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Rollup merge of #67922 - Centril:lowering-cleanup, r=petrochenkov

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rustc_ast_lowering: misc cleanup & rustc dep reductions

- The first two commits do some code simplification.
- The next three do some file splitting (getting `lib.rs` below the 3kloc tidy lint).
- The remaining commits reduce the number of `rustc::` imports. This works towards making lowering independent of the `rustc` crate.

r? @oli-obk cc @Zoxc
This commit is contained in:
Mazdak Farrokhzad 2020-01-10 02:47:33 +01:00 • committed by GitHub
commit 3bfa28c3a8
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GPG key ID: 4AEE18F83AFDEB23
22 changed files with 752 additions and 748 deletions
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2
src/librustc/infer/canonical/query_response.rs
View file

@ -22,7 +22,7 @@ use crate::traits::{Obligation, ObligationCause, PredicateObligation};
use crate::ty::fold::TypeFoldable;
use crate::ty::subst::{GenericArg, GenericArgKind};
use crate::ty::{self, BoundVar, Ty, TyCtxt};
use crate::util::captures::Captures;
use rustc_data_structures::captures::Captures;
use rustc_index::vec::Idx;
use rustc_index::vec::IndexVec;
use rustc_span::DUMMY_SP;

2
src/librustc/infer/outlives/verify.rs
View file

@ -3,7 +3,7 @@ use crate::infer::{GenericKind, VerifyBound};
use crate::traits;
use crate::ty::subst::{InternalSubsts, Subst};
use crate::ty::{self, Ty, TyCtxt};
use crate::util::captures::Captures;
use rustc_data_structures::captures::Captures;
use rustc_hir::def_id::DefId;
/// The `TypeOutlives` struct has the job of "lowering" a `T: 'a`

1
src/librustc/lib.rs
View file

@ -100,7 +100,6 @@ pub mod ty;
pub mod util {
pub mod bug;
pub mod captures;
pub mod common;
}

5
src/librustc/middle/cstore.rs
View file

@ -5,8 +5,8 @@
use crate::hir::map as hir_map;
use crate::hir::map::definitions::{DefKey, DefPathTable};
use crate::session::search_paths::PathKind;
use crate::session::{CrateDisambiguator, Session};
use crate::ty::{self, TyCtxt};
use crate::session::CrateDisambiguator;
use crate::ty::TyCtxt;
use rustc_data_structures::svh::Svh;
use rustc_data_structures::sync::{self, MetadataRef};
@ -208,7 +208,6 @@ pub trait CrateStore {
fn crate_is_private_dep_untracked(&self, cnum: CrateNum) -> bool;
fn crate_disambiguator_untracked(&self, cnum: CrateNum) -> CrateDisambiguator;
fn crate_hash_untracked(&self, cnum: CrateNum) -> Svh;
fn item_generics_cloned_untracked(&self, def: DefId, sess: &Session) -> ty::Generics;
// This is basically a 1-based range of ints, which is a little
// silly - I may fix that.

3
src/librustc/traits/project.rs
View file

@ -17,7 +17,6 @@ use crate::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
use crate::ty::fold::{TypeFoldable, TypeFolder};
use crate::ty::subst::{InternalSubsts, Subst};
use crate::ty::{self, ToPolyTraitRef, ToPredicate, Ty, TyCtxt};
use crate::util::common::FN_OUTPUT_NAME;
use rustc_data_structures::snapshot_map::{Snapshot, SnapshotMap};
use rustc_hir::def_id::DefId;
use rustc_macros::HashStable;
@ -1364,7 +1363,7 @@ fn confirm_callable_candidate<'cx, 'tcx>(
projection_ty: ty::ProjectionTy::from_ref_and_name(
tcx,
trait_ref,
Ident::with_dummy_span(FN_OUTPUT_NAME),
Ident::with_dummy_span(rustc_hir::FN_OUTPUT_NAME),
),
ty: ret_type,
});

2
src/librustc/ty/mod.rs
View file

@ -26,8 +26,8 @@ use crate::ty::layout::VariantIdx;
use crate::ty::subst::{InternalSubsts, Subst, SubstsRef};
use crate::ty::util::{Discr, IntTypeExt};
use crate::ty::walk::TypeWalker;
use crate::util::captures::Captures;
use arena::SyncDroplessArena;
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::fx::FxIndexMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};

5
src/librustc/ty/sty.rs
View file

@ -13,11 +13,10 @@ use crate::ty::layout::VariantIdx;
use crate::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Subst, SubstsRef};
use crate::ty::{self, AdtDef, DefIdTree, Discr, Ty, TyCtxt, TypeFlags, TypeFoldable};
use crate::ty::{List, ParamEnv, ParamEnvAnd, TyS};
use crate::util::captures::Captures;
use polonius_engine::Atom;
use rustc_data_structures::captures::Captures;
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use polonius_engine::Atom;
use rustc_index::vec::Idx;
use rustc_macros::HashStable;
use rustc_span::symbol::{kw, Symbol};

5
src/librustc/util/common.rs
View file

@ -5,14 +5,9 @@ use rustc_data_structures::sync::Lock;
use std::fmt::Debug;
use std::time::{Duration, Instant};
use rustc_span::symbol::{sym, Symbol};
#[cfg(test)]
mod tests;
// The name of the associated type for `Fn` return types.
pub const FN_OUTPUT_NAME: Symbol = sym::Output;
pub use errors::ErrorReported;
pub fn to_readable_str(mut val: usize) -> String {

11
src/librustc_ast_lowering/item.rs
View file

@ -25,19 +25,16 @@ pub(super) struct ItemLowerer<'a, 'lowering, 'hir> {
pub(super) lctx: &'a mut LoweringContext<'lowering, 'hir>,
}
impl<'a, 'lowering, 'hir> ItemLowerer<'a, 'lowering, 'hir> {
fn with_trait_impl_ref<F>(&mut self, trait_impl_ref: &Option<TraitRef>, f: F)
where
F: FnOnce(&mut Self),
{
impl ItemLowerer<'_, '_, '_> {
fn with_trait_impl_ref(&mut self, impl_ref: &Option<TraitRef>, f: impl FnOnce(&mut Self)) {
let old = self.lctx.is_in_trait_impl;
self.lctx.is_in_trait_impl = if let &None = trait_impl_ref { false } else { true };
self.lctx.is_in_trait_impl = if let &None = impl_ref { false } else { true };
f(self);
self.lctx.is_in_trait_impl = old;
}
}
impl<'a, 'lowering, 'hir> Visitor<'a> for ItemLowerer<'a, 'lowering, 'hir> {
impl<'a> Visitor<'a> for ItemLowerer<'a, '_, '_> {
fn visit_mod(&mut self, m: &'a Mod, _s: Span, _attrs: &[Attribute], n: NodeId) {
let hir_id = self.lctx.lower_node_id(n);

