Mirrors/rust-clippy
2
0
Fork 0
mirror of https://github.com/rust-lang/rust-clippy synced 2024-11-15 01:17:16 +00:00
Code Issues Projects Releases Packages Wiki Activity

Extract util functions from redundant_pattern_match

Browse source
This commit is contained in:
Jason Newcomb 2022-04-08 12:55:48 -04:00
parent 70f1d0d8fd
commit 58434ae385
2 changed files with 131 additions and 84 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

84
clippy_lints/src/matches/redundant_pattern_match.rs
View file

@ -3,16 +3,13 @@ use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::source::snippet;
use clippy_utils::sugg::Sugg;
use clippy_utils::ty::needs_ordered_drop;
use clippy_utils::{higher, match_def_path};
use clippy_utils::{is_lang_ctor, is_trait_method, paths};
use clippy_utils::visitors::any_temporaries_need_ordered_drop;
use clippy_utils::{higher, is_lang_ctor, is_trait_method, match_def_path, paths};
use if_chain::if_chain;
use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::LangItem::{OptionNone, PollPending};
use rustc_hir::{
intravisit::{walk_expr, Visitor},
Arm, Block, Expr, ExprKind, Node, Pat, PatKind, QPath, UnOp,
};
use rustc_hir::{Arm, Expr, ExprKind, Node, Pat, PatKind, QPath, UnOp};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, subst::GenericArgKind, DefIdTree, Ty};
use rustc_span::sym;
@ -47,79 +44,6 @@ fn try_get_generic_ty(ty: Ty<'_>, index: usize) -> Option<Ty<'_>> {
}
}
// Checks if there are any temporaries created in the given expression for which drop order
// matters.
fn temporaries_need_ordered_drop<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
struct V<'a, 'tcx> {
cx: &'a LateContext<'tcx>,
res: bool,
}
impl<'a, 'tcx> Visitor<'tcx> for V<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
match expr.kind {
// Taking the reference of a value leaves a temporary
// e.g. In `&String::new()` the string is a temporary value.
// Remaining fields are temporary values
// e.g. In `(String::new(), 0).1` the string is a temporary value.
ExprKind::AddrOf(_, _, expr) | ExprKind::Field(expr, _) => {
if !matches!(expr.kind, ExprKind::Path(_)) {
if needs_ordered_drop(self.cx, self.cx.typeck_results().expr_ty(expr)) {
self.res = true;
} else {
self.visit_expr(expr);
}
}
},
// the base type is always taken by reference.
// e.g. In `(vec![0])[0]` the vector is a temporary value.
ExprKind::Index(base, index) => {
if !matches!(base.kind, ExprKind::Path(_)) {
if needs_ordered_drop(self.cx, self.cx.typeck_results().expr_ty(base)) {
self.res = true;
} else {
self.visit_expr(base);
}
}
self.visit_expr(index);
},
// Method calls can take self by reference.
// e.g. In `String::new().len()` the string is a temporary value.
ExprKind::MethodCall(_, [self_arg, args @ ..], _) => {
if !matches!(self_arg.kind, ExprKind::Path(_)) {
let self_by_ref = self
.cx
.typeck_results()
.type_dependent_def_id(expr.hir_id)
.map_or(false, |id| self.cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref());
if self_by_ref && needs_ordered_drop(self.cx, self.cx.typeck_results().expr_ty(self_arg)) {
self.res = true;
} else {
self.visit_expr(self_arg);
}
}
args.iter().for_each(|arg| self.visit_expr(arg));
},
// Either explicitly drops values, or changes control flow.
ExprKind::DropTemps(_)
| ExprKind::Ret(_)
| ExprKind::Break(..)
| ExprKind::Yield(..)
| ExprKind::Block(Block { expr: None, .. }, _)
| ExprKind::Loop(..) => (),
// Only consider the final expression.
ExprKind::Block(Block { expr: Some(expr), .. }, _) => self.visit_expr(expr),
_ => walk_expr(self, expr),
}
}
}
let mut v = V { cx, res: false };
v.visit_expr(expr);
v.res
}
fn find_sugg_for_if_let<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
@ -191,7 +115,7 @@ fn find_sugg_for_if_let<'tcx>(
// scrutinee would be, so they have to be considered as well.
// e.g. in `if let Some(x) = foo.lock().unwrap().baz.as_ref() { .. }` the lock will be held
// for the duration if body.
let needs_drop = needs_ordered_drop(cx, check_ty) || temporaries_need_ordered_drop(cx, let_expr);
let needs_drop = needs_ordered_drop(cx, check_ty) || any_temporaries_need_ordered_drop(cx, let_expr);
// check that `while_let_on_iterator` lint does not trigger
if_chain! {

