mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-27 17:24:06 +00:00
rustc: Remove used_mut_nodes
from TyCtxt
This updates the borrowck query to return a result, and this result is then used to incrementally check for unused mutable nodes given sets of all the used mutable nodes. Closes #42384
This commit is contained in:
parent
af7de7b677
commit
4df1278c69
2
src/Cargo.lock
generated
2
src/Cargo.lock
generated
@ -1504,6 +1504,7 @@ dependencies = [
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"graphviz 0.0.0",
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"log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
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"rustc 0.0.0",
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"rustc_back 0.0.0",
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"rustc_errors 0.0.0",
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"rustc_mir 0.0.0",
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"syntax 0.0.0",
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@ -1611,7 +1612,6 @@ version = "0.0.0"
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dependencies = [
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"log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
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"rustc 0.0.0",
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"rustc_back 0.0.0",
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"rustc_const_eval 0.0.0",
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"syntax 0.0.0",
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"syntax_pos 0.0.0",
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@ -106,6 +106,7 @@ pub mod lint;
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pub mod middle {
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pub mod allocator;
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pub mod borrowck;
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pub mod expr_use_visitor;
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pub mod const_val;
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pub mod cstore;
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@ -222,6 +222,12 @@ declare_lint! {
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"unnecessary use of an `unsafe` block"
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}
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declare_lint! {
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pub UNUSED_MUT,
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Warn,
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"detect mut variables which don't need to be mutable"
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}
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/// Does nothing as a lint pass, but registers some `Lint`s
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/// which are used by other parts of the compiler.
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#[derive(Copy, Clone)]
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@ -263,7 +269,8 @@ impl LintPass for HardwiredLints {
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PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES,
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LATE_BOUND_LIFETIME_ARGUMENTS,
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DEPRECATED,
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UNUSED_UNSAFE
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UNUSED_UNSAFE,
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UNUSED_MUT
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)
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}
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}
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31
src/librustc/middle/borrowck.rs
Normal file
31
src/librustc/middle/borrowck.rs
Normal file
@ -0,0 +1,31 @@
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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use ich::StableHashingContext;
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use hir::HirId;
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use util::nodemap::FxHashSet;
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use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
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StableHasherResult};
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pub struct BorrowCheckResult {
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pub used_mut_nodes: FxHashSet<HirId>,
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}
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impl<'gcx> HashStable<StableHashingContext<'gcx>> for BorrowCheckResult {
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fn hash_stable<W: StableHasherResult>(&self,
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hcx: &mut StableHashingContext<'gcx>,
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hasher: &mut StableHasher<W>) {
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let BorrowCheckResult {
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ref used_mut_nodes,
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} = *self;
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used_mut_nodes.hash_stable(hcx, hasher);
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}
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}
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@ -898,11 +898,6 @@ pub struct GlobalCtxt<'tcx> {
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pub inhabitedness_cache: RefCell<FxHashMap<Ty<'tcx>, DefIdForest>>,
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/// Set of nodes which mark locals as mutable which end up getting used at
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/// some point. Local variable definitions not in this set can be warned
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/// about.
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pub used_mut_nodes: RefCell<NodeSet>,
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/// Caches the results of trait selection. This cache is used
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/// for things that do not have to do with the parameters in scope.
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pub selection_cache: traits::SelectionCache<'tcx>,
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@ -1185,7 +1180,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
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rcache: RefCell::new(FxHashMap()),
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normalized_cache: RefCell::new(FxHashMap()),
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inhabitedness_cache: RefCell::new(FxHashMap()),
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used_mut_nodes: RefCell::new(NodeSet()),
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selection_cache: traits::SelectionCache::new(),
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evaluation_cache: traits::EvaluationCache::new(),
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rvalue_promotable_to_static: RefCell::new(NodeMap()),
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@ -15,6 +15,7 @@ use hir::def::{Def, Export};
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use hir::{self, TraitCandidate, ItemLocalId};
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use hir::svh::Svh;
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use lint;
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use middle::borrowck::BorrowCheckResult;
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use middle::const_val;
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use middle::cstore::{ExternCrate, LinkagePreference, NativeLibrary,
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ExternBodyNestedBodies};
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@ -183,7 +184,7 @@ define_maps! { <'tcx>
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[] fn coherent_trait: coherent_trait_dep_node((CrateNum, DefId)) -> (),
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[] fn borrowck: BorrowCheck(DefId) -> (),
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[] fn borrowck: BorrowCheck(DefId) -> Rc<BorrowCheckResult>,
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// FIXME: shouldn't this return a `Result<(), BorrowckErrors>` instead?