747
src/librustc_ast_lowering/lib.rs
View file

@ -1,5 +1,3 @@
// ignore-tidy-filelength
//! Lowers the AST to the HIR.
//!
//! Since the AST and HIR are fairly similar, this is mostly a simple procedure,
@ -33,21 +31,20 @@
//! in the HIR, especially for multiple identifiers.
#![feature(array_value_iter)]
#![feature(crate_visibility_modifier)]
use rustc::arena::Arena;
use rustc::dep_graph::DepGraph;
use rustc::hir::map::definitions::{DefKey, DefPathData, Definitions};
use rustc::hir::map::Map;
use rustc::lint;
use rustc::lint::builtin::{self, ELIDED_LIFETIMES_IN_PATHS};
use rustc::middle::cstore::CrateStore;
use rustc::util::captures::Captures;
use rustc::util::common::FN_OUTPUT_NAME;
use rustc::lint::builtin;
use rustc::{bug, span_bug};
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fx::FxHashSet;
use rustc_data_structures::sync::Lrc;
use rustc_error_codes::*;
use rustc_errors::{struct_span_err, Applicability};
use rustc_errors::struct_span_err;
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Namespace, PartialRes, PerNS, Res};
use rustc_hir::def_id::{DefId, DefIdMap, DefIndex, CRATE_DEF_INDEX};
@ -58,14 +55,13 @@ use rustc_session::config::nightly_options;
use rustc_session::node_id::NodeMap;
use rustc_session::Session;
use rustc_span::hygiene::ExpnId;
use rustc_span::source_map::{respan, DesugaringKind, ExpnData, ExpnKind, Spanned};
use rustc_span::source_map::{respan, DesugaringKind, ExpnData, ExpnKind};
use rustc_span::symbol::{kw, sym, Symbol};
use rustc_span::Span;
use syntax::ast;
use syntax::ast::*;
use syntax::attr;
use syntax::print::pprust;
use syntax::ptr::P as AstP;
use syntax::sess::ParseSess;
use syntax::token::{self, Nonterminal, Token};
use syntax::tokenstream::{TokenStream, TokenTree};
@ -86,6 +82,8 @@ macro_rules! arena_vec {
mod expr;
mod item;
mod pat;
mod path;
const HIR_ID_COUNTER_LOCKED: u32 = 0xFFFFFFFF;
@ -173,7 +171,9 @@ struct LoweringContext<'a, 'hir: 'a> {
}
pub trait Resolver {
fn cstore(&self) -> &dyn CrateStore;
fn def_key(&mut self, id: DefId) -> DefKey;
fn item_generics_num_lifetimes(&self, def: DefId, sess: &Session) -> usize;
/// Obtains resolution for a `NodeId` with a single resolution.
fn get_partial_res(&mut self, id: NodeId) -> Option<PartialRes>;
@ -433,10 +433,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
}
fn with_hir_id_owner<F, T>(&mut self, owner: Option<NodeId>, f: F) -> T
where
F: FnOnce(&mut Self) -> T,
{
fn with_hir_id_owner<T>(
&mut self,
owner: Option<NodeId>,
f: impl FnOnce(&mut Self) -> T,
) -> T {
let old = mem::replace(&mut self.hir_id_owner, owner);
let r = f(self);
self.hir_id_owner = old;
@ -444,7 +445,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
}
impl<'tcx, 'lowering, 'hir> Visitor<'tcx> for MiscCollector<'tcx, 'lowering, 'hir> {
impl<'tcx> Visitor<'tcx> for MiscCollector<'tcx, '_, '_> {
fn visit_pat(&mut self, p: &'tcx Pat) {
if let PatKind::Paren(..) | PatKind::Rest = p.kind {
// Doesn't generate a HIR node
@ -577,10 +578,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
lowered
}
fn lower_node_id_generic<F>(&mut self, ast_node_id: NodeId, alloc_hir_id: F) -> hir::HirId
where
F: FnOnce(&mut Self) -> hir::HirId,
{
fn lower_node_id_generic(
&mut self,
ast_node_id: NodeId,
alloc_hir_id: impl FnOnce(&mut Self) -> hir::HirId,
) -> hir::HirId {
if ast_node_id == DUMMY_NODE_ID {
return hir::DUMMY_HIR_ID;
}
@ -604,10 +606,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
}
fn with_hir_id_owner<F, T>(&mut self, owner: NodeId, f: F) -> T
where
F: FnOnce(&mut Self) -> T,
{
fn with_hir_id_owner<T>(&mut self, owner: NodeId, f: impl FnOnce(&mut Self) -> T) -> T {
let counter = self
.item_local_id_counters
.insert(owner, HIR_ID_COUNTER_LOCKED)
@ -736,15 +735,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
/// Presuming that in-band lifetimes are enabled, then
/// `self.anonymous_lifetime_mode` will be updated to match the
/// parameter while `f` is running (and restored afterwards).
fn collect_in_band_defs<T, F>(
fn collect_in_band_defs<T>(
&mut self,
parent_id: DefId,
anonymous_lifetime_mode: AnonymousLifetimeMode,
f: F,
) -> (Vec<hir::GenericParam<'hir>>, T)
where
F: FnOnce(&mut Self) -> (Vec<hir::GenericParam<'hir>>, T),
{
f: impl FnOnce(&mut Self) -> (Vec<hir::GenericParam<'hir>>, T),
) -> (Vec<hir::GenericParam<'hir>>, T) {
assert!(!self.is_collecting_in_band_lifetimes);
assert!(self.lifetimes_to_define.is_empty());
let old_anonymous_lifetime_mode = self.anonymous_lifetime_mode;
@ -847,10 +843,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// This is used to track which lifetimes have already been defined, and
// which are new in-band lifetimes that need to have a definition created
// for them.
fn with_in_scope_lifetime_defs<T, F>(&mut self, params: &[GenericParam], f: F) -> T
where
F: FnOnce(&mut Self) -> T,
{
fn with_in_scope_lifetime_defs<T>(
&mut self,
params: &[GenericParam],
f: impl FnOnce(&mut Self) -> T,
) -> T {
let old_len = self.in_scope_lifetimes.len();
let lt_def_names = params.iter().filter_map(|param| match param.kind {
GenericParamKind::Lifetime { .. } => Some(ParamName::Plain(param.ident.modern())),
@ -870,16 +867,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
/// Presuming that in-band lifetimes are enabled, then
/// `self.anonymous_lifetime_mode` will be updated to match the
/// parameter while `f` is running (and restored afterwards).
fn add_in_band_defs<F, T>(
fn add_in_band_defs<T>(
&mut self,
generics: &Generics,
parent_id: DefId,
anonymous_lifetime_mode: AnonymousLifetimeMode,
f: F,
) -> (hir::Generics<'hir>, T)
where
F: FnOnce(&mut Self, &mut Vec<hir::GenericParam<'hir>>) -> T,
{
f: impl FnOnce(&mut Self, &mut Vec<hir::GenericParam<'hir>>) -> T,
) -> (hir::Generics<'hir>, T) {
let (in_band_defs, (mut lowered_generics, res)) =
self.with_in_scope_lifetime_defs(&generics.params, |this| {
this.collect_in_band_defs(parent_id, anonymous_lifetime_mode, |this| {
@ -917,10 +911,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
(lowered_generics, res)
}
fn with_dyn_type_scope<T, F>(&mut self, in_scope: bool, f: F) -> T
where
F: FnOnce(&mut Self) -> T,
{
fn with_dyn_type_scope<T>(&mut self, in_scope: bool, f: impl FnOnce(&mut Self) -> T) -> T {
let was_in_dyn_type = self.is_in_dyn_type;
self.is_in_dyn_type = in_scope;
@ -931,10 +922,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
result
}
fn with_new_scopes<T, F>(&mut self, f: F) -> T
where
F: FnOnce(&mut Self) -> T,
{
fn with_new_scopes<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
let was_in_loop_condition = self.is_in_loop_condition;
self.is_in_loop_condition = false;
@ -949,14 +937,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
ret
}
fn def_key(&mut self, id: DefId) -> DefKey {
if id.is_local() {
self.resolver.definitions().def_key(id.index)
} else {
self.resolver.cstore().def_key(id)
}
}
