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Auto merge of #122500 - petrochenkov:deleg, r=fmease

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delegation: Support renaming, and async, const, extern "ABI" and C-variadic functions

Also allow delegating to functions with opaque types (`impl Trait`).
The delegation item will refer to the original opaque type from the callee, fresh opaque type won't be created, which seems like a reasonable behavior.
(Such delegation items will cause query cycles when used in trait impls, but it can be fixed later.)

Part of https://github.com/rust-lang/rust/issues/118212.
This commit is contained in:
bors 2024-04-24 11:57:35 +00:00
commit 5557f8c9d0
17 changed files with 282 additions and 160 deletions
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117
compiler/rustc_ast_lowering/src/delegation.rs
View file

@ -49,7 +49,7 @@ use rustc_errors::ErrorGuaranteed;
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_middle::span_bug;
use rustc_middle::ty::ResolverAstLowering;
use rustc_middle::ty::{Asyncness, ResolverAstLowering};
use rustc_span::{symbol::Ident, Span};
use rustc_target::spec::abi;
use std::iter;
@ -67,7 +67,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
return false;
};
if let Some(local_sig_id) = sig_id.as_local() {
self.resolver.has_self.contains(&local_sig_id)
self.resolver.delegation_fn_sigs[&local_sig_id].has_self
} else {
match self.tcx.def_kind(sig_id) {
DefKind::Fn => false,
@ -82,13 +82,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
delegation: &Delegation,
item_id: NodeId,
) -> DelegationResults<'hir> {
let span = delegation.path.segments.last().unwrap().ident.span;
let span = self.lower_span(delegation.path.segments.last().unwrap().ident.span);
let sig_id = self.get_delegation_sig_id(item_id, delegation.id, span);
match sig_id {
Ok(sig_id) => {
let decl = self.lower_delegation_decl(sig_id, span);
let sig = self.lower_delegation_sig(span, decl);
let body_id = self.lower_delegation_body(sig.decl, delegation);
let (param_count, c_variadic) = self.param_count(sig_id);
let decl = self.lower_delegation_decl(sig_id, param_count, c_variadic, span);
let sig = self.lower_delegation_sig(sig_id, decl, span);
let body_id = self.lower_delegation_body(delegation, param_count, span);
let generics = self.lower_delegation_generics(span);
DelegationResults { body_id, sig, generics }
@ -123,34 +124,47 @@ impl<'hir> LoweringContext<'_, 'hir> {
})
}
// Function parameter count, including C variadic `...` if present.
fn param_count(&self, sig_id: DefId) -> (usize, bool /*c_variadic*/) {
if let Some(local_sig_id) = sig_id.as_local() {
// Map may be filled incorrectly due to recursive delegation.
// Error will be emmited later during HIR ty lowering.
match self.resolver.delegation_fn_sigs.get(&local_sig_id) {
Some(sig) => (sig.param_count, sig.c_variadic),
None => (0, false),
}
} else {
let sig = self.tcx.fn_sig(sig_id).skip_binder().skip_binder();
(sig.inputs().len() + usize::from(sig.c_variadic), sig.c_variadic)
}
}
fn lower_delegation_decl(
&mut self,
sig_id: DefId,
param_span: Span,
param_count: usize,
c_variadic: bool,
span: Span,
) -> &'hir hir::FnDecl<'hir> {
let args_count = if let Some(local_sig_id) = sig_id.as_local() {
// Map may be filled incorrectly due to recursive delegation.
// Error will be emitted later during HIR ty lowering.
self.resolver.fn_parameter_counts.get(&local_sig_id).cloned().unwrap_or_default()
} else {
self.tcx.fn_arg_names(sig_id).len()
};
let inputs = self.arena.alloc_from_iter((0..args_count).map(|arg| hir::Ty {
// The last parameter in C variadic functions is skipped in the signature,
// like during regular lowering.
let decl_param_count = param_count - c_variadic as usize;
let inputs = self.arena.alloc_from_iter((0..decl_param_count).map(|arg| hir::Ty {
hir_id: self.next_id(),
kind: hir::TyKind::InferDelegation(sig_id, hir::InferDelegationKind::Input(arg)),
span: self.lower_span(param_span),
span,
}));
let output = self.arena.alloc(hir::Ty {
hir_id: self.next_id(),
kind: hir::TyKind::InferDelegation(sig_id, hir::InferDelegationKind::Output),
span: self.lower_span(param_span),
span,
});
self.arena.alloc(hir::FnDecl {
inputs,
output: hir::FnRetTy::Return(output),
c_variadic: false,
c_variadic,
lifetime_elision_allowed: true,