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[] fn mir_borrowck: MirBorrowCheck(DefId) -> (),
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@ -15,5 +15,6 @@ syntax = { path = "../libsyntax" }
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syntax_pos = { path = "../libsyntax_pos" }
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graphviz = { path = "../libgraphviz" }
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rustc = { path = "../librustc" }
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rustc_back = { path = "../librustc_back" }
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rustc_mir = { path = "../librustc_mir" }
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rustc_errors = { path = "../librustc_errors" }
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@ -770,7 +770,8 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
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let lp = opt_loan_path(&assignee_cmt).unwrap();
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self.move_data.each_assignment_of(assignment_id, &lp, |assign| {
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if assignee_cmt.mutbl.is_mutable() {
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self.tcx().used_mut_nodes.borrow_mut().insert(local_id);
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let hir_id = self.bccx.tcx.hir.node_to_hir_id(local_id);
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self.bccx.used_mut_nodes.borrow_mut().insert(hir_id);
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} else {
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self.bccx.report_reassigned_immutable_variable(
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assignment_span,
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@ -442,13 +442,13 @@ impl<'a, 'tcx> GatherLoanCtxt<'a, 'tcx> {
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wrapped_path = match current_path.kind {
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LpVar(local_id) => {
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if !through_borrow {
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self.tcx().used_mut_nodes.borrow_mut().insert(local_id);
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let hir_id = self.bccx.tcx.hir.node_to_hir_id(local_id);
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self.bccx.used_mut_nodes.borrow_mut().insert(hir_id);
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}
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None
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}
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LpUpvar(ty::UpvarId{ var_id, closure_expr_id: _ }) => {
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let local_id = self.tcx().hir.hir_to_node_id(var_id);
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self.tcx().used_mut_nodes.borrow_mut().insert(local_id);
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self.bccx.used_mut_nodes.borrow_mut().insert(var_id);
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None
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}
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LpExtend(ref base, mc::McInherited, LpDeref(pointer_kind)) |
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@ -20,6 +20,7 @@ pub use self::MovedValueUseKind::*;
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use self::InteriorKind::*;
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use rustc::hir::HirId;
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use rustc::hir::map as hir_map;
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use rustc::hir::map::blocks::FnLikeNode;
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use rustc::cfg;
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@ -27,6 +28,7 @@ use rustc::middle::dataflow::DataFlowContext;
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use rustc::middle::dataflow::BitwiseOperator;
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use rustc::middle::dataflow::DataFlowOperator;
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use rustc::middle::dataflow::KillFrom;
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use rustc::middle::borrowck::BorrowCheckResult;
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use rustc::hir::def_id::{DefId, DefIndex};
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use rustc::middle::expr_use_visitor as euv;
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use rustc::middle::mem_categorization as mc;
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@ -37,7 +39,9 @@ use rustc::middle::free_region::RegionRelations;
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use rustc::ty::{self, Ty, TyCtxt};
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use rustc::ty::maps::Providers;
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use rustc_mir::util::borrowck_errors::{BorrowckErrors, Origin};
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use rustc::util::nodemap::FxHashSet;
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use std::cell::RefCell;
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use std::fmt;
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use std::rc::Rc;
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use std::hash::{Hash, Hasher};
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@ -54,6 +58,8 @@ pub mod gather_loans;
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pub mod move_data;
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mod unused;
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#[derive(Clone, Copy)]
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pub struct LoanDataFlowOperator;
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@ -79,7 +85,9 @@ pub struct AnalysisData<'a, 'tcx: 'a> {
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pub move_data: move_data::FlowedMoveData<'a, 'tcx>,
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}
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fn borrowck<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, owner_def_id: DefId) {
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fn borrowck<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, owner_def_id: DefId)
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-> Rc<BorrowCheckResult>
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{
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debug!("borrowck(body_owner_def_id={:?})", owner_def_id);
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let owner_id = tcx.hir.as_local_node_id(owner_def_id).unwrap();
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@ -91,7 +99,9 @@ fn borrowck<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, owner_def_id: DefId) {
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// those things (notably the synthesized constructors from
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// tuple structs/variants) do not have an associated body
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// and do not need borrowchecking.