fn lower_attrs(&mut self, attrs: &[Attribute]) -> &'hir [Attribute] {
self.arena.alloc_from_iter(attrs.iter().map(|a| self.lower_attr(a)))
}
@ -1635,403 +1615,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
)
}
fn lower_qpath(
&mut self,
id: NodeId,
qself: &Option<QSelf>,
p: &Path,
param_mode: ParamMode,
mut itctx: ImplTraitContext<'_, 'hir>,
) -> hir::QPath<'hir> {
let qself_position = qself.as_ref().map(|q| q.position);
let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx.reborrow()));
let partial_res =
self.resolver.get_partial_res(id).unwrap_or_else(|| PartialRes::new(Res::Err));
let proj_start = p.segments.len() - partial_res.unresolved_segments();
let path = self.arena.alloc(hir::Path {
res: self.lower_res(partial_res.base_res()),
segments: self.arena.alloc_from_iter(p.segments[..proj_start].iter().enumerate().map(
|(i, segment)| {
let param_mode = match (qself_position, param_mode) {
(Some(j), ParamMode::Optional) if i < j => {
// This segment is part of the trait path in a
// qualified path - one of `a`, `b` or `Trait`
// in `<X as a::b::Trait>::T::U::method`.
ParamMode::Explicit
}
_ => param_mode,
};
// Figure out if this is a type/trait segment,
// which may need lifetime elision performed.
let parent_def_id = |this: &mut Self, def_id: DefId| DefId {
krate: def_id.krate,
index: this.def_key(def_id).parent.expect("missing parent"),
};
let type_def_id = match partial_res.base_res() {
Res::Def(DefKind::AssocTy, def_id) if i + 2 == proj_start => {
Some(parent_def_id(self, def_id))
}
Res::Def(DefKind::Variant, def_id) if i + 1 == proj_start => {
Some(parent_def_id(self, def_id))
}
Res::Def(DefKind::Struct, def_id)
| Res::Def(DefKind::Union, def_id)
| Res::Def(DefKind::Enum, def_id)
| Res::Def(DefKind::TyAlias, def_id)
| Res::Def(DefKind::Trait, def_id)
if i + 1 == proj_start =>
{
Some(def_id)
}
_ => None,
};
let parenthesized_generic_args = match partial_res.base_res() {
// `a::b::Trait(Args)`
Res::Def(DefKind::Trait, _) if i + 1 == proj_start => {
ParenthesizedGenericArgs::Ok
}
// `a::b::Trait(Args)::TraitItem`
Res::Def(DefKind::Method, _)
| Res::Def(DefKind::AssocConst, _)
| Res::Def(DefKind::AssocTy, _)
if i + 2 == proj_start =>
{
ParenthesizedGenericArgs::Ok
}
// Avoid duplicated errors.
Res::Err => ParenthesizedGenericArgs::Ok,
// An error
_ => ParenthesizedGenericArgs::Err,
};
let num_lifetimes = type_def_id.map_or(0, |def_id| {
if let Some(&n) = self.type_def_lifetime_params.get(&def_id) {
return n;
}
assert!(!def_id.is_local());
let item_generics = self
.resolver
.cstore()
.item_generics_cloned_untracked(def_id, self.sess);
let n = item_generics.own_counts().lifetimes;
self.type_def_lifetime_params.insert(def_id, n);
n
});
self.lower_path_segment(
p.span,
segment,
param_mode,
num_lifetimes,
parenthesized_generic_args,
itctx.reborrow(),
None,
)
},
)),
span: p.span,
});
// Simple case, either no projections, or only fully-qualified.
// E.g., `std::mem::size_of` or `<I as Iterator>::Item`.
if partial_res.unresolved_segments() == 0 {
return hir::QPath::Resolved(qself, path);
}
// Create the innermost type that we're projecting from.
let mut ty = if path.segments.is_empty() {
// If the base path is empty that means there exists a
// syntactical `Self`, e.g., `&i32` in `<&i32>::clone`.
qself.expect("missing QSelf for <T>::...")
} else {
// Otherwise, the base path is an implicit `Self` type path,
// e.g., `Vec` in `Vec::new` or `<I as Iterator>::Item` in
// `<I as Iterator>::Item::default`.
let new_id = self.next_id();
self.arena.alloc(self.ty_path(new_id, p.span, hir::QPath::Resolved(qself, path)))
};
// Anything after the base path are associated "extensions",
// out of which all but the last one are associated types,
// e.g., for `std::vec::Vec::<T>::IntoIter::Item::clone`:
// * base path is `std::vec::Vec<T>`
// * "extensions" are `IntoIter`, `Item` and `clone`
// * type nodes are:
// 1. `std::vec::Vec<T>` (created above)
// 2. `<std::vec::Vec<T>>::IntoIter`
// 3. `<<std::vec::Vec<T>>::IntoIter>::Item`
// * final path is `<<<std::vec::Vec<T>>::IntoIter>::Item>::clone`
for (i, segment) in p.segments.iter().enumerate().skip(proj_start) {
let segment = self.arena.alloc(self.lower_path_segment(
p.span,
segment,
param_mode,
0,
ParenthesizedGenericArgs::Err,
itctx.reborrow(),
None,
));
let qpath = hir::QPath::TypeRelative(ty, segment);
// It's finished, return the extension of the right node type.
if i == p.segments.len() - 1 {
return qpath;
}
// Wrap the associated extension in another type node.
let new_id = self.next_id();
ty = self.arena.alloc(self.ty_path(new_id, p.span, qpath));
}
// We should've returned in the for loop above.
span_bug!(
p.span,
"lower_qpath: no final extension segment in {}..{}",
proj_start,
p.segments.len()
)
}
fn lower_path_extra(
&mut self,
res: Res,
p: &Path,
param_mode: ParamMode,
explicit_owner: Option<NodeId>,
) -> &'hir hir::Path<'hir> {
self.arena.alloc(hir::Path {
res,
segments: self.arena.alloc_from_iter(p.segments.iter().map(|segment| {
self.lower_path_segment(
p.span,
segment,
param_mode,
0,
ParenthesizedGenericArgs::Err,
ImplTraitContext::disallowed(),
explicit_owner,
)
})),
span: p.span,
})
}
fn lower_path(&mut self, id: NodeId, p: &Path, param_mode: ParamMode) -> &'hir hir::Path<'hir> {
let res = self.expect_full_res(id);
let res = self.lower_res(res);
self.lower_path_extra(res, p, param_mode, None)
}
fn lower_path_segment(
&mut self,
path_span: Span,
segment: &PathSegment,
param_mode: ParamMode,
expected_lifetimes: usize,
parenthesized_generic_args: ParenthesizedGenericArgs,
itctx: ImplTraitContext<'_, 'hir>,
explicit_owner: Option<NodeId>,
) -> hir::PathSegment<'hir> {
let (mut generic_args, infer_args) = if let Some(ref generic_args) = segment.args {
let msg = "parenthesized type parameters may only be used with a `Fn` trait";
match **generic_args {
GenericArgs::AngleBracketed(ref data) => {
self.lower_angle_bracketed_parameter_data(data, param_mode, itctx)
}
GenericArgs::Parenthesized(ref data) => match parenthesized_generic_args {
ParenthesizedGenericArgs::Ok => self.lower_parenthesized_parameter_data(data),
ParenthesizedGenericArgs::Err => {
let mut err = struct_span_err!(self.sess, data.span, E0214, "{}", msg);
err.span_label(data.span, "only `Fn` traits may use parentheses");
if let Ok(snippet) = self.sess.source_map().span_to_snippet(data.span) {
// Do not suggest going from `Trait()` to `Trait<>`
if data.inputs.len() > 0 {
if let Some(split) = snippet.find('(') {
let trait_name = &snippet[0..split];
let args = &snippet[split + 1..snippet.len() - 1];
err.span_suggestion(
data.span,
"use angle brackets instead",
format!("{}<{}>", trait_name, args),
Applicability::MaybeIncorrect,
);
}
}
};
err.emit();
(
self.lower_angle_bracketed_parameter_data(
&data.as_angle_bracketed_args(),
param_mode,
itctx,
)
.0,
false,
)
}
},
}
} else {
self.lower_angle_bracketed_parameter_data(&Default::default(), param_mode, itctx)