131
clippy_utils/src/visitors.rs
View file

@ -1,16 +1,18 @@
use crate::ty::needs_ordered_drop;
use crate::{get_enclosing_block, path_to_local_id};
use core::ops::ControlFlow;
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def::{CtorKind, DefKind, Res};
use rustc_hir::intravisit::{self, walk_block, walk_expr, Visitor};
use rustc_hir::{
Arm, Block, BlockCheckMode, Body, BodyId, Expr, ExprKind, HirId, ItemId, ItemKind, Stmt, UnOp, UnsafeSource,
Unsafety,
Arm, Block, BlockCheckMode, Body, BodyId, Expr, ExprKind, HirId, ItemId, ItemKind, Let, QPath, Stmt, UnOp,
UnsafeSource, Unsafety,
};
use rustc_lint::LateContext;
use rustc_middle::hir::map::Map;
use rustc_middle::hir::nested_filter;
use rustc_middle::ty;
use rustc_middle::ty::adjustment::Adjust;
use rustc_middle::ty::{self, Ty, TypeckResults};
/// Convenience method for creating a `Visitor` with just `visit_expr` overridden and nested
/// bodies (i.e. closures) are visited.
@ -494,3 +496,124 @@ pub fn for_each_local_use_after_expr<'tcx, B>(
ControlFlow::Continue(())
}
}
// Calls the given function for every unconsumed temporary created by the expression. Note the
// function is only guaranteed to be called for types which need to be dropped, but it may be called
// for other types.
pub fn for_each_unconsumed_temporary<'tcx, B>(
cx: &LateContext<'tcx>,
e: &'tcx Expr<'tcx>,
mut f: impl FnMut(Ty<'tcx>) -> ControlFlow<B>,
) -> ControlFlow<B> {
// Todo: Handle partially consumed values.
fn helper<'tcx, B>(
typeck: &'tcx TypeckResults<'tcx>,
consume: bool,
e: &'tcx Expr<'tcx>,
f: &mut impl FnMut(Ty<'tcx>) -> ControlFlow<B>,
) -> ControlFlow<B> {
if !consume
|| matches!(
typeck.expr_adjustments(e),
[adjust, ..] if matches!(adjust.kind, Adjust::Borrow(_) | Adjust::Deref(_))
)
{
match e.kind {
ExprKind::Path(QPath::Resolved(None, p))
if matches!(p.res, Res::Def(DefKind::Ctor(_, CtorKind::Const), _)) =>
{
f(typeck.expr_ty(e))?;
},
ExprKind::Path(_)
| ExprKind::Unary(UnOp::Deref, _)
| ExprKind::Index(..)
| ExprKind::Field(..)
| ExprKind::AddrOf(..) => (),
_ => f(typeck.expr_ty(e))?,
}
}
match e.kind {
ExprKind::AddrOf(_, _, e)
| ExprKind::Field(e, _)
| ExprKind::Unary(UnOp::Deref, e)
| ExprKind::Match(e, ..)
| ExprKind::Let(&Let { init: e, .. }) => {
helper(typeck, false, e, f)?;
},
ExprKind::Block(&Block { expr: Some(e), .. }, _)
| ExprKind::Box(e)
| ExprKind::Cast(e, _)
| ExprKind::Unary(_, e) => {
helper(typeck, true, e, f)?;
},
ExprKind::Call(callee, args) => {
helper(typeck, true, callee, f)?;
for arg in args {
helper(typeck, true, arg, f)?;
}
},
ExprKind::MethodCall(_, args, _) | ExprKind::Tup(args) | ExprKind::Array(args) => {
for arg in args {
helper(typeck, true, arg, f)?;
}
},
ExprKind::Index(borrowed, consumed)
| ExprKind::Assign(borrowed, consumed, _)
| ExprKind::AssignOp(_, borrowed, consumed) => {
helper(typeck, false, borrowed, f)?;
helper(typeck, true, consumed, f)?;
},
ExprKind::Binary(_, lhs, rhs) => {
helper(typeck, true, lhs, f)?;
helper(typeck, true, rhs, f)?;
},
ExprKind::Struct(_, fields, default) => {
for field in fields {
helper(typeck, true, field.expr, f)?;
}
if let Some(default) = default {
helper(typeck, false, default, f)?;
}
},
ExprKind::If(cond, then, else_expr) => {
helper(typeck, true, cond, f)?;
helper(typeck, true, then, f)?;
if let Some(else_expr) = else_expr {
helper(typeck, true, else_expr, f)?;
}
},
ExprKind::Type(e, _) => {
helper(typeck, consume, e, f)?;
},
// Either drops temporaries, jumps out of the current expression, or has no sub expression.
ExprKind::DropTemps(_)
| ExprKind::Ret(_)
| ExprKind::Break(..)
| ExprKind::Yield(..)
| ExprKind::Block(..)
| ExprKind::Loop(..)
| ExprKind::Repeat(..)
| ExprKind::Lit(_)
| ExprKind::ConstBlock(_)
| ExprKind::Closure { .. }
| ExprKind::Path(_)
| ExprKind::Continue(_)
| ExprKind::InlineAsm(_)
| ExprKind::Err => (),
}
ControlFlow::Continue(())
}
helper(cx.typeck_results(), true, e, &mut f)
}
pub fn any_temporaries_need_ordered_drop<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'tcx>) -> bool {
for_each_unconsumed_temporary(cx, e, |ty| {
if needs_ordered_drop(cx, ty) {
ControlFlow::Break(())
} else {
ControlFlow::Continue(())
}
})
.is_break()
}