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return;
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return Rc::new(BorrowCheckResult {
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used_mut_nodes: FxHashSet(),
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})
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}
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_ => { }
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}
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@ -100,7 +110,14 @@ fn borrowck<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, owner_def_id: DefId) {
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let tables = tcx.typeck_tables_of(owner_def_id);
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let region_scope_tree = tcx.region_scope_tree(owner_def_id);
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let body = tcx.hir.body(body_id);
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let bccx = &mut BorrowckCtxt { tcx, tables, region_scope_tree, owner_def_id, body };
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let mut bccx = BorrowckCtxt {
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tcx,
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tables,
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region_scope_tree,
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owner_def_id,
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body,
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used_mut_nodes: RefCell::new(FxHashSet()),
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};
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// Eventually, borrowck will always read the MIR, but at the
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// moment we do not. So, for now, we always force MIR to be
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@ -118,14 +135,19 @@ fn borrowck<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, owner_def_id: DefId) {
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if let Some(AnalysisData { all_loans,
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loans: loan_dfcx,
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move_data: flowed_moves }) =
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build_borrowck_dataflow_data(bccx, false, body_id,
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build_borrowck_dataflow_data(&mut bccx, false, body_id,
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|bccx| {
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cfg = Some(cfg::CFG::new(bccx.tcx, &body));
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cfg.as_mut().unwrap()
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})
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{
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check_loans::check_loans(bccx, &loan_dfcx, &flowed_moves, &all_loans, body);
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check_loans::check_loans(&mut bccx, &loan_dfcx, &flowed_moves, &all_loans, body);
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}
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unused::check(&mut bccx, body);
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Rc::new(BorrowCheckResult {
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used_mut_nodes: bccx.used_mut_nodes.into_inner(),
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})
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}
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fn build_borrowck_dataflow_data<'a, 'c, 'tcx, F>(this: &mut BorrowckCtxt<'a, 'tcx>,
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@ -198,7 +220,14 @@ pub fn build_borrowck_dataflow_data_for_fn<'a, 'tcx>(
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let tables = tcx.typeck_tables_of(owner_def_id);
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let region_scope_tree = tcx.region_scope_tree(owner_def_id);
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let body = tcx.hir.body(body_id);
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let mut bccx = BorrowckCtxt { tcx, tables, region_scope_tree, owner_def_id, body };
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let mut bccx = BorrowckCtxt {
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tcx,
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tables,
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region_scope_tree,
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owner_def_id,
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body,
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used_mut_nodes: RefCell::new(FxHashSet()),
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};
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let dataflow_data = build_borrowck_dataflow_data(&mut bccx, true, body_id, |_| cfg);
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(bccx, dataflow_data.unwrap())
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@ -219,6 +248,8 @@ pub struct BorrowckCtxt<'a, 'tcx: 'a> {
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owner_def_id: DefId,
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body: &'tcx hir::Body,
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used_mut_nodes: RefCell<FxHashSet<HirId>>,
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}
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impl<'b, 'tcx: 'b> BorrowckErrors for BorrowckCtxt<'b, 'tcx> {
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118
src/librustc_borrowck/borrowck/unused.rs
Normal file
118
src/librustc_borrowck/borrowck/unused.rs
Normal file
@ -0,0 +1,118 @@
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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use rustc::hir::intravisit::{Visitor, NestedVisitorMap};
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use rustc::hir::{self, HirId};
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use rustc::lint::builtin::UNUSED_MUT;
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use rustc::ty;
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use rustc::util::nodemap::{FxHashMap, FxHashSet};
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use rustc_back::slice;
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use syntax::ptr::P;
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use borrowck::BorrowckCtxt;
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pub fn check<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>, body: &'tcx hir::Body) {
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let mut used_mut = bccx.used_mut_nodes.borrow().clone();
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UsedMutFinder {
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bccx,