};
let has_lifetimes = generic_args.args.iter().any(|arg| match arg {
GenericArg::Lifetime(_) => true,
_ => false,
});
let first_generic_span = generic_args
.args
.iter()
.map(|a| a.span())
.chain(generic_args.bindings.iter().map(|b| b.span))
.next();
if !generic_args.parenthesized && !has_lifetimes {
generic_args.args = self
.elided_path_lifetimes(path_span, expected_lifetimes)
.map(|lt| GenericArg::Lifetime(lt))
.chain(generic_args.args.into_iter())
.collect();
if expected_lifetimes > 0 && param_mode == ParamMode::Explicit {
let anon_lt_suggestion = vec!["'_"; expected_lifetimes].join(", ");
let no_non_lt_args = generic_args.args.len() == expected_lifetimes;
let no_bindings = generic_args.bindings.is_empty();
let (incl_angl_brckt, insertion_sp, suggestion) = if no_non_lt_args && no_bindings {
// If there are no (non-implicit) generic args or associated type
// bindings, our suggestion includes the angle brackets.
(true, path_span.shrink_to_hi(), format!("<{}>", anon_lt_suggestion))
} else {
// Otherwise (sorry, this is kind of gross) we need to infer the
// place to splice in the `'_, ` from the generics that do exist.
let first_generic_span = first_generic_span
.expect("already checked that non-lifetime args or bindings exist");
(false, first_generic_span.shrink_to_lo(), format!("{}, ", anon_lt_suggestion))
};
match self.anonymous_lifetime_mode {
// In create-parameter mode we error here because we don't want to support
// deprecated impl elision in new features like impl elision and `async fn`,
// both of which work using the `CreateParameter` mode:
//
// impl Foo for std::cell::Ref<u32> // note lack of '_
// async fn foo(_: std::cell::Ref<u32>) { ... }
AnonymousLifetimeMode::CreateParameter => {
let mut err = struct_span_err!(
self.sess,
path_span,
E0726,
"implicit elided lifetime not allowed here"
);
crate::lint::builtin::add_elided_lifetime_in_path_suggestion(
&self.sess,
&mut err,
expected_lifetimes,
path_span,
incl_angl_brckt,
insertion_sp,
suggestion,
);
err.emit();
}
AnonymousLifetimeMode::PassThrough | AnonymousLifetimeMode::ReportError => {
self.resolver.lint_buffer().buffer_lint_with_diagnostic(
ELIDED_LIFETIMES_IN_PATHS,
CRATE_NODE_ID,
path_span,
"hidden lifetime parameters in types are deprecated",
builtin::BuiltinLintDiagnostics::ElidedLifetimesInPaths(
expected_lifetimes,
path_span,
incl_angl_brckt,
insertion_sp,
suggestion,
),
);
}
}
}
}
let res = self.expect_full_res(segment.id);
let id = if let Some(owner) = explicit_owner {
self.lower_node_id_with_owner(segment.id, owner)
} else {
self.lower_node_id(segment.id)
};
debug!(
"lower_path_segment: ident={:?} original-id={:?} new-id={:?}",
segment.ident, segment.id, id,
);
hir::PathSegment {
ident: segment.ident,
hir_id: Some(id),
res: Some(self.lower_res(res)),
infer_args,
args: if generic_args.is_empty() {
None
} else {
Some(self.arena.alloc(generic_args.into_generic_args(self.arena)))
},
}
}
fn lower_angle_bracketed_parameter_data(
&mut self,
data: &AngleBracketedArgs,
param_mode: ParamMode,
mut itctx: ImplTraitContext<'_, 'hir>,
) -> (GenericArgsCtor<'hir>, bool) {
let &AngleBracketedArgs { ref args, ref constraints, .. } = data;
let has_non_lt_args = args.iter().any(|arg| match arg {
ast::GenericArg::Lifetime(_) => false,
ast::GenericArg::Type(_) => true,
ast::GenericArg::Const(_) => true,
});
(
GenericArgsCtor {
args: args.iter().map(|a| self.lower_generic_arg(a, itctx.reborrow())).collect(),
bindings: self.arena.alloc_from_iter(
constraints.iter().map(|b| self.lower_assoc_ty_constraint(b, itctx.reborrow())),
),
parenthesized: false,
},
!has_non_lt_args && param_mode == ParamMode::Optional,
)
}
fn lower_parenthesized_parameter_data(
&mut self,
data: &ParenthesizedArgs,
) -> (GenericArgsCtor<'hir>, bool) {
// Switch to `PassThrough` mode for anonymous lifetimes; this
// means that we permit things like `&Ref<T>`, where `Ref` has
// a hidden lifetime parameter. This is needed for backwards
// compatibility, even in contexts like an impl header where
// we generally don't permit such things (see #51008).
self.with_anonymous_lifetime_mode(AnonymousLifetimeMode::PassThrough, |this| {
let &ParenthesizedArgs { ref inputs, ref output, span } = data;
let inputs = this.arena.alloc_from_iter(
inputs.iter().map(|ty| this.lower_ty_direct(ty, ImplTraitContext::disallowed())),
);
let output_ty = match output {
FunctionRetTy::Ty(ty) => this.lower_ty(&ty, ImplTraitContext::disallowed()),
FunctionRetTy::Default(_) => this.arena.alloc(this.ty_tup(span, &[])),
};
let args = smallvec![GenericArg::Type(this.ty_tup(span, inputs))];
let binding = hir::TypeBinding {
hir_id: this.next_id(),
ident: Ident::with_dummy_span(FN_OUTPUT_NAME),
span: output_ty.span,
kind: hir::TypeBindingKind::Equality { ty: output_ty },
};
(
GenericArgsCtor { args, bindings: arena_vec![this; binding], parenthesized: true },
false,
)
})
}
fn lower_local(&mut self, l: &Local) -> (hir::Local<'hir>, SmallVec<[NodeId; 1]>) {
let mut ids = SmallVec::<[NodeId; 1]>::new();
if self.sess.features_untracked().impl_trait_in_bindings {
@ -2387,12 +1970,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// "<Output = T>"
let future_params = self.arena.alloc(hir::GenericArgs {
args: &[],
bindings: arena_vec![self; hir::TypeBinding {
ident: Ident::with_dummy_span(FN_OUTPUT_NAME),
kind: hir::TypeBindingKind::Equality { ty: output_ty },
hir_id: self.next_id(),
span,
}],
bindings: arena_vec![self; self.output_ty_binding(span, output_ty)],
parenthesized: false,
});
@ -2652,250 +2230,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
self.expr_block(block, AttrVec::new())
}
fn lower_pat(&mut self, p: &Pat) -> &'hir hir::Pat<'hir> {
let node = match p.kind {
PatKind::Wild => hir::PatKind::Wild,
PatKind::Ident(ref binding_mode, ident, ref sub) => {
let lower_sub = |this: &mut Self| sub.as_ref().map(|s| this.lower_pat(&*s));
let node = self.lower_pat_ident(p, binding_mode, ident, lower_sub);
node
}
PatKind::Lit(ref e) => hir::PatKind::Lit(self.lower_expr(e)),
PatKind::TupleStruct(ref path, ref pats) => {
let qpath = self.lower_qpath(
p.id,
&None,
path,
ParamMode::Optional,
ImplTraitContext::disallowed(),
);
let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple struct");
hir::PatKind::TupleStruct(qpath, pats, ddpos)
}
PatKind::Or(ref pats) => {
hir::PatKind::Or(self.arena.alloc_from_iter(pats.iter().map(|x| self.lower_pat(x))))
}
PatKind::Path(ref qself, ref path) => {
let qpath = self.lower_qpath(
p.id,
qself,
path,
ParamMode::Optional,
ImplTraitContext::disallowed(),
);
hir::PatKind::Path(qpath)
}
PatKind::Struct(ref path, ref fields, etc) => {
let qpath = self.lower_qpath(
p.id,
&None,
path,
ParamMode::Optional,
ImplTraitContext::disallowed(),
);
let fs = self.arena.alloc_from_iter(fields.iter().map(|f| hir::FieldPat {
hir_id: self.next_id(),
ident: f.ident,
