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;
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, MatchSource::IfLetDesugar { .. }) = expr.node {
- 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;
- }
- } else {
- return;
- }
- },
+ if let ExprKind::Match(ref op, ref arms, ref match_source) = expr.node {
+ match match_source {
+ MatchSource::Normal => find_sugg_for_match(cx, expr, op, arms),
+ MatchSource::IfLetDesugar { .. } => find_sugg_for_if_let(cx, expr, op, arms),
+ _ => return,
+ }
+ }
+ }
+}
- PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => "is_none()",
+fn find_sugg_for_if_let<'a, 'tcx>(
+ cx: &LateContext<'a, 'tcx>,
+ expr: &'tcx Expr,
+ op: &P<Expr>,
+ arms: &HirVec<Arm>
+) {
+ 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;
+ }
+ } else {
+ return;
+ }
+ },
- _ => return,
- };
+ PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => "is_none()",
- span_lint_and_then(
- cx,
- IF_LET_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
- );
- },
+ _ => return,
+ };
+
+ span_lint_and_then(
+ cx,
+ IF_LET_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;
+ }
+}
+
+fn find_sugg_for_match<'a, 'tcx>(
+ cx: &LateContext<'a, 'tcx>,
+ expr: &'tcx Expr,
+ op: &P<Expr>,
+ arms: &HirVec<Arm>
+) {
+ if arms.len() == 2 {
+ let node_pair = (&arms[0].pats[0].node, &arms[1].pats[0].node);
+
+ 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) {
+ find_good_method_for_match(
+ arms,
+ path_left,
+ path_right,
+ &paths::RESULT_OK,
+ &paths::RESULT_ERR,
+ "is_ok()",
+ "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 {
+ find_good_method_for_match(
+ arms,
+ path_left,
+ path_right,
+ &paths::OPTION_SOME,
+ &paths::OPTION_NONE,
+ "is_some()",
+ "is_none()"
+ )
+ } else {
+ None
+ }
+ },
+ _ => None,
+ };
+
+ if let Some(good_method) = found_good_method {
+ span_lint_and_then(
+ cx,
+ IF_LET_REDUNDANT_PATTERN_MATCHING,
+ expr.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!("{}.{}", snippet(cx, op.span, "_"), good_method),
+ Applicability::MachineApplicable, // snippet
+ );
+ },
+ );
}
+ } else {
+ return;
+ }
+}
+
+fn find_good_method_for_match<'a>(
+ arms: &HirVec<Arm>,
+ path_left: &QPath,
+ path_right: &QPath,
+ expected_left: &[&str],
+ expected_right: &[&str],
+ should_be_left: &'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)
+ } else if match_qpath(path_right, expected_left) && match_qpath(path_left, expected_right) {
+ (&(*arms[1].body).node, &(*arms[0].body).node)
+ } 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,
+ }
+ },
+ _ => None,
}
}
28 | | }
| |_____- help: try this: `if Some(42).is_some()`
-error: aborting due to 4 previous errors
+error: redundant pattern matching, consider using `is_ok()`
+ --> $DIR/if_let_redundant_pattern_matching.rs:46:5
+ |
+46 | / match Ok::<i32, i32>(42) {
+47 | | Ok(_) => true,
+48 | | Err(_) => false,
+49 | | };
+ | |_____^ help: try this: `Ok::<i32, i32>(42).is_ok()`
+
+error: redundant pattern matching, consider using `is_err()`
+ --> $DIR/if_let_redundant_pattern_matching.rs:51:5
+ |
+51 | / match Ok::<i32, i32>(42) {
+52 | | Ok(_) => false,
+53 | | Err(_) => true,
+54 | | };
+ | |_____^ help: try this: `Ok::<i32, i32>(42).is_err()`
+
+error: redundant pattern matching, consider using `is_err()`
+ --> $DIR/if_let_redundant_pattern_matching.rs:56:5
+ |
+56 | / match Err::<i32, i32>(42) {
+57 | | Ok(_) => false,
+58 | | Err(_) => true,
+59 | | };
+ | |_____^ help: try this: `Err::<i32, i32>(42).is_err()`
+
+error: redundant pattern matching, consider using `is_ok()`
+ --> $DIR/if_let_redundant_pattern_matching.rs:61:5
+ |
+61 | / match Err::<i32, i32>(42) {
+62 | | Ok(_) => true,
+63 | | Err(_) => false,
+64 | | };
+ | |_____^ help: try this: `Err::<i32, i32>(42).is_ok()`
+
+error: redundant pattern matching, consider using `is_some()`
+ --> $DIR/if_let_redundant_pattern_matching.rs:66:5
+ |
+66 | / match Some(42) {
+67 | | Some(_) => true,
+68 | | None => false,
+69 | | };
+ | |_____^ help: try this: `Some(42).is_some()`
+
+error: redundant pattern matching, consider using `is_none()`
+ --> $DIR/if_let_redundant_pattern_matching.rs:71:5
+ |
+71 | / match None::<()> {
+72 | | Some(_) => false,
+73 | | None => true,
+74 | | };
+ | |_____^ help: try this: `None::<()>.is_none()`
+
+error: aborting due to 10 previous errors