diff options
Diffstat (limited to 'clippy_utils')
| -rw-r--r-- | clippy_utils/src/lib.rs | 270 |
1 files changed, 264 insertions, 6 deletions
diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs index cf33076d356..8429192437c 100644 --- a/clippy_utils/src/lib.rs +++ b/clippy_utils/src/lib.rs @@ -89,15 +89,14 @@ use rustc_hir::intravisit::{walk_expr, FnKind, Visitor}; use rustc_hir::LangItem::{OptionNone, OptionSome, ResultErr, ResultOk}; use rustc_hir::{ self as hir, def, Arm, ArrayLen, BindingAnnotation, Block, BlockCheckMode, Body, Closure, Destination, Expr, - ExprKind, FnDecl, HirId, Impl, ImplItem, ImplItemKind, ImplItemRef, IsAsync, Item, ItemKind, LangItem, Local, - MatchSource, Mutability, Node, OwnerId, Param, Pat, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, - TraitItem, TraitItemRef, TraitRef, TyKind, UnOp, + ExprField, ExprKind, FnDecl, FnRetTy, GenericArgs, HirId, Impl, ImplItem, ImplItemKind, ImplItemRef, IsAsync, Item, + ItemKind, LangItem, Local, MatchSource, Mutability, Node, OwnerId, Param, Pat, PatKind, Path, PathSegment, PrimTy, + QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitItemRef, TraitRef, TyKind, UnOp, }; use rustc_lexer::{tokenize, TokenKind}; use rustc_lint::{LateContext, Level, Lint, LintContext}; use rustc_middle::hir::place::PlaceBase; use rustc_middle::mir::ConstantKind; -use rustc_middle::ty as rustc_ty; use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow}; use rustc_middle::ty::binding::BindingMode; use rustc_middle::ty::fast_reject::SimplifiedType::{ @@ -106,7 +105,8 @@ use rustc_middle::ty::fast_reject::SimplifiedType::{ }; use rustc_middle::ty::layout::IntegerExt; use rustc_middle::ty::{ - BorrowKind, ClosureKind, FloatTy, IntTy, Ty, TyCtxt, TypeAndMut, TypeVisitableExt, UintTy, UpvarCapture, + self as rustc_ty, Binder, BorrowKind, ClosureKind, FloatTy, IntTy, ParamEnv, ParamEnvAnd, Ty, TyCtxt, TypeAndMut, + TypeVisitableExt, UintTy, UpvarCapture, }; use rustc_span::hygiene::{ExpnKind, MacroKind}; use rustc_span::source_map::SourceMap; @@ -116,7 +116,10 @@ use rustc_target::abi::Integer; use crate::consts::{constant, miri_to_const, Constant}; use crate::higher::Range; -use crate::ty::{can_partially_move_ty, expr_sig, is_copy, is_recursively_primitive_type, ty_is_fn_once_param}; +use crate::ty::{ + adt_and_variant_of_res, can_partially_move_ty, expr_sig, is_copy, is_recursively_primitive_type, + ty_is_fn_once_param, +}; use crate::visitors::for_each_expr; use rustc_middle::hir::nested_filter; @@ -2502,6 +2505,261 @@ pub fn walk_to_expr_usage<'tcx, T>( None } +/// A type definition as it would be viewed from within a function. +#[derive(Clone, Copy)] +pub enum DefinedTy<'tcx> { + // Used for locals and closures defined within the function. + Hir(&'tcx hir::Ty<'tcx>), + /// Used for function signatures, and constant and static values. This includes the `ParamEnv` + /// from the definition site. + Mir(ParamEnvAnd<'tcx, Binder<'tcx, Ty<'tcx>>>), +} + +/// The context an expressions value is used in. +pub struct ExprUseCtxt<'tcx> { + /// The parent node which consumes the value. + pub node: ExprUseNode<'tcx>, + /// Any adjustments applied to the type. + pub adjustments: &'tcx [Adjustment<'tcx>], + /// Whether or not the