pat: self.lower_pat(&f.pat),
is_shorthand: f.is_shorthand,
span: f.span,
}));
hir::PatKind::Struct(qpath, fs, etc)
}
PatKind::Tuple(ref pats) => {
let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple");
hir::PatKind::Tuple(pats, ddpos)
}
PatKind::Box(ref inner) => hir::PatKind::Box(self.lower_pat(inner)),
PatKind::Ref(ref inner, mutbl) => hir::PatKind::Ref(self.lower_pat(inner), mutbl),
PatKind::Range(ref e1, ref e2, Spanned { node: ref end, .. }) => hir::PatKind::Range(
self.lower_expr(e1),
self.lower_expr(e2),
self.lower_range_end(end),
),
PatKind::Slice(ref pats) => self.lower_pat_slice(pats),
PatKind::Rest => {
// If we reach here the `..` pattern is not semantically allowed.
self.ban_illegal_rest_pat(p.span)
}
PatKind::Paren(ref inner) => return self.lower_pat(inner),
PatKind::Mac(_) => panic!("Shouldn't exist here"),
};
self.pat_with_node_id_of(p, node)
}
fn lower_pat_tuple(
&mut self,
pats: &[AstP<Pat>],
ctx: &str,
) -> (&'hir [&'hir hir::Pat<'hir>], Option<usize>) {
let mut elems = Vec::with_capacity(pats.len());
let mut rest = None;
let mut iter = pats.iter().enumerate();
for (idx, pat) in iter.by_ref() {
// Interpret the first `..` pattern as a sub-tuple pattern.
// Note that unlike for slice patterns,
// where `xs @ ..` is a legal sub-slice pattern,
// it is not a legal sub-tuple pattern.
if pat.is_rest() {
rest = Some((idx, pat.span));
break;
}
// It was not a sub-tuple pattern so lower it normally.
elems.push(self.lower_pat(pat));
}
for (_, pat) in iter {
// There was a previous sub-tuple pattern; make sure we don't allow more...
if pat.is_rest() {
// ...but there was one again, so error.
self.ban_extra_rest_pat(pat.span, rest.unwrap().1, ctx);
} else {
elems.push(self.lower_pat(pat));
}
}
(self.arena.alloc_from_iter(elems), rest.map(|(ddpos, _)| ddpos))
}
/// Lower a slice pattern of form `[pat_0, ..., pat_n]` into
/// `hir::PatKind::Slice(before, slice, after)`.
///
/// When encountering `($binding_mode $ident @)? ..` (`slice`),
/// this is interpreted as a sub-slice pattern semantically.
/// Patterns that follow, which are not like `slice` -- or an error occurs, are in `after`.
fn lower_pat_slice(&mut self, pats: &[AstP<Pat>]) -> hir::PatKind<'hir> {
let mut before = Vec::new();
let mut after = Vec::new();
let mut slice = None;
let mut prev_rest_span = None;
let mut iter = pats.iter();
// Lower all the patterns until the first occurence of a sub-slice pattern.
for pat in iter.by_ref() {
match pat.kind {
// Found a sub-slice pattern `..`. Record, lower it to `_`, and stop here.
PatKind::Rest => {
prev_rest_span = Some(pat.span);
slice = Some(self.pat_wild_with_node_id_of(pat));
break;
}
// Found a sub-slice pattern `$binding_mode $ident @ ..`.
// Record, lower it to `$binding_mode $ident @ _`, and stop here.
PatKind::Ident(ref bm, ident, Some(ref sub)) if sub.is_rest() => {
prev_rest_span = Some(sub.span);
let lower_sub = |this: &mut Self| Some(this.pat_wild_with_node_id_of(sub));
let node = self.lower_pat_ident(pat, bm, ident, lower_sub);
slice = Some(self.pat_with_node_id_of(pat, node));
break;
}
// It was not a subslice pattern so lower it normally.
_ => before.push(self.lower_pat(pat)),
}
}
// Lower all the patterns after the first sub-slice pattern.
for pat in iter {
// There was a previous subslice pattern; make sure we don't allow more.
let rest_span = match pat.kind {
PatKind::Rest => Some(pat.span),
PatKind::Ident(.., Some(ref sub)) if sub.is_rest() => {
// The `HirValidator` is merciless; add a `_` pattern to avoid ICEs.
after.push(self.pat_wild_with_node_id_of(pat));
Some(sub.span)
}
_ => None,
};
if let Some(rest_span) = rest_span {
// We have e.g., `[a, .., b, ..]`. That's no good, error!
self.ban_extra_rest_pat(rest_span, prev_rest_span.unwrap(), "slice");
} else {
// Lower the pattern normally.
after.push(self.lower_pat(pat));
}
}
hir::PatKind::Slice(
self.arena.alloc_from_iter(before),
slice,
self.arena.alloc_from_iter(after),
)
}
fn lower_pat_ident(
&mut self,
p: &Pat,
binding_mode: &BindingMode,
ident: Ident,
lower_sub: impl FnOnce(&mut Self) -> Option<&'hir hir::Pat<'hir>>,
) -> hir::PatKind<'hir> {
match self.resolver.get_partial_res(p.id).map(|d| d.base_res()) {
// `None` can occur in body-less function signatures
res @ None | res @ Some(Res::Local(_)) => {
let canonical_id = match res {
Some(Res::Local(id)) => id,
_ => p.id,
};
hir::PatKind::Binding(
self.lower_binding_mode(binding_mode),
self.lower_node_id(canonical_id),
ident,
lower_sub(self),
)
}
Some(res) => hir::PatKind::Path(hir::QPath::Resolved(
None,
self.arena.alloc(hir::Path {
span: ident.span,
res: self.lower_res(res),
segments: arena_vec![self; hir::PathSegment::from_ident(ident)],
}),
)),
}
}
fn pat_wild_with_node_id_of(&mut self, p: &Pat) -> &'hir hir::Pat<'hir> {
self.pat_with_node_id_of(p, hir::PatKind::Wild)
}
/// Construct a `Pat` with the `HirId` of `p.id` lowered.
fn pat_with_node_id_of(&mut self, p: &Pat, kind: hir::PatKind<'hir>) -> &'hir hir::Pat<'hir> {
self.arena.alloc(hir::Pat { hir_id: self.lower_node_id(p.id), kind, span: p.span })
}
/// Emit a friendly error for extra `..` patterns in a tuple/tuple struct/slice pattern.
fn ban_extra_rest_pat(&self, sp: Span, prev_sp: Span, ctx: &str) {
self.diagnostic()
.struct_span_err(sp, &format!("`..` can only be used once per {} pattern", ctx))
.span_label(sp, &format!("can only be used once per {} pattern", ctx))
.span_label(prev_sp, "previously used here")
.emit();
}
/// Used to ban the `..` pattern in places it shouldn't be semantically.
fn ban_illegal_rest_pat(&self, sp: Span) -> hir::PatKind<'hir> {
self.diagnostic()
.struct_span_err(sp, "`..` patterns are not allowed here")
.note("only allowed in tuple, tuple struct, and slice patterns")
.emit();
// We're not in a list context so `..` can be reasonably treated
// as `_` because it should always be valid and roughly matches the
// intent of `..` (notice that the rest of a single slot is that slot).
hir::PatKind::Wild
}
fn lower_range_end(&mut self, e: &RangeEnd) -> hir::RangeEnd {
match *e {
RangeEnd::Included(_) => hir::RangeEnd::Included,
RangeEnd::Excluded => hir::RangeEnd::Excluded,
}
}
fn lower_anon_const(&mut self, c: &AnonConst) -> hir::AnonConst {
self.with_new_scopes(|this| hir::AnonConst {
hir_id: this.lower_node_id(c.id),
@ -2955,15 +2289,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
}
fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingAnnotation {
match *b {
BindingMode::ByValue(Mutability::Not) => hir::BindingAnnotation::Unannotated,
BindingMode::ByRef(Mutability::Not) => hir::BindingAnnotation::Ref,
BindingMode::ByValue(Mutability::Mut) => hir::BindingAnnotation::Mutable,
BindingMode::ByRef(Mutability::Mut) => hir::BindingAnnotation::RefMut,
}
}
fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource {
match u {
CompilerGenerated => hir::UnsafeSource::CompilerGenerated,

