-// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
use crate::utils::{get_parent_expr, span_lint, span_note_and_lint};
use if_chain::if_chain;
use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
use rustc::hir::*;
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use rustc::ty;
-use rustc::{declare_tool_lint, lint_array};
-use syntax::ast;
+use rustc::{declare_lint_pass, declare_tool_lint};
-/// **What it does:** Checks for a read and a write to the same variable where
-/// whether the read occurs before or after the write depends on the evaluation
-/// order of sub-expressions.
-///
-/// **Why is this bad?** It is often confusing to read. In addition, the
-/// sub-expression evaluation order for Rust is not well documented.
-///
-/// **Known problems:** Code which intentionally depends on the evaluation
-/// order, or which is correct for any evaluation order.
-///
-/// **Example:**
-/// ```rust
-/// let mut x = 0;
-/// let a = {
-/// x = 1;
-/// 1
-/// } + x;
-/// // Unclear whether a is 1 or 2.
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for a read and a write to the same variable where
+ /// whether the read occurs before or after the write depends on the evaluation
+ /// order of sub-expressions.
+ ///
+ /// **Why is this bad?** It is often confusing to read. In addition, the
+ /// sub-expression evaluation order for Rust is not well documented.
+ ///
+ /// **Known problems:** Code which intentionally depends on the evaluation
+ /// order, or which is correct for any evaluation order.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// let mut x = 0;
+ /// let a = {
+ /// x = 1;
+ /// 1
+ /// } + x;
+ /// // Unclear whether a is 1 or 2.
+ /// ```
pub EVAL_ORDER_DEPENDENCE,
complexity,
"whether a variable read occurs before a write depends on sub-expression evaluation order"
}
-/// **What it does:** Checks for diverging calls that are not match arms or
-/// statements.
-///
-/// **Why is this bad?** It is often confusing to read. In addition, the
-/// sub-expression evaluation order for Rust is not well documented.
-///
-/// **Known problems:** Someone might want to use `some_bool || panic!()` as a
-/// shorthand.
-///
-/// **Example:**
-/// ```rust
-/// let a = b() || panic!() || c();
-/// // `c()` is dead, `panic!()` is only called if `b()` returns `false`
-/// let x = (a, b, c, panic!());
-/// // can simply be replaced by `panic!()`
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for diverging calls that are not match arms or
+ /// statements.
+ ///
+ /// **Why is this bad?** It is often confusing to read. In addition, the
+ /// sub-expression evaluation order for Rust is not well documented.
+ ///
+ /// **Known problems:** Someone might want to use `some_bool || panic!()` as a
+ /// shorthand.
+ ///
+ /// **Example:**
+ /// ```rust,no_run
+ /// # fn b() -> bool { true }
+ /// # fn c() -> bool { true }
+ /// let a = b() || panic!() || c();
+ /// // `c()` is dead, `panic!()` is only called if `b()` returns `false`
+ /// let x = (a, b, c, panic!());
+ /// // can simply be replaced by `panic!()`
+ /// ```
pub DIVERGING_SUB_EXPRESSION,
complexity,
"whether an expression contains a diverging sub expression"
}
-#[derive(Copy, Clone)]
-pub struct EvalOrderDependence;
-
-impl LintPass for EvalOrderDependence {
- fn get_lints(&self) -> LintArray {
- lint_array!(EVAL_ORDER_DEPENDENCE, DIVERGING_SUB_EXPRESSION)
- }
-}
+declare_lint_pass!(EvalOrderDependence => [EVAL_ORDER_DEPENDENCE, DIVERGING_SUB_EXPRESSION]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for EvalOrderDependence {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if let ExprKind::Path(ref qpath) = lhs.node {
if let QPath::Resolved(_, ref path) = *qpath {
if path.segments.len() == 1 {
- if let def::Def::Local(var) = cx.tables.qpath_def(qpath, lhs.hir_id) {
+ if let def::Res::Local(var) = cx.tables.qpath_res(qpath, lhs.hir_id) {
let mut visitor = ReadVisitor {
cx,
var,
}
fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, stmt: &'tcx Stmt) {
match stmt.node {
- StmtKind::Expr(ref e, _) | StmtKind::Semi(ref e, _) => DivergenceVisitor { cx }.maybe_walk_expr(e),
- StmtKind::Decl(ref d, _) => {
- if let DeclKind::Local(ref local) = d.node {
- if let Local { init: Some(ref e), .. } = **local {
- DivergenceVisitor { cx }.visit_expr(e);
- }
+ StmtKind::Local(ref local) => {
+ if let Local { init: Some(ref e), .. } = **local {
+ DivergenceVisitor { cx }.visit_expr(e);
}
},
+ StmtKind::Expr(ref e) | StmtKind::Semi(ref e) => DivergenceVisitor { cx }.maybe_walk_expr(e),
+ StmtKind::Item(..) => {},
}
}
}
-struct DivergenceVisitor<'a, 'tcx: 'a> {
+struct DivergenceVisitor<'a, 'tcx> {
cx: &'a LateContext<'a, 'tcx>,
}
/// When such a read is found, the lint is triggered.