type must unify with another code path. + pub is_ty_unified: bool, + /// Whether or not the value will be moved before it's used. + pub moved_before_use: bool, +} + +/// The node which consumes a value. +pub enum ExprUseNode<'tcx> { + /// Assignment to, or initializer for, a local + Local(&'tcx Local<'tcx>), + /// Initializer for a const or static item. + ConstStatic(OwnerId), + /// Implicit or explicit return from a function. + Return(OwnerId), + /// Initialization of a struct field. + Field(&'tcx ExprField<'tcx>), + /// An argument to a function. + FnArg(&'tcx Expr<'tcx>, usize), + /// An argument to a method. + MethodArg(HirId, Option<&'tcx GenericArgs<'tcx>>, usize), + /// The callee of a function call. + Callee, + /// Access of a field. + FieldAccess(Ident), +} +impl<'tcx> ExprUseNode<'tcx> { + /// Checks if the value is returned from the function. + pub fn is_return(&self) -> bool { + matches!(self, Self::Return(_)) + } + + /// Checks if the value is used as a method call receiver. + pub fn is_recv(&self) -> bool { + matches!(self, Self::MethodArg(_, _, 0)) + } + + /// Gets the needed type as it's defined without any type inference. + pub fn defined_ty(&self, cx: &LateContext<'tcx>) -> Option<DefinedTy<'tcx>> { + match *self { + Self::Local(Local { ty: Some(ty), .. }) => Some(DefinedTy::Hir(ty)), + Self::ConstStatic(id) => Some(DefinedTy::Mir( + cx.param_env.and(Binder::dummy(cx.tcx.type_of(id).subst_identity())), + )), + Self::Return(id) => { + let hir_id = cx.tcx.hir().local_def_id_to_hir_id(id.def_id); + if let Some(Node::Expr(Expr { + kind: ExprKind::Closure(c), + .. + })) = cx.tcx.hir().find(hir_id) + { + match c.fn_decl.output { + FnRetTy::DefaultReturn(_) => None, + FnRetTy::Return(ty) => Some(DefinedTy::Hir(ty)), + } + } else { + Some(DefinedTy::Mir( + cx.param_env.and(cx.tcx.fn_sig(id).subst_identity().output()), + )) + } + }, + Self::Field(field) => match get_parent_expr_for_hir(cx, field.hir_id) { + Some(Expr { + hir_id, + kind: ExprKind::Struct(path, ..), + .. + }) => adt_and_variant_of_res(cx, cx.qpath_res(path, *hir_id)) + .and_then(|(adt, variant)| { + variant + .fields + .iter() + .find(|f| f.name == field.ident.name) + .map(|f| (adt, f)) + }) + .map(|(adt, field_def)| { + DefinedTy::Mir( + cx.tcx + .param_env(adt.did()) + .and(Binder::dummy(cx.tcx.type_of(field_def.did).subst_identity())), + ) + }), + _ => None, + }, + Self::FnArg(callee, i) => { + let sig = expr_sig(cx, callee)?; + let (hir_ty, ty) = sig.input_with_hir(i)?; + Some(match hir_ty { + Some(hir_ty) => DefinedTy::Hir(hir_ty), + None => DefinedTy::Mir( + sig.predicates_id() + .map_or(ParamEnv::empty(), |id| cx.tcx.param_env(id)) + .and(ty), + ), + }) + }, + Self::MethodArg(id, _, i) => { + let id = cx.typeck_results().type_dependent_def_id(id)?; + let sig = cx.tcx.fn_sig(id).skip_binder(); + Some(DefinedTy::Mir(cx.tcx.param_env(id).and(sig.input(i)))) + }, + Self::Local(_) | Self::FieldAccess(..) | Self::Callee => None, + } + } +} + +/// Gets the context an expression's value is used in. +#[expect(clippy::too_many_lines)] +pub fn expr_use_ctxt<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) -> Option<ExprUseCtxt<'tcx>> { + let mut adjustments = [].as_slice(); + let mut is_ty_unified = false; + let