262
src/librustc_ast_lowering/pat.rs Normal file
View file

@ -0,0 +1,262 @@
use super::{ImplTraitContext, LoweringContext, ParamMode};
use rustc_hir as hir;
use rustc_hir::def::Res;
use rustc_span::{source_map::Spanned, Span};
use syntax::ast::*;
use syntax::ptr::P;
impl<'a, 'hir> LoweringContext<'a, 'hir> {
crate fn lower_pat(&mut self, p: &Pat) -> &'hir hir::Pat<'hir> {
let node = match p.kind {
PatKind::Wild => hir::PatKind::Wild,
PatKind::Ident(ref binding_mode, ident, ref sub) => {
let lower_sub = |this: &mut Self| sub.as_ref().map(|s| this.lower_pat(&*s));
let node = self.lower_pat_ident(p, binding_mode, ident, lower_sub);
node
}
PatKind::Lit(ref e) => hir::PatKind::Lit(self.lower_expr(e)),
PatKind::TupleStruct(ref path, ref pats) => {
let qpath = self.lower_qpath(
p.id,
&None,
path,
ParamMode::Optional,
ImplTraitContext::disallowed(),
);
let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple struct");
hir::PatKind::TupleStruct(qpath, pats, ddpos)
}
PatKind::Or(ref pats) => {
hir::PatKind::Or(self.arena.alloc_from_iter(pats.iter().map(|x| self.lower_pat(x))))
}
PatKind::Path(ref qself, ref path) => {
let qpath = self.lower_qpath(
p.id,
qself,
path,
ParamMode::Optional,
ImplTraitContext::disallowed(),
);
hir::PatKind::Path(qpath)
}
PatKind::Struct(ref path, ref fields, etc) => {
let qpath = self.lower_qpath(
p.id,
&None,
path,
ParamMode::Optional,
ImplTraitContext::disallowed(),
);
let fs = self.arena.alloc_from_iter(fields.iter().map(|f| hir::FieldPat {
hir_id: self.next_id(),
ident: f.ident,
pat: self.lower_pat(&f.pat),
is_shorthand: f.is_shorthand,
span: f.span,
}));
hir::PatKind::Struct(qpath, fs, etc)
}
PatKind::Tuple(ref pats) => {
let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple");
hir::PatKind::Tuple(pats, ddpos)
}
PatKind::Box(ref inner) => hir::PatKind::Box(self.lower_pat(inner)),
PatKind::Ref(ref inner, mutbl) => hir::PatKind::Ref(self.lower_pat(inner), mutbl),
PatKind::Range(ref e1, ref e2, Spanned { node: ref end, .. }) => hir::PatKind::Range(
self.lower_expr(e1),
self.lower_expr(e2),
self.lower_range_end(end),
),
PatKind::Slice(ref pats) => self.lower_pat_slice(pats),
PatKind::Rest => {
// If we reach here the `..` pattern is not semantically allowed.
self.ban_illegal_rest_pat(p.span)
}
PatKind::Paren(ref inner) => return self.lower_pat(inner),
PatKind::Mac(_) => panic!("Shouldn't exist here"),
};
self.pat_with_node_id_of(p, node)
}
fn lower_pat_tuple(
&mut self,
pats: &[P<Pat>],
ctx: &str,
) -> (&'hir [&'hir hir::Pat<'hir>], Option<usize>) {
let mut elems = Vec::with_capacity(pats.len());
let mut rest = None;
let mut iter = pats.iter().enumerate();
for (idx, pat) in iter.by_ref() {
// Interpret the first `..` pattern as a sub-tuple pattern.
// Note that unlike for slice patterns,
// where `xs @ ..` is a legal sub-slice pattern,
// it is not a legal sub-tuple pattern.
if pat.is_rest() {
rest = Some((idx, pat.span));
break;
}
// It was not a sub-tuple pattern so lower it normally.
elems.push(self.lower_pat(pat));
}
for (_, pat) in iter {
// There was a previous sub-tuple pattern; make sure we don't allow more...
if pat.is_rest() {
// ...but there was one again, so error.
self.ban_extra_rest_pat(pat.span, rest.unwrap().1, ctx);
} else {
elems.push(self.lower_pat(pat));
}
}
(self.arena.alloc_from_iter(elems), rest.map(|(ddpos, _)| ddpos))
}
/// Lower a slice pattern of form `[pat_0, ..., pat_n]` into
/// `hir::PatKind::Slice(before, slice, after)`.
///
/// When encountering `($binding_mode $ident @)? ..` (`slice`),
/// this is interpreted as a sub-slice pattern semantically.
/// Patterns that follow, which are not like `slice` -- or an error occurs, are in `after`.
fn lower_pat_slice(&mut self, pats: &[P<Pat>]) -> hir::PatKind<'hir> {
let mut before = Vec::new();
let mut after = Vec::new();
let mut slice = None;
let mut prev_rest_span = None;
let mut iter = pats.iter();
// Lower all the patterns until the first occurence of a sub-slice pattern.
for pat in iter.by_ref() {
match pat.kind {
// Found a sub-slice pattern `..`. Record, lower it to `_`, and stop here.
PatKind::Rest => {
prev_rest_span = Some(pat.span);
slice = Some(self.pat_wild_with_node_id_of(pat));
break;
}
// Found a sub-slice pattern `$binding_mode $ident @ ..`.
// Record, lower it to `$binding_mode $ident @ _`, and stop here.
PatKind::Ident(ref bm, ident, Some(ref sub)) if sub.is_rest() => {
prev_rest_span = Some(sub.span);
let lower_sub = |this: &mut Self| Some(this.pat_wild_with_node_id_of(sub));
let node = self.lower_pat_ident(pat, bm, ident, lower_sub);
slice = Some(self.pat_with_node_id_of(pat, node));
break;
}
// It was not a subslice pattern so lower it normally.
_ => before.push(self.lower_pat(pat)),
}
}
// Lower all the patterns after the first sub-slice pattern.
for pat in iter {
// There was a previous subslice pattern; make sure we don't allow more.
let rest_span = match pat.kind {
PatKind::Rest => Some(pat.span),
PatKind::Ident(.., Some(ref sub)) if sub.is_rest() => {
// The `HirValidator` is merciless; add a `_` pattern to avoid ICEs.
after.push(self.pat_wild_with_node_id_of(pat));
Some(sub.span)
}
_ => None,
};
if let Some(rest_span) = rest_span {
// We have e.g., `[a, .., b, ..]`. That's no good, error!
self.ban_extra_rest_pat(rest_span, prev_rest_span.unwrap(), "slice");
} else {
// Lower the pattern normally.
after.push(self.lower_pat(pat));
}
}
hir::PatKind::Slice(
self.arena.alloc_from_iter(before),
slice,
self.arena.alloc_from_iter(after),
)
}
fn lower_pat_ident(
&mut self,
p: &Pat,
binding_mode: &BindingMode,
ident: Ident,
lower_sub: impl FnOnce(&mut Self) -> Option<&'hir hir::Pat<'hir>>,
) -> hir::PatKind<'hir> {
match self.resolver.get_partial_res(p.id).map(|d| d.base_res()) {
// `None` can occur in body-less function signatures
res @ None | res @ Some(Res::Local(_)) => {
let canonical_id = match res {
Some(Res::Local(id)) => id,
_ => p.id,
};
hir::PatKind::Binding(
self.lower_binding_mode(binding_mode),
self.lower_node_id(canonical_id),
ident,
lower_sub(self),
)
}
Some(res) => hir::PatKind::Path(hir::QPath::Resolved(
None,
self.arena.alloc(hir::Path {
span: ident.span,
res: self.lower_res(res),
segments: arena_vec![self; hir::PathSegment::from_ident(ident)],
}),
)),
}
}
fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingAnnotation {
match *b {
BindingMode::ByValue(Mutability::Not) => hir::BindingAnnotation::Unannotated,
BindingMode::ByRef(Mutability::Not) => hir::BindingAnnotation::Ref,
BindingMode::ByValue(Mutability::Mut) => hir::BindingAnnotation::Mutable,
BindingMode::ByRef(Mutability::Mut) => hir::BindingAnnotation::RefMut,
}
}
fn pat_wild_with_node_id_of(&mut self, p: &Pat) -> &'hir hir::Pat<'hir> {
self.pat_with_node_id_of(p, hir::PatKind::Wild)
}
/// Construct a `Pat` with the `HirId` of `p.id` lowered.
fn pat_with_node_id_of(&mut self, p: &Pat, kind: hir::PatKind<'hir>) -> &'hir hir::Pat<'hir> {
self.arena.alloc(hir::Pat { hir_id: self.lower_node_id(p.id), kind, span: p.span })
}
/// Emit a friendly error for extra `..` patterns in a tuple/tuple struct/slice pattern.
fn ban_extra_rest_pat(&self, sp: Span, prev_sp: Span, ctx: &str) {
self.diagnostic()
.struct_span_err(sp, &format!("`..` can only be used once per {} pattern", ctx))
.span_label(sp, &format!("can only be used once per {} pattern", ctx))
.span_label(prev_sp, "previously used here")
.emit();
}
/// Used to ban the `..` pattern in places it shouldn't be semantically.
fn ban_illegal_rest_pat(&self, sp: Span) -> hir::PatKind<'hir> {
self.diagnostic()
.struct_span_err(sp, "`..` patterns are not allowed here")
.note("only allowed in tuple, tuple struct, and slice patterns")
.emit();
// We're not in a list context so `..` can be reasonably treated
// as `_` because it should always be valid and roughly matches the
// intent of `..` (notice that the rest of a single slot is that slot).
hir::PatKind::Wild
}
fn lower_range_end(&mut self, e: &RangeEnd) -> hir::RangeEnd {
match *e {
RangeEnd::Included(_) => hir::RangeEnd::Included,
RangeEnd::Excluded => hir::RangeEnd::Excluded,
}
}
}

