mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-23 13:13:34 +00:00
Move unnecessary_filter_map to a submodule
This commit is contained in:
Michael Wright
parent
db5c63b77a
commit
efdc739dfc
2 changed files with 148 additions and 140 deletions
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@ -1,6 +1,5 @@
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use crate::rustc::hir;
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use crate::rustc::hir::def::Def;
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use crate::rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
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use crate::rustc::lint::{in_external_macro, LateContext, LateLintPass, Lint, LintArray, LintContext, LintPass};
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use crate::rustc::ty::{self, Ty};
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use crate::rustc::{declare_tool_lint, lint_array};
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@ -9,7 +8,6 @@ use crate::syntax::ast;
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use crate::syntax::source_map::{BytePos, Span};
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use crate::utils::paths;
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use crate::utils::sugg;
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use crate::utils::usage::mutated_variables;
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use crate::utils::{
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get_arg_name, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of, is_self, is_self_ty,
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iter_input_pats, last_path_segment, match_def_path, match_path, match_qpath, match_trait_method, match_type,
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@ -22,6 +20,8 @@ use std::borrow::Cow