-// 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::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
-use crate::rustc::hir::*;
-use crate::syntax::ptr::P;
-use crate::syntax::ast::LitKind;
use crate::utils::{match_qpath, paths, snippet, span_lint_and_then};
-use crate::rustc_errors::Applicability;
+use rustc_errors::Applicability;
+use rustc_hir::*;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use syntax::ast::LitKind;
-/// **What it does:** Lint for redundant pattern matching over `Result` or
-/// `Option`
-///
-/// **Why is this bad?** It's more concise and clear to just use the proper
-/// utility function
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-///
-/// ```rust
-/// if let Ok(_) = Ok::<i32, i32>(42) {}
-/// if let Err(_) = Err::<i32, i32>(42) {}
-/// if let None = None::<()> {}
-/// if let Some(_) = Some(42) {}
-/// match Ok::<i32, i32>(42) {
-/// Ok(_) => true,
-/// Err(_) => false,
-/// };
-/// ```
-///
-/// The more idiomatic use would be:
-///
-/// ```rust
-/// if Ok::<i32, i32>(42).is_ok() {}
-/// if Err::<i32, i32>(42).is_err() {}
-/// if None::<()>.is_none() {}
-/// if Some(42).is_some() {}
-/// Ok::<i32, i32>(42).is_ok();
-/// ```
-///
declare_clippy_lint! {
+ /// **What it does:** Lint for redundant pattern matching over `Result` or
+ /// `Option`
+ ///
+ /// **Why is this bad?** It's more concise and clear to just use the proper
+ /// utility function
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ ///
+ /// ```rust
+ /// if let Ok(_) = Ok::<i32, i32>(42) {}
+ /// if let Err(_) = Err::<i32, i32>(42) {}
+ /// if let None = None::<()> {}
+ /// if let Some(_) = Some(42) {}
+ /// match Ok::<i32, i32>(42) {
+ /// Ok(_) => true,
+ /// Err(_) => false,
+ /// };
+ /// ```
+ ///
+ /// The more idiomatic use would be:
+ ///
+ /// ```rust
+ /// if Ok::<i32, i32>(42).is_ok() {}
+ /// if Err::<i32, i32>(42).is_err() {}
+ /// if None::<()>.is_none() {}
+ /// if Some(42).is_some() {}
+ /// Ok::<i32, i32>(42).is_ok();
+ /// ```
pub REDUNDANT_PATTERN_MATCHING,
style,
"use the proper utility function avoiding an `if let`"
}
-#[derive(Copy, Clone)]
-pub struct Pass;
-
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(REDUNDANT_PATTERN_MATCHING)
- }
-}
+declare_lint_pass!(RedundantPatternMatching => [REDUNDANT_PATTERN_MATCHING]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
- #[allow(clippy::similar_names)]
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
- if let ExprKind::Match(ref op, ref arms, ref match_source) = expr.node {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for RedundantPatternMatching {
+ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+ if let ExprKind::Match(op, arms, ref match_source) = &expr.kind {
match match_source {
MatchSource::Normal => find_sugg_for_match(cx, expr, op, arms),
- MatchSource::IfLetDesugar { .. } => find_sugg_for_if_let(cx, expr, op, arms),
+ MatchSource::IfLetDesugar { contains_else_clause } => {
+ find_sugg_for_if_let(cx, expr, op, arms, *contains_else_clause)
+ },
_ => return,
}
}
fn find_sugg_for_if_let<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
- expr: &'tcx Expr,
- op: &P<Expr>,
- arms: &HirVec<Arm>
+ expr: &'tcx Expr<'_>,
+ op: &Expr<'_>,
+ arms: &[Arm<'_>],
+ has_else: bool,
) {
- if arms[0].pats.len() == 1 {
- let good_method = match arms[0].pats[0].node {
- PatKind::TupleStruct(ref path, ref pats, _) if pats.len() == 1 => {
- if let PatKind::Wild = pats[0].node {
- if match_qpath(path, &paths::RESULT_OK) {
- "is_ok()"
- } else if match_qpath(path, &paths::RESULT_ERR) {
- "is_err()"
- } else if match_qpath(path, &paths::OPTION_SOME) {
- "is_some()"
- } else {
- return;
- }
+ let good_method = match arms[0].pat.kind {
+ PatKind::TupleStruct(ref path, ref patterns, _) if patterns.len() == 1 => {
+ if let PatKind::Wild = patterns[0].kind {
+ if match_qpath(path, &paths::RESULT_OK) {
+ "is_ok()"
+ } else if match_qpath(path, &paths::RESULT_ERR) {
+ "is_err()"
+ } else if match_qpath(path, &paths::OPTION_SOME) {
+ "is_some()"
} else {
return;
}
- },
+ } else {
+ return;
+ }
+ },
- PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => "is_none()",
+ PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => "is_none()",
- _ => return,
- };
+ _ => return,
+ };
- span_lint_and_then(
- cx,