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set: &mut used_mut,
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}.visit_expr(&body.value);
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let mut cx = UnusedMutCx { bccx, used_mut };
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for arg in body.arguments.iter() {
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cx.check_unused_mut_pat(slice::ref_slice(&arg.pat));
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}
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cx.visit_expr(&body.value);
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}
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struct UsedMutFinder<'a, 'tcx: 'a> {
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bccx: &'a BorrowckCtxt<'a, 'tcx>,
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set: &'a mut FxHashSet<HirId>,
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}
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struct UnusedMutCx<'a, 'tcx: 'a> {
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bccx: &'a BorrowckCtxt<'a, 'tcx>,
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used_mut: FxHashSet<HirId>,
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}
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impl<'a, 'tcx> UnusedMutCx<'a, 'tcx> {
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fn check_unused_mut_pat(&self, pats: &[P<hir::Pat>]) {
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let tcx = self.bccx.tcx;
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let mut mutables = FxHashMap();
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for p in pats {
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p.each_binding(|_, id, span, path1| {
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let name = path1.node;
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// Skip anything that looks like `_foo`
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if name.as_str().starts_with("_") {
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return
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}
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// Skip anything that looks like `&foo` or `&mut foo`, only look
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// for by-value bindings
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let hir_id = tcx.hir.node_to_hir_id(id);
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let bm = match self.bccx.tables.pat_binding_modes().get(hir_id) {
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Some(&bm) => bm,
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None => span_bug!(span, "missing binding mode"),
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};
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match bm {
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ty::BindByValue(hir::MutMutable) => {}
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_ => return,
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}
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mutables.entry(name).or_insert(Vec::new()).push((id, hir_id, span));
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});
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}
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for (_name, ids) in mutables {
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// If any id for this name was used mutably then consider them all
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// ok, so move on to the next
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if ids.iter().any(|&(_, ref id, _)| self.used_mut.contains(id)) {
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continue
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}
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let mut_span = tcx.sess.codemap().span_until_char(ids[0].2, ' ');
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// Ok, every name wasn't used mutably, so issue a warning that this
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// didn't need to be mutable.
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tcx.struct_span_lint_node(UNUSED_MUT,
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ids[0].0,
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ids[0].2,
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"variable does not need to be mutable")
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.span_suggestion_short(mut_span, "remove this `mut`", "".to_owned())
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.emit();
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}
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}
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}
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impl<'a, 'tcx> Visitor<'tcx> for UnusedMutCx<'a, 'tcx> {
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fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
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NestedVisitorMap::OnlyBodies(&self.bccx.tcx.hir)
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}
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fn visit_arm(&mut self, arm: &hir::Arm) {
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self.check_unused_mut_pat(&arm.pats)
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}
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fn visit_local(&mut self, local: &hir::Local) {
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self.check_unused_mut_pat(slice::ref_slice(&local.pat));
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}
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}
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impl<'a, 'tcx> Visitor<'tcx> for UsedMutFinder<'a, 'tcx> {
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fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
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NestedVisitorMap::OnlyBodies(&self.bccx.tcx.hir)
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}
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fn visit_nested_body(&mut self, id: hir::BodyId) {
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let def_id = self.bccx.tcx.hir.body_owner_def_id(id);
|
||||
self.set.extend(self.bccx.tcx.borrowck(def_id).used_mut_nodes.iter().cloned());
|
||||
self.visit_body(self.bccx.tcx.hir.body(id));
|
||||
}
|
||||
}
|
@ -22,6 +22,7 @@
|
||||
#[macro_use] extern crate syntax;
|
||||
extern crate syntax_pos;
|
||||
extern crate rustc_errors as errors;
|
||||
extern crate rustc_back;
|
||||
|
||||
// for "clarity", rename the graphviz crate to dot; graphviz within `borrowck`
|
||||
// refers to the borrowck-specific graphviz adapter traits.