422
src/librustc_ast_lowering/path.rs Normal file
View file

@ -0,0 +1,422 @@
use super::{AnonymousLifetimeMode, ImplTraitContext, LoweringContext, ParamMode};
use super::{GenericArgsCtor, ParenthesizedGenericArgs};
use rustc::lint::builtin::{self, ELIDED_LIFETIMES_IN_PATHS};
use rustc::span_bug;
use rustc_error_codes::*;
use rustc_errors::{struct_span_err, Applicability};
use rustc_hir as hir;
use rustc_hir::def::{DefKind, PartialRes, Res};
use rustc_hir::def_id::DefId;
use rustc_hir::GenericArg;
use rustc_span::Span;
use syntax::ast::{self, *};
use log::debug;
use smallvec::smallvec;
impl<'a, 'hir> LoweringContext<'a, 'hir> {
crate fn lower_qpath(
&mut self,
id: NodeId,
qself: &Option<QSelf>,
p: &Path,
param_mode: ParamMode,
mut itctx: ImplTraitContext<'_, 'hir>,
) -> hir::QPath<'hir> {
let qself_position = qself.as_ref().map(|q| q.position);
let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx.reborrow()));
let partial_res =
self.resolver.get_partial_res(id).unwrap_or_else(|| PartialRes::new(Res::Err));
let proj_start = p.segments.len() - partial_res.unresolved_segments();
let path = self.arena.alloc(hir::Path {
res: self.lower_res(partial_res.base_res()),
segments: self.arena.alloc_from_iter(p.segments[..proj_start].iter().enumerate().map(
|(i, segment)| {
let param_mode = match (qself_position, param_mode) {
(Some(j), ParamMode::Optional) if i < j => {
// This segment is part of the trait path in a
// qualified path - one of `a`, `b` or `Trait`
// in `<X as a::b::Trait>::T::U::method`.
ParamMode::Explicit
}
_ => param_mode,
};
// Figure out if this is a type/trait segment,
// which may need lifetime elision performed.
let parent_def_id = |this: &mut Self, def_id: DefId| DefId {
krate: def_id.krate,
index: this.resolver.def_key(def_id).parent.expect("missing parent"),
};
let type_def_id = match partial_res.base_res() {
Res::Def(DefKind::AssocTy, def_id) if i + 2 == proj_start => {
Some(parent_def_id(self, def_id))
}
Res::Def(DefKind::Variant, def_id) if i + 1 == proj_start => {
Some(parent_def_id(self, def_id))
}
Res::Def(DefKind::Struct, def_id)
| Res::Def(DefKind::Union, def_id)
| Res::Def(DefKind::Enum, def_id)
| Res::Def(DefKind::TyAlias, def_id)
| Res::Def(DefKind::Trait, def_id)
if i + 1 == proj_start =>
{
Some(def_id)
}
_ => None,
};
let parenthesized_generic_args = match partial_res.base_res() {
// `a::b::Trait(Args)`
Res::Def(DefKind::Trait, _) if i + 1 == proj_start => {
ParenthesizedGenericArgs::Ok
}
// `a::b::Trait(Args)::TraitItem`
Res::Def(DefKind::Method, _)
| Res::Def(DefKind::AssocConst, _)
| Res::Def(DefKind::AssocTy, _)
if i + 2 == proj_start =>
{
ParenthesizedGenericArgs::Ok
}
// Avoid duplicated errors.
Res::Err => ParenthesizedGenericArgs::Ok,
// An error
_ => ParenthesizedGenericArgs::Err,
};
let num_lifetimes = type_def_id.map_or(0, |def_id| {
if let Some(&n) = self.type_def_lifetime_params.get(&def_id) {
return n;
}
assert!(!def_id.is_local());
let n = self.resolver.item_generics_num_lifetimes(def_id, self.sess);
self.type_def_lifetime_params.insert(def_id, n);
n
});
self.lower_path_segment(
p.span,
segment,
param_mode,
num_lifetimes,
parenthesized_generic_args,
itctx.reborrow(),
None,
)
},
)),
span: p.span,
});
// Simple case, either no projections, or only fully-qualified.
// E.g., `std::mem::size_of` or `<I as Iterator>::Item`.
if partial_res.unresolved_segments() == 0 {
return hir::QPath::Resolved(qself, path);
}
// Create the innermost type that we're projecting from.
let mut ty = if path.segments.is_empty() {
// If the base path is empty that means there exists a
// syntactical `Self`, e.g., `&i32` in `<&i32>::clone`.
qself.expect("missing QSelf for <T>::...")
} else {
// Otherwise, the base path is an implicit `Self` type path,
// e.g., `Vec` in `Vec::new` or `<I as Iterator>::Item` in
// `<I as Iterator>::Item::default`.
let new_id = self.next_id();
self.arena.alloc(self.ty_path(new_id, p.span, hir::QPath::Resolved(qself, path)))
};
// Anything after the base path are associated "extensions",
// out of which all but the last one are associated types,
// e.g., for `std::vec::Vec::<T>::IntoIter::Item::clone`:
// * base path is `std::vec::Vec<T>`
// * "extensions" are `IntoIter`, `Item` and `clone`
// * type nodes are:
// 1. `std::vec::Vec<T>` (created above)
// 2. `<std::vec::Vec<T>>::IntoIter`
// 3. `<<std::vec::Vec<T>>::IntoIter>::Item`
// * final path is `<<<std::vec::Vec<T>>::IntoIter>::Item>::clone`
for (i, segment) in p.segments.iter().enumerate().skip(proj_start) {
let segment = self.arena.alloc(self.lower_path_segment(
p.span,
segment,
param_mode,
0,
ParenthesizedGenericArgs::Err,
itctx.reborrow(),
None,
));
let qpath = hir::QPath::TypeRelative(ty, segment);
// It's finished, return the extension of the right node type.
if i == p.segments.len() - 1 {
return qpath;
}
// Wrap the associated extension in another type node.
let new_id = self.next_id();
ty = self.arena.alloc(self.ty_path(new_id, p.span, qpath));
}
// We should've returned in the for loop above.
span_bug!(
p.span,
"lower_qpath: no final extension segment in {}..{}",
proj_start,
p.segments.len()
)
}
crate fn lower_path_extra(
&mut self,
res: Res,
p: &Path,
param_mode: ParamMode,
explicit_owner: Option<NodeId>,
) -> &'hir hir::Path<'hir> {
self.arena.alloc(hir::Path {
res,
segments: self.arena.alloc_from_iter(p.segments.iter().map(|segment| {
self.lower_path_segment(
p.span,
segment,
param_mode,
0,
ParenthesizedGenericArgs::Err,
ImplTraitContext::disallowed(),
explicit_owner,
)
})),
span: p.span,
})
}
crate fn lower_path(
&mut self,
id: NodeId,
p: &Path,
param_mode: ParamMode,
) -> &'hir hir::Path<'hir> {
let res = self.expect_full_res(id);
let res = self.lower_res(res);
self.lower_path_extra(res, p, param_mode, None)
}
crate fn lower_path_segment(
&mut self,
path_span: Span,
segment: &PathSegment,
param_mode: ParamMode,
expected_lifetimes: usize,
parenthesized_generic_args: ParenthesizedGenericArgs,
itctx: ImplTraitContext<'_, 'hir>,
explicit_owner: Option<NodeId>,
) -> hir::PathSegment<'hir> {
let (mut generic_args, infer_args) = if let Some(ref generic_args) = segment.args {
let msg = "parenthesized type parameters may only be used with a `Fn` trait";
match **generic_args {
GenericArgs::AngleBracketed(ref data) => {
self.lower_angle_bracketed_parameter_data(data, param_mode, itctx)
}
GenericArgs::Parenthesized(ref data) => match parenthesized_generic_args {
ParenthesizedGenericArgs::Ok => self.lower_parenthesized_parameter_data(data),
ParenthesizedGenericArgs::Err => {
let mut err = struct_span_err!(self.sess, data.span, E0214, "{}", msg);
err.span_label(data.span, "only `Fn` traits may use parentheses");
if let Ok(snippet) = self.sess.source_map().span_to_snippet(data.span) {
// Do not suggest going from `Trait()` to `Trait<>`
if data.inputs.len() > 0 {
if let Some(split) = snippet.find('(') {
let trait_name = &snippet[0..split];
let args = &snippet[split + 1..snippet.len() - 1];
err.span_suggestion(
data.span,
"use angle brackets instead",
format!("{}<{}>", trait_name, args),
Applicability::MaybeIncorrect,
);
}
}
};
err.emit();
(
self.lower_angle_bracketed_parameter_data(
&data.as_angle_bracketed_args(),
param_mode,
itctx,
)
.0,
false,
)
}
},
}
} else {
self.lower_angle_bracketed_parameter_data(&Default::default(), param_mode, itctx)
};
let has_lifetimes = generic_args.args.iter().any(|arg| match arg {
GenericArg::Lifetime(_) => true,
_ => false,
});
let first_generic_span = generic_args
.args
.iter()
.map(|a| a.span())
.chain(generic_args.bindings.iter().map(|b| b.span))
.next();
if !generic_args.parenthesized && !has_lifetimes {
generic_args.args = self
.elided_path_lifetimes(path_span, expected_lifetimes)
.map(|lt| GenericArg::Lifetime(lt))
.chain(generic_args.args.into_iter())
.collect();
if expected_lifetimes > 0 && param_mode == ParamMode::Explicit {
let anon_lt_suggestion = vec!["'_"; expected_lifetimes].join(", ");
let no_non_lt_args = generic_args.args.len() == expected_lifetimes;
let no_bindings = generic_args.bindings.is_empty();
let (incl_angl_brckt, insertion_sp, suggestion) = if no_non_lt_args && no_bindings {
// If there are no (non-implicit) generic args or associated type
// bindings, our suggestion includes the angle brackets.
(true, path_span.shrink_to_hi(), format!("<{}>", anon_lt_suggestion))
} else {
// Otherwise (sorry, this is kind of gross) we need to infer the
// place to splice in the `'_, ` from the generics that do exist.
let first_generic_span = first_generic_span
.expect("already checked that non-lifetime args or bindings exist");
(false, first_generic_span.shrink_to_lo(), format!("{}, ", anon_lt_suggestion))
};
match self.anonymous_lifetime_mode {
// In create-parameter mode we error here because we don't want to support
// deprecated impl elision in new features like impl elision and `async fn`,
// both of which work using the `CreateParameter` mode:
//
// impl Foo for std::cell::Ref<u32> // note lack of '_
// async fn foo(_: std::cell::Ref<u32>) { ... }
AnonymousLifetimeMode::CreateParameter => {
let mut err = struct_span_err!(
self.sess,
path_span,
E0726,
"implicit elided lifetime not allowed here"
);
crate::lint::builtin::add_elided_lifetime_in_path_suggestion(
&self.sess,
&mut err,
expected_lifetimes,
path_span,
incl_angl_brckt,
insertion_sp,
suggestion,
);
err.emit();
}
AnonymousLifetimeMode::PassThrough | AnonymousLifetimeMode::ReportError => {
self.resolver.lint_buffer().buffer_lint_with_diagnostic(
ELIDED_LIFETIMES_IN_PATHS,
CRATE_NODE_ID,
path_span,
"hidden lifetime parameters in types are deprecated",
builtin::BuiltinLintDiagnostics::ElidedLifetimesInPaths(
expected_lifetimes,
path_span,
incl_angl_brckt,
insertion_sp,
suggestion,
),
);
}
}
}
}
let res = self.expect_full_res(segment.id);
let id = if let Some(owner) = explicit_owner {
self.lower_node_id_with_owner(segment.id, owner)
} else {
self.lower_node_id(segment.id)
};
debug!(
"lower_path_segment: ident={:?} original-id={:?} new-id={:?}",
segment.ident, segment.id, id,
);
hir::PathSegment {
ident: segment.ident,
hir_id: Some(id),
res: Some(self.lower_res(res)),
infer_args,
args: if generic_args.is_empty() {
None
} else {
Some(self.arena.alloc(generic_args.into_generic_args(self.arena)))
},
}
}
fn lower_angle_bracketed_parameter_data(
&mut self,
data: &AngleBracketedArgs,
param_mode: ParamMode,
mut itctx: ImplTraitContext<'_, 'hir>,
) -> (GenericArgsCtor<'hir>, bool) {
let &AngleBracketedArgs { ref args, ref constraints, .. } = data;
let has_non_lt_args = args.iter().any(|arg| match arg {
ast::GenericArg::Lifetime(_) => false,
ast::GenericArg::Type(_) => true,
ast::GenericArg::Const(_) => true,
});
(
GenericArgsCtor {
args: args.iter().map(|a| self.lower_generic_arg(a, itctx.reborrow())).collect(),
bindings: self.arena.alloc_from_iter(
constraints.iter().map(|b| self.lower_assoc_ty_constraint(b, itctx.reborrow())),
),
parenthesized: false,
},
!has_non_lt_args && param_mode == ParamMode::Optional,
)
}
fn lower_parenthesized_parameter_data(
&mut self,
data: &ParenthesizedArgs,
) -> (GenericArgsCtor<'hir>, bool) {
// Switch to `PassThrough` mode for anonymous lifetimes; this
// means that we permit things like `&Ref<T>`, where `Ref` has
// a hidden lifetime parameter. This is needed for backwards
// compatibility, even in contexts like an impl header where
// we generally don't permit such things (see #51008).
self.with_anonymous_lifetime_mode(AnonymousLifetimeMode::PassThrough, |this| {
let &ParenthesizedArgs { ref inputs, ref output, span } = data;
let inputs = this.arena.alloc_from_iter(
inputs.iter().map(|ty| this.lower_ty_direct(ty, ImplTraitContext::disallowed())),
);
let output_ty = match output {
FunctionRetTy::Ty(ty) => this.lower_ty(&ty, ImplTraitContext::disallowed()),
FunctionRetTy::Default(_) => this.arena.alloc(this.ty_tup(span, &[])),
};
let args = smallvec![GenericArg::Type(this.ty_tup(span, inputs))];
let binding = this.output_ty_binding(output_ty.span, output_ty);
(
GenericArgsCtor { args, bindings: arena_vec![this; binding], parenthesized: true },
false,
)
})
}
/// An associated type binding `Output = $ty`.
crate fn output_ty_binding(
&mut self,
span: Span,
ty: &'hir hir::Ty<'hir>,
) -> hir::TypeBinding<'hir> {
let ident = Ident::with_dummy_span(hir::FN_OUTPUT_NAME);
let kind = hir::TypeBindingKind::Equality { ty };
hir::TypeBinding { hir_id: self.next_id(), span, ident, kind }
}
}