fn check_for_unsequenced_reads(vis: &mut ReadVisitor<'_, '_>) {
let map = &vis.cx.tcx.hir();
- let mut cur_id = vis.write_expr.id;
+ let mut cur_id = vis.write_expr.hir_id;
loop {
let parent_id = map.get_parent_node(cur_id);
if parent_id == cur_id {
}
fn check_expr<'a, 'tcx>(vis: &mut ReadVisitor<'a, 'tcx>, expr: &'tcx Expr) -> StopEarly {
- if expr.id == vis.last_expr.id {
+ if expr.hir_id == vis.last_expr.hir_id {
return StopEarly::KeepGoing;
}
fn check_stmt<'a, 'tcx>(vis: &mut ReadVisitor<'a, 'tcx>, stmt: &'tcx Stmt) -> StopEarly {
match stmt.node {
- StmtKind::Expr(ref expr, _) | StmtKind::Semi(ref expr, _) => check_expr(vis, expr),
- StmtKind::Decl(ref decl, _) => {
- // If the declaration is of a local variable, check its initializer
- // expression if it has one. Otherwise, keep going.
- let local = match decl.node {
- DeclKind::Local(ref local) => Some(local),
- _ => None,
- };
- local
- .and_then(|local| local.init.as_ref())
- .map_or(StopEarly::KeepGoing, |expr| check_expr(vis, expr))
- },
+ StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => check_expr(vis, expr),
+ // If the declaration is of a local variable, check its initializer
+ // expression if it has one. Otherwise, keep going.
+ StmtKind::Local(ref local) => local
+ .init
+ .as_ref()
+ .map_or(StopEarly::KeepGoing, |expr| check_expr(vis, expr)),
+ _ => StopEarly::KeepGoing,
}
}
/// A visitor that looks for reads from a variable.
-struct ReadVisitor<'a, 'tcx: 'a> {
+struct ReadVisitor<'a, 'tcx> {
cx: &'a LateContext<'a, 'tcx>,
- /// The id of the variable we're looking for.
- var: ast::NodeId,
+ /// The ID of the variable we're looking for.
+ var: HirId,
/// The expressions where the write to the variable occurred (for reporting
/// in the lint).
write_expr: &'tcx Expr,
impl<'a, 'tcx> Visitor<'tcx> for ReadVisitor<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx Expr) {
- if expr.id == self.last_expr.id {
+ if expr.hir_id == self.last_expr.hir_id {
return;
}
if_chain! {
if let QPath::Resolved(None, ref path) = *qpath;
if path.segments.len() == 1;
- if let def::Def::Local(local_id) = self.cx.tables.qpath_def(qpath, expr.hir_id);
+ if let def::Res::Local(local_id) = self.cx.tables.qpath_res(qpath, expr.hir_id);
if local_id == self.var;
// Check that this is a read, not a write.
if !is_in_assignment_position(self.cx, expr);
}
}
-/// Returns true if `expr` is the LHS of an assignment, like `expr = ...`.
+/// Returns `true` if `expr` is the LHS of an assignment, like `expr = ...`.
fn is_in_assignment_position(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
if let Some(parent) = get_parent_expr(cx, expr) {
if let ExprKind::Assign(ref lhs, _) = parent.node {
- return lhs.id == expr.id;
+ return lhs.hir_id == expr.hir_id;
}
}
false