|
||||
|
@ -12,7 +12,6 @@ test = false
|
||||
[dependencies]
|
||||
log = "0.3"
|
||||
rustc = { path = "../librustc" }
|
||||
rustc_back = { path = "../librustc_back" }
|
||||
rustc_const_eval = { path = "../librustc_const_eval" }
|
||||
syntax = { path = "../libsyntax" }
|
||||
syntax_pos = { path = "../libsyntax_pos" }
|
||||
|
@ -38,7 +38,6 @@ extern crate syntax;
|
||||
extern crate rustc;
|
||||
#[macro_use]
|
||||
extern crate log;
|
||||
extern crate rustc_back;
|
||||
extern crate rustc_const_eval;
|
||||
extern crate syntax_pos;
|
||||
|
||||
@ -129,7 +128,6 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
|
||||
NonUpperCaseGlobals,
|
||||
NonShorthandFieldPatterns,
|
||||
UnsafeCode,
|
||||
UnusedMut,
|
||||
UnusedAllocation,
|
||||
MissingCopyImplementations,
|
||||
UnstableFeatures,
|
||||
|
@ -11,105 +11,18 @@
|
||||
use rustc::hir::def_id::DefId;
|
||||
use rustc::ty;
|
||||
use rustc::ty::adjustment;
|
||||
use util::nodemap::FxHashMap;
|
||||
use lint::{LateContext, EarlyContext, LintContext, LintArray};
|
||||
use lint::{LintPass, EarlyLintPass, LateLintPass};
|
||||
|
||||
use std::collections::hash_map::Entry::{Occupied, Vacant};
|
||||
|
||||
use syntax::ast;
|
||||
use syntax::attr;
|
||||
use syntax::feature_gate::{BUILTIN_ATTRIBUTES, AttributeType};
|
||||
use syntax::symbol::keywords;
|
||||
use syntax::ptr::P;
|
||||
use syntax::print::pprust;
|
||||
use syntax::symbol::keywords;
|
||||
use syntax::util::parser;
|
||||
use syntax_pos::Span;
|
||||
|
||||
use rustc_back::slice;
|
||||
use rustc::hir;
|
||||
use rustc::hir::intravisit::FnKind;
|
||||
|
||||
declare_lint! {
|
||||
pub UNUSED_MUT,
|
||||
Warn,
|
||||
"detect mut variables which don't need to be mutable"
|
||||
}
|
||||
|
||||
#[derive(Copy, Clone)]
|
||||
pub struct UnusedMut;
|
||||
|
||||
impl UnusedMut {
|
||||
fn check_unused_mut_pat(&self, cx: &LateContext, pats: &[P<hir::Pat>]) {
|
||||
// collect all mutable pattern and group their NodeIDs by their Identifier to
|
||||
// avoid false warnings in match arms with multiple patterns
|
||||
|
||||
let mut mutables = FxHashMap();
|
||||
for p in pats {
|
||||
p.each_binding(|_, id, span, path1| {
|
||||
let hir_id = cx.tcx.hir.node_to_hir_id(id);
|
||||
let bm = match cx.tables.pat_binding_modes().get(hir_id) {
|
||||
Some(&bm) => bm,
|
||||
None => span_bug!(span, "missing binding mode"),
|
||||
};
|
||||
let name = path1.node;
|
||||
if let ty::BindByValue(hir::MutMutable) = bm {
|
||||
if !name.as_str().starts_with("_") {
|
||||
match mutables.entry(name) {
|
||||
Vacant(entry) => {
|
||||
entry.insert(vec![id]);
|
||||
}
|
||||
Occupied(mut entry) => {
|
||||
entry.get_mut().push(id);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