mut moved_before_use = false; + let ctxt = e.span.ctxt(); + walk_to_expr_usage(cx, e, &mut |parent, child_id| { + // LocalTableInContext returns the wrong lifetime, so go use `expr_adjustments` instead. + if adjustments.is_empty() && let Node::Expr(e) = cx.tcx.hir().get(child_id) { + adjustments = cx.typeck_results().expr_adjustments(e); + } + match parent { + Node::Local(l) if l.span.ctxt() == ctxt => Some(ExprUseCtxt { + node: ExprUseNode::Local(l), + adjustments, + is_ty_unified, + moved_before_use, + }), + Node::Item(&Item { + kind: ItemKind::Static(..) | ItemKind::Const(..), + owner_id, + span, + .. + }) + | Node::TraitItem(&TraitItem { + kind: TraitItemKind::Const(..), + owner_id, + span, + .. + }) + | Node::ImplItem(&ImplItem { + kind: ImplItemKind::Const(..), + owner_id, + span, + .. + }) if span.ctxt() == ctxt => Some(ExprUseCtxt { + node: ExprUseNode::ConstStatic(owner_id), + adjustments, + is_ty_unified, + moved_before_use, + }), + + Node::Item(&Item { + kind: ItemKind::Fn(..), + owner_id, + span, + .. + }) + | Node::TraitItem(&TraitItem { + kind: TraitItemKind::Fn(..), + owner_id, + span, + .. + }) + | Node::ImplItem(&ImplItem { + kind: ImplItemKind::Fn(..), + owner_id, + span, + .. + }) if span.ctxt() == ctxt => Some(ExprUseCtxt { + node: ExprUseNode::Return(owner_id), + adjustments, + is_ty_unified, + moved_before_use, + }), + + Node::ExprField(field) if field.span.ctxt() == ctxt => Some(ExprUseCtxt { + node: ExprUseNode::Field(field), + adjustments, + is_ty_unified, + moved_before_use, + }), + + Node::Expr(parent) if parent.span.ctxt() == ctxt => match parent.kind { + ExprKind::Ret(_) => Some(ExprUseCtxt { + node: ExprUseNode::Return(OwnerId { + def_id: cx.tcx.hir().body_owner_def_id(cx.enclosing_body.unwrap()), + }), + adjustments, + is_ty_unified, + moved_before_use, + }), + ExprKind::Closure(closure) => Some(ExprUseCtxt { + node: ExprUseNode::Return(OwnerId { def_id: closure.def_id }), + adjustments, + is_ty_unified, + moved_before_use, + }), + ExprKind::Call(func, args) => Some(ExprUseCtxt { + node: match args.iter().position(|arg| arg.hir_id == child_id) { + Some(i) => ExprUseNode::FnArg(func, i), + None => ExprUseNode::Callee, + }, + adjustments, + is_ty_unified, + moved_before_use, + }), + ExprKind::MethodCall(name, _, args, _) => Some(ExprUseCtxt { + node: ExprUseNode::MethodArg( + parent.hir_id, + name.args, + args.iter().position(|arg| arg.hir_id == child_id).map_or(0, |i| i + 1), + ), + adjustments, + is_ty_unified, + moved_before_use, + }), + ExprKind::Field(child, name) if child.hir_id == e.hir_id => Some(ExprUseCtxt { + node: ExprUseNode::FieldAccess(name), + adjustments, + is_ty_unified, + moved_before_use, + }), + ExprKind::If(e, _, _) | ExprKind::Match(e, _, _) if e.hir_id != child_id => { + is_ty_unified = true; + moved_before_use = true; + None + }, + ExprKind::Block(_, Some(_)) | ExprKind::Break(..) => { + is_ty_unified = true; + moved_before_use = true; + None + }, + ExprKind::Block(..) => { + moved_before_use = true; + None + }, + _ => None, + }, + _ => None, + } + }) +} + /// Tokenizes the input while keeping the text associated with each token. pub fn tokenize_with_text(s: &str) -> impl Iterator<Item = (TokenKind, &str)> { let mut pos = 0; |