implicit_self: hir::ImplicitSelfKind::None,
})
@ -158,35 +172,45 @@ impl<'hir> LoweringContext<'_, 'hir> {
fn lower_delegation_sig(
&mut self,
span: Span,
sig_id: DefId,
decl: &'hir hir::FnDecl<'hir>,
span: Span,
) -> hir::FnSig<'hir> {
hir::FnSig {
decl,
header: hir::FnHeader {
unsafety: hir::Unsafety::Normal,
constness: hir::Constness::NotConst,
asyncness: hir::IsAsync::NotAsync,
abi: abi::Abi::Rust,
},
span: self.lower_span(span),
}
let header = if let Some(local_sig_id) = sig_id.as_local() {
match self.resolver.delegation_fn_sigs.get(&local_sig_id) {
Some(sig) => self.lower_fn_header(sig.header),
None => self.generate_header_error(),
}
} else {
let sig = self.tcx.fn_sig(sig_id).skip_binder().skip_binder();
let asyncness = match self.tcx.asyncness(sig_id) {
Asyncness::Yes => hir::IsAsync::Async(span),
Asyncness::No => hir::IsAsync::NotAsync,
};
hir::FnHeader {
unsafety: sig.unsafety,
constness: self.tcx.constness(sig_id),
asyncness,
abi: sig.abi,
}
};
hir::FnSig { decl, header, span }
}
fn generate_param(&mut self, ty: &'hir hir::Ty<'hir>) -> (hir::Param<'hir>, NodeId) {
fn generate_param(&mut self, span: Span) -> (hir::Param<'hir>, NodeId) {
let pat_node_id = self.next_node_id();
let pat_id = self.lower_node_id(pat_node_id);
let pat = self.arena.alloc(hir::Pat {
hir_id: pat_id,
kind: hir::PatKind::Binding(hir::BindingMode::NONE, pat_id, Ident::empty(), None),
span: ty.span,
span,
default_binding_modes: false,
});
(hir::Param { hir_id: self.next_id(), pat, ty_span: ty.span, span: ty.span }, pat_node_id)
(hir::Param { hir_id: self.next_id(), pat, ty_span: span, span }, pat_node_id)
}
fn generate_arg(&mut self, ty: &'hir hir::Ty<'hir>, param_id: HirId) -> hir::Expr<'hir> {
fn generate_arg(&mut self, param_id: HirId, span: Span) -> hir::Expr<'hir> {
let segments = self.arena.alloc_from_iter(iter::once(hir::PathSegment {
ident: Ident::empty(),
hir_id: self.next_id(),
@ -195,20 +219,20 @@ impl<'hir> LoweringContext<'_, 'hir> {
infer_args: false,
}));
let path =
self.arena.alloc(hir::Path { span: ty.span, res: Res::Local(param_id), segments });
let path = self.arena.alloc(hir::Path { span, res: Res::Local(param_id), segments });
hir::Expr {
hir_id: self.next_id(),
kind: hir::ExprKind::Path(hir::QPath::Resolved(None, path)),
span: ty.span,
span,
}
}
fn lower_delegation_body(
&mut self,
decl: &'hir hir::FnDecl<'hir>,
delegation: &Delegation,
param_count: usize,
span: Span,
) -> BodyId {
let path = self.lower_qpath(
delegation.id,
@ -224,8 +248,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
let mut parameters: Vec<hir::Param<'_>> = Vec::new();
let mut args: Vec<hir::Expr<'hir>> = Vec::new();
for (idx, param_ty) in decl.inputs.iter().enumerate() {
let (param, pat_node_id) = this.generate_param(param_ty);
for idx in 0..param_count {
let (param, pat_node_id) = this.generate_param(span);
parameters.push(param);
let arg = if let Some(block) = block
@ -245,7 +269,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
}
} else {
let pat_hir_id = this.lower_node_id(pat_node_id);
this.generate_arg(param_ty, pat_hir_id)
this.generate_arg(pat_hir_id, span)
};
args.push(arg);
}
@ -304,7 +328,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
implicit_self: hir::ImplicitSelfKind::None,
});
let sig = self.lower_delegation_sig(span, decl);
let header = self.generate_header_error();
let sig = hir::FnSig { decl, header, span };
let body_id = self.lower_body(|this| {
let expr =
hir::Expr { hir_id: this.next_id(), kind: hir::ExprKind::Err(err), span: span };
@ -312,6 +338,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
});
DelegationResults { generics, body_id, sig }
}
fn generate_header_error(&self) -> hir::FnHeader {
hir::FnHeader {
unsafety: hir::Unsafety::Normal,
constness: hir::Constness::NotConst,
asyncness: hir::IsAsync::NotAsync,
abi: abi::Abi::Rust,
}
}
}
struct SelfResolver<'a> {

2
compiler/rustc_ast_lowering/src/item.rs
View file

@ -1344,7 +1344,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
(generics, hir::FnSig { header, decl, span: self.lower_span(sig.span) })
}
fn lower_fn_header(&mut self, h: FnHeader) -> hir::FnHeader {
pub(super) fn lower_fn_header(&mut self, h: FnHeader) -> hir::FnHeader {
let asyncness = if let Some(CoroutineKind::Async { span, .. }) = h.coroutine_kind {
hir::IsAsync::Async(span)
} else {