var(_local, var) => { let val = fx.bcx.use_var(var); //fx.bcx.set_val_label(val, cranelift_codegen::ir::ValueLabel::new(var.index())); CValue::by_val(val, layout) } CPlaceInner::VarPair(_local, var1, var2) => { let val1 = fx.bcx.use_var(var1); //fx.bcx.set_val_label(val1, cranelift_codegen::ir::ValueLabel::new(var1.index())); let val2 = fx.bcx.use_var(var2); //fx.bcx.set_val_label(val2, cranelift_codegen::ir::ValueLabel::new(var2.index())); CValue::by_val_pair(val1, val2, layout) } CPlaceInner::VarLane(_local, var, lane) => { let val = fx.bcx.use_var(var); //fx.bcx.set_val_label(val, cranelift_codegen::ir::ValueLabel::new(var.index())); let val = fx.bcx.ins().extractlane(val, lane); CValue::by_val(val, layout) } CPlaceInner::Addr(ptr, extra) => { if let Some(extra) = extra { CValue::by_ref_unsized(ptr, extra, layout) } else { CValue::by_ref(ptr, layout) } } } } pub(crate) fn to_ptr(self) -> Pointer { match self.to_ptr_maybe_unsized() { (ptr, None) => ptr, (_, Some(_)) => bug!("Expected sized cplace, found {:?}", self), } } pub(crate) fn to_ptr_maybe_unsized(self) -> (Pointer, Option) { match self.inner { CPlaceInner::Addr(ptr, extra) => (ptr, extra), CPlaceInner::Var(_, _) | CPlaceInner::VarPair(_, _, _) | CPlaceInner::VarLane(_, _, _) => bug!("Expected CPlace::Addr, found {:?}", self), } } pub(crate) fn write_cvalue(self, fx: &mut FunctionCx<'_, '_, 'tcx>, from: CValue<'tcx>) { assert_assignable(fx, from.layout().ty, self.layout().ty); self.write_cvalue_maybe_transmute(fx, from, "write_cvalue"); } pub(crate) fn write_cvalue_transmute( self, fx: &mut FunctionCx<'_, '_, 'tcx>, from: CValue<'tcx>, ) { self.write_cvalue_maybe_transmute(fx, from, "write_cvalue_transmute"); } fn write_cvalue_maybe_transmute( self, fx: &mut FunctionCx<'_, '_, 'tcx>, from: CValue<'tcx>, method: &'static str, ) { fn transmute_value<'tcx>( fx: &mut FunctionCx<'_, '_, 'tcx>, var: Variable, data: Value, dst_ty: Type, ) { let src_ty = fx.bcx.func.dfg.value_type(data); assert_eq!( src_ty.bytes(), dst_ty.bytes(), "write_cvalue_transmute: {:?} -> {:?}", src_ty, dst_ty, ); let data = match (src_ty, dst_ty) { (_, _) if src_ty == dst_ty => data, // This is a `write_cvalue_transmute`. (types::I32, types::F32) | (types::F32, types::I32) | (types::I64, types::F64) | (types::F64, types::I64) => fx.bcx.ins().bitcast(dst_ty, data), _ if src_ty.is_vector() && dst_ty.is_vector() => { fx.bcx.ins().raw_bitcast(dst_ty, data) } _ if src_ty.is_vector() || dst_ty.is_vector() => { // FIXME do something more efficient for transmutes between vectors and integers. let stack_slot = fx.bcx.create_stack_slot(StackSlotData { kind: StackSlotKind::ExplicitSlot, // FIXME Don't force the size to a multiple of 16 bytes once Cranelift gets a way to // specify stack slot alignment. size: (src_ty.bytes() + 15) / 16 * 16, offset: None, }); let ptr = Pointer::stack_slot(stack_slot); ptr.store(fx, data, MemFlags::trusted()); ptr.load(fx, dst_ty, MemFlags::trusted()) } // `CValue`s should never contain SSA-only types, so if you ended // up here having seen an error like `B1 -> I8`, then before // calling `write_cvalue` you need to add a `bint` instruction. _ => unreachable!("write_cvalue_transmute: {:?} -> {:?}", src_ty, dst_ty), }; //fx.bcx.set_val_label(data, cranelift_codegen::ir::ValueLabel::new(var.index())); fx.bcx.def_var(var, data); } assert_eq!(self.layout().size, from.layout().size); if fx.clif_comments.enabled() { use cranelift_codegen::cursor::{Cursor, CursorPosition}; let cur_block = match fx.bcx.cursor().position() { CursorPosition::After(block) => block, _ => unreachable!