});
|
||||
}
|
||||
|
||||
let used_mutables = cx.tcx.used_mut_nodes.borrow();
|
||||
for (_, v) in &mutables {
|
||||
if !v.iter().any(|e| used_mutables.contains(e)) {
|
||||
let binding_span = cx.tcx.hir.span(v[0]);
|
||||
let mut_span = cx.tcx.sess.codemap().span_until_char(binding_span, ' ');
|
||||
let mut err = cx.struct_span_lint(UNUSED_MUT,
|
||||
binding_span,
|
||||
"variable does not need to be mutable");
|
||||
err.span_suggestion_short(mut_span, "remove this `mut`", "".to_owned());
|
||||
err.emit();
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl LintPass for UnusedMut {
|
||||
fn get_lints(&self) -> LintArray {
|
||||
lint_array!(UNUSED_MUT)
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedMut {
|
||||
fn check_arm(&mut self, cx: &LateContext, a: &hir::Arm) {
|
||||
self.check_unused_mut_pat(cx, &a.pats)
|
||||
}
|
||||
|
||||
fn check_local(&mut self, cx: &LateContext, l: &hir::Local) {
|
||||
self.check_unused_mut_pat(cx, slice::ref_slice(&l.pat));
|
||||
}
|
||||
|
||||
fn check_fn(&mut self,
|
||||
cx: &LateContext,
|
||||
_: FnKind,
|
||||
_: &hir::FnDecl,
|
||||
body: &hir::Body,
|
||||
_: Span,
|
||||
_: ast::NodeId) {
|
||||
for a in &body.arguments {
|
||||
self.check_unused_mut_pat(cx, slice::ref_slice(&a.pat));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
declare_lint! {
|
||||
pub UNUSED_MUST_USE,
|
||||
|
@ -14,6 +14,20 @@ warning: use of deprecated attribute `no_debug`: the `#[no_debug]` attribute was
|
||||
|
|
||||
= note: #[warn(deprecated)] on by default
|
||||
|
||||
warning: variable does not need to be mutable
|
||||
--> $DIR/suggestions.rs:17:13
|
||||
|
|
||||
17 | let mut a = (1); // should suggest no `mut`, no parens
|
||||
| ---^^
|
||||
| |
|
||||
| help: remove this `mut`
|
||||
|
|
||||
note: lint level defined here
|
||||
--> $DIR/suggestions.rs:11:9
|
||||
|
|
||||
11 | #![warn(unused_mut)] // UI tests pass `-A unused`—see Issue #43896
|
||||
| ^^^^^^^^^^
|
||||
|
||||
warning: denote infinite loops with `loop { ... }`
|
||||
--> $DIR/suggestions.rs:16:5
|
||||
|
|
||||
@ -29,17 +43,3 @@ warning: denote infinite loops with `loop { ... }`
|
||||
|
|
||||
= note: #[warn(while_true)] on by default
|
||||
|
||||
warning: variable does not need to be mutable
|
||||
--> $DIR/suggestions.rs:17:13
|
||||
|
|
||||
17 | let mut a = (1); // should suggest no `mut`, no parens
|
||||
| ---^^
|
||||
| |
|
||||
| help: remove this `mut`
|
||||
|
|
||||
note: lint level defined here
|
||||
--> $DIR/suggestions.rs:11:9
|
||||
|
|
||||
11 | #![warn(unused_mut)] // UI tests pass `-A unused`—see Issue #43896
|
||||
| ^^^^^^^^^^
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user