0
src/librustc/util/captures.rs → src/librustc_data_structures/captures.rs
View file

1
src/librustc_data_structures/lib.rs
View file

@ -67,6 +67,7 @@ macro_rules! unlikely {
pub mod base_n;
pub mod binary_search_util;
pub mod box_region;
pub mod captures;
pub mod const_cstr;
pub mod flock;
pub mod fx;

3
src/librustc_hir/hir.rs
View file

@ -1875,6 +1875,9 @@ pub enum ImplItemKind<'hir> {
OpaqueTy(GenericBounds<'hir>),
}
// The name of the associated type for `Fn` return types.
pub const FN_OUTPUT_NAME: Symbol = sym::Output;
/// Bind a type to an associated type (i.e., `A = Foo`).
///
/// Bindings like `A: Debug` are represented as a special type `A =

3
src/librustc_metadata/creader.rs
View file

@ -12,8 +12,7 @@ use rustc::session::{CrateDisambiguator, Session};
use rustc::ty::TyCtxt;
use rustc_data_structures::svh::Svh;
use rustc_data_structures::sync::Lrc;
use rustc_hir::def_id::CrateNum;
use rustc_hir::def_id::LOCAL_CRATE;
use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
use rustc_index::vec::IndexVec;
use rustc_target::spec::{PanicStrategy, TargetTriple};

2
src/librustc_metadata/rmeta/decoder.rs
View file

@ -16,8 +16,8 @@ use rustc::mir::{self, interpret, BodyAndCache, Promoted};
use rustc::session::Session;
use rustc::ty::codec::TyDecoder;
use rustc::ty::{self, Ty, TyCtxt};
use rustc::util::captures::Captures;
use rustc::util::common::record_time;
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::svh::Svh;

8
src/librustc_metadata/rmeta/decoder/cstore_impl.rs
View file

@ -478,6 +478,10 @@ impl CStore {
pub fn crate_source_untracked(&self, cnum: CrateNum) -> CrateSource {
self.get_crate_data(cnum).source.clone()
}
pub fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
self.get_crate_data(def_id.krate).get_generics(def_id.index, sess).own_counts().lifetimes
}
}
impl CrateStore for CStore {
@ -485,10 +489,6 @@ impl CrateStore for CStore {
self
}
fn item_generics_cloned_untracked(&self, def: DefId, sess: &Session) -> ty::Generics {
self.get_crate_data(def.krate).get_generics(def.index, sess)
}
fn crate_name_untracked(&self, cnum: CrateNum) -> Symbol {
self.get_crate_data(cnum).root.name
}

2
src/librustc_mir/hair/pattern/_match.rs
View file

@ -229,6 +229,7 @@ use self::SliceKind::*;
use self::Usefulness::*;
use self::WitnessPreference::*;
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fx::FxHashMap;
use rustc_index::vec::Idx;
@ -243,7 +244,6 @@ use rustc_hir::{HirId, RangeEnd};
use rustc::lint;
use rustc::mir::interpret::{truncate, AllocId, ConstValue, Pointer, Scalar};
use rustc::mir::Field;
use rustc::util::captures::Captures;
use rustc::util::common::ErrorReported;
use rustc_span::{Span, DUMMY_SP};

10
src/librustc_resolve/lib.rs
View file

@ -22,7 +22,7 @@ use Determinacy::*;
use errors::{struct_span_err, Applicability, DiagnosticBuilder};
use rustc::hir::exports::ExportMap;
use rustc::hir::map::Definitions;
use rustc::hir::map::{DefKey, Definitions};
use rustc::lint;
use rustc::middle::cstore::{CrateStore, MetadataLoaderDyn};
use rustc::session::Session;
@ -1027,8 +1027,12 @@ impl<'a, 'b> DefIdTree for &'a Resolver<'b> {
/// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
/// the resolver is no longer needed as all the relevant information is inline.
impl rustc_ast_lowering::Resolver for Resolver<'_> {
fn cstore(&self) -> &dyn CrateStore {
self.cstore()
fn def_key(&mut self, id: DefId) -> DefKey {
if id.is_local() { self.definitions().def_key(id.index) } else { self.cstore().def_key(id) }
}
fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
self.cstore().item_generics_num_lifetimes(def_id, sess)
}
fn resolve_str_path(

2
src/librustc_typeck/check/mod.rs
View file

@ -114,6 +114,7 @@ use rustc::ty::{
self, AdtKind, CanonicalUserType, Const, GenericParamDefKind, RegionKind, ToPolyTraitRef,
ToPredicate, Ty, TyCtxt, UserType,
};
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_hir as hir;
use rustc_hir::def::{CtorOf, DefKind, Res};
@ -146,7 +147,6 @@ use crate::lint;
use crate::require_c_abi_if_c_variadic;
use crate::session::config::EntryFnType;
use crate::session::Session;
use crate::util::captures::Captures;
use crate::util::common::{indenter, ErrorReported};
use crate::TypeAndSubsts;

2
src/librustc_typeck/collect.rs
View file

@ -32,7 +32,7 @@ use rustc::ty::util::Discr;
use rustc::ty::util::IntTypeExt;
use rustc::ty::{self, AdtKind, Const, DefIdTree, ToPolyTraitRef, Ty, TyCtxt};
use rustc::ty::{ReprOptions, ToPredicate};
use rustc::util::captures::Captures;
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir as hir;
use rustc_hir::def::{CtorKind, DefKind, Res};