- REDUNDANT_PATTERN_MATCHING,
- arms[0].pats[0].span,
- &format!("redundant pattern matching, consider using `{}`", good_method),
- |db| {
- let span = expr.span.to(op.span);
- db.span_suggestion_with_applicability(
- span,
- "try this",
- format!("if {}.{}", snippet(cx, op.span, "_"), good_method),
- Applicability::MachineApplicable, // snippet
- );
- },
- );
- } else {
- return;
- }
+ let maybe_semi = if has_else { "" } else { ";" };
+
+ span_lint_and_then(
+ cx,
+ REDUNDANT_PATTERN_MATCHING,
+ arms[0].pat.span,
+ &format!("redundant pattern matching, consider using `{}`", good_method),
+ |db| {
+ let span = expr.span.to(op.span);
+ db.span_suggestion(
+ span,
+ "try this",
+ format!("{}.{}{}", snippet(cx, op.span, "_"), good_method, maybe_semi),
+ Applicability::MaybeIncorrect, // snippet
+ );
+ },
+ );
}
-fn find_sugg_for_match<'a, 'tcx>(
- cx: &LateContext<'a, 'tcx>,
- expr: &'tcx Expr,
- op: &P<Expr>,
- arms: &HirVec<Arm>
-) {
+fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>, op: &Expr<'_>, arms: &[Arm<'_>]) {
if arms.len() == 2 {
- let node_pair = (&arms[0].pats[0].node, &arms[1].pats[0].node);
+ let node_pair = (&arms[0].pat.kind, &arms[1].pat.kind);
let found_good_method = match node_pair {
(
- PatKind::TupleStruct(ref path_left, ref pats_left, _),
- PatKind::TupleStruct(ref path_right, ref pats_right, _)
- ) if pats_left.len() == 1 && pats_right.len() == 1 => {
- if let (PatKind::Wild, PatKind::Wild) = (&pats_left[0].node, &pats_right[0].node) {
+ PatKind::TupleStruct(ref path_left, ref patterns_left, _),
+ PatKind::TupleStruct(ref path_right, ref patterns_right, _),
+ ) if patterns_left.len() == 1 && patterns_right.len() == 1 => {
+ if let (PatKind::Wild, PatKind::Wild) = (&patterns_left[0].kind, &patterns_right[0].kind) {
find_good_method_for_match(
arms,
path_left,
&paths::RESULT_OK,
&paths::RESULT_ERR,
"is_ok()",
- "is_err()"
+ "is_err()",
)
} else {
None
}
},
- (
- PatKind::TupleStruct(ref path_left, ref pats, _),
- PatKind::Path(ref path_right)
- ) | (
- PatKind::Path(ref path_left),
- PatKind::TupleStruct(ref path_right, ref pats, _)
- ) if pats.len() == 1 => {
- if let PatKind::Wild = pats[0].node {
+ (PatKind::TupleStruct(ref path_left, ref patterns, _), PatKind::Path(ref path_right))
+ | (PatKind::Path(ref path_left), PatKind::TupleStruct(ref path_right, ref patterns, _))
+ if patterns.len() == 1 =>
+ {
+ if let PatKind::Wild = patterns[0].kind {
find_good_method_for_match(
arms,
path_left,
&paths::OPTION_SOME,
&paths::OPTION_NONE,
"is_some()",
- "is_none()"
+ "is_none()",
)
} else {
None
&format!("redundant pattern matching, consider using `{}`", good_method),
|db| {
let span = expr.span.to(op.span);
- db.span_suggestion_with_applicability(
+ db.span_suggestion(
span,
"try this",
format!("{}.{}", snippet(cx, op.span, "_"), good_method),
- Applicability::MachineApplicable, // snippet
+ Applicability::MaybeIncorrect, // snippet
);
},
);
}
- } else {
- return;
}
}
fn find_good_method_for_match<'a>(
- arms: &HirVec<Arm>,
- path_left: &QPath,
- path_right: &QPath,
+ arms: &[Arm<'_>],
+ path_left: &QPath<'_>,
+ path_right: &QPath<'_>,
expected_left: &[&str],
expected_right: &[&str],
should_be_left: &'a str,
- should_be_right: &'a str
+ should_be_right: &'a str,
) -> Option<&'a str> {
let body_node_pair = if match_qpath(path_left, expected_left) && match_qpath(path_right, expected_right) {
- (&(*arms[0].body).node, &(*arms[1].body).node)
+ (&(*arms[0].body).kind, &(*arms[1].body).kind)
} else if match_qpath(path_right, expected_left) && match_qpath(path_left, expected_right) {
- (&(*arms[1].body).node, &(*arms[0].body).node)
+ (&(*arms[1].body).kind, &(*arms[0].body).kind)
} else {
return None;
};
match body_node_pair {
- (ExprKind::Lit(ref lit_left), ExprKind::Lit(ref lit_right)) => {
- match (&lit_left.node, &lit_right.node) {
- (LitKind::Bool(true), LitKind::Bool(false)) => Some(should_be_left),
- (LitKind::Bool(false), LitKind::Bool(true)) => Some(should_be_right),
- _ => None,
- }
+ (ExprKind::Lit(ref lit_left), ExprKind::Lit(ref lit_right)) => match (&lit_left.node, &lit_right.node) {
+ (LitKind::Bool(true), LitKind::Bool(false)) => Some(should_be_left),
+ (LitKind::Bool(false), LitKind::Bool(true)) => Some(should_be_right),
+ _ => None,
},
_ => None,
}
projects / rust.git / blobdiff