(), }; fx.add_comment( fx.bcx.func.layout.last_inst(cur_block).unwrap(), format!( "{}: {:?}: {:?} <- {:?}: {:?}", method, self.inner(), self.layout().ty, from.0, from.layout().ty ), ); } let dst_layout = self.layout(); let to_ptr = match self.inner { CPlaceInner::Var(_local, var) => { let data = CValue(from.0, dst_layout).load_scalar(fx); let dst_ty = fx.clif_type(self.layout().ty).unwrap(); transmute_value(fx, var, data, dst_ty); return; } CPlaceInner::VarPair(_local, var1, var2) => { let (data1, data2) = CValue(from.0, dst_layout).load_scalar_pair(fx); let (dst_ty1, dst_ty2) = fx.clif_pair_type(self.layout().ty).unwrap(); transmute_value(fx, var1, data1, dst_ty1); transmute_value(fx, var2, data2, dst_ty2); return; } CPlaceInner::VarLane(_local, var, lane) => { let data = from.load_scalar(fx); // First get the old vector let vector = fx.bcx.use_var(var); //fx.bcx.set_val_label(vector, cranelift_codegen::ir::ValueLabel::new(var.index())); // Next insert the written lane into the vector let vector = fx.bcx.ins().insertlane(vector, data, lane); // Finally write the new vector //fx.bcx.set_val_label(vector, cranelift_codegen::ir::ValueLabel::new(var.index())); fx.bcx.def_var(var, vector); return; } CPlaceInner::Addr(ptr, None) => { if dst_layout.size == Size::ZERO || dst_layout.abi == Abi::Uninhabited { return; } ptr } CPlaceInner::Addr(_, Some(_)) => bug!("Can't write value to unsized place {:?}", self), }; let mut flags = MemFlags::new(); flags.set_notrap(); match from.layout().abi { // FIXME make Abi::Vector work too Abi::Scalar(_) => { let val = from.load_scalar(fx); to_ptr.store(fx, val, flags); return; } Abi::ScalarPair(ref a_scalar, ref b_scalar) => { let (value, extra) = from.load_scalar_pair(fx); let b_offset = scalar_pair_calculate_b_offset(fx.tcx, a_scalar, b_scalar); to_ptr.store(fx, value, flags); to_ptr.offset(fx, b_offset).store(fx, extra, flags); return; } _ => {} } match from.0 { CValueInner::ByVal(val) => { to_ptr.store(fx, val, flags); } CValueInner::ByValPair(_, _) => { bug!("Non ScalarPair abi {:?} for ByValPair CValue", dst_layout.abi); } CValueInner::ByRef(from_ptr, None) => { let from_addr = from_ptr.get_addr(fx); let to_addr = to_ptr.get_addr(fx); let src_layout = from.1; let size = dst_layout.size.bytes(); let src_align = src_layout.align.abi.bytes() as u8; let dst_align = dst_layout.align.abi.bytes() as u8; fx.bcx.emit_small_memory_copy( fx.module.target_config(), to_addr, from_addr, size, dst_align, src_align, true, MemFlags::trusted(), ); } CValueInner::ByRef(_, Some(_)) => todo!(), } } pub(crate) fn place_field( self, fx: &mut FunctionCx<'_, '_, 'tcx>, field: mir::Field, ) -> CPlace<'tcx> { let layout = self.layout(); match self.inner { CPlaceInner::Var(local, var) => { if let Abi::Vector { .. } = layout.abi { return CPlace { inner: CPlaceInner::VarLane(local, var, field.as_u32().try_into().unwrap()), layout: layout.field(fx, field.as_u32().try_into().unwrap()), }; } } CPlaceInner::VarPair(local, var1, var2) => { let layout = layout.field(&*fx, field.index()); match field.as_u32() { 0 => return CPlace { inner: CPlaceInner::Var(local, var1), layout }, 1 => return CPlace { inner: CPlaceInner::Var(local, var2), layout }, _ => unreachable!("field should be 0 or 1"), } } _ => {} } let (base, extra) = self.to_ptr_maybe_unsized(); let (field_ptr, field_layout) = codegen_field(fx, base, extra, layout, field); if field_layout.is_unsized() { CPlace::for_ptr_with_extra(field_ptr, extra.unwrap(), field_layout) } else { CPlace::for_ptr(field_ptr, field_layout) } } pub(crate) fn place_index( self, fx: &mut FunctionCx<'_, '_, 'tcx>, index: Value, ) -> CPlace<'tcx> { let (elem_layout, ptr) = match self.layout().ty.kind() { ty::Array(elem_ty, _) => (fx.layout_of(elem_ty), self.to_ptr()), ty::Slice(elem_ty) => (fx.layout_of(elem_ty), self.to_ptr_maybe_unsized().0), _ => bug!("place_index({:?})", self.layout().ty), }; let offset = fx.bcx.ins().imul_imm(index, elem_layout.size.bytes() as i64); CPlace::for_ptr(ptr.offset_value(fx, offset), elem_layout) } pub(crate) fn place_deref(self, fx: &mut FunctionCx<'_, '_, 'tcx>) -> CPlace<'tcx> { let inner_layout = fx.layout_of(self.layout().ty.builtin_deref(true).unwrap().ty); if has_ptr_meta(fx.tcx, inner_layout.ty) { let (addr, extra) = self.to_cvalue(fx).load_scalar_pair(fx); CPlace::for_ptr_with_extra(Pointer::new(addr), extra, inner_layout) } else { CPlace::for_ptr(Pointer::new(self.to_cvalue(fx).load_scalar(fx)), inner_layout) } } pub(crate) fn place_ref( self, fx: &mut FunctionCx<'_, '_, 'tcx>, layout: TyAndLayout<'tcx>, ) -> CValue<'tcx> { if has_ptr_meta(fx.tcx, self.layout().ty) { let (ptr, extra) = self.to_ptr_maybe_unsized(); CValue::by_val_pair( ptr.get_addr(fx), extra.expect("unsized type without metadata"), layout, ) } else { CValue::by_val(self.to_ptr().get_addr(fx), layout) } } pub(crate) fn downcast_variant( self, fx: &FunctionCx<'_, '_, 'tcx>, variant: VariantIdx, ) -> Self { assert!(!self.layout().is_unsized()); let layout = self.layout().for_variant(fx, variant); CPlace { inner: self.inner, layout } } } #[track_caller] pub(crate) fn assert_assignable<'tcx>( fx: &FunctionCx<'_, '_, 'tcx>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>, ) { match (from_ty.kind(), to_ty.kind()) { (ty::Ref(_, a, _), ty::Ref(_, b, _)) | ( ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }), ty::RawPtr(TypeAndMut { ty: b, mutbl: _ }), ) => { assert_assignable(fx, a, b); } (ty::Ref(_, a, _), ty::RawPtr(TypeAndMut { ty: b, mutbl: _ })) | (ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }), ty::Ref(_, b, _)) => { assert_assignable(fx, a, b); } (ty::FnPtr(_), ty::FnPtr(_)) => { let from_sig = fx.tcx.normalize_erasing_late_bound_regions( ParamEnv::reveal_all(), from_ty.fn_sig(fx.tcx), ); let to_sig = fx .tcx .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), to_ty.fn_sig(fx.tcx)); assert_eq!( from_sig, to_sig, "Can't write fn ptr with incompatible sig {:?} to place with sig {:?}\n\n{:#?}", from_sig, to_sig, fx, ); // fn(&T) -> for<'l> fn(&'l T) is allowed } (&ty::Dynamic(from_traits, _), &ty::Dynamic(to_traits, _)) => { for (from, to) in from_traits.iter().zip(to_traits) { let from = fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), from); let to = fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), to); assert_eq!( from, to, "Can't write trait object of incompatible traits {:?} to place with traits {:?}\n\n{:#?}", from_traits, to_traits, fx, ); } // dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed } (&ty::Adt(adt_def_a, substs_a), &ty::Adt(adt_def_b, substs_b)) if adt_def_a.did == adt_def_b.did => { let mut types_a = substs_a.types(); let mut types_b = substs_b.types(); loop { match (types_a.next(), types_b.next()) { (Some(a), Some(b)) => assert_assignable(fx, a, b), (None, None) => return, (Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty), } } } _ => { assert_eq!( from_ty, to_ty, "Can't write value with incompatible type {:?} to place with type {:?}\n\n{:#?}", from_ty, to_ty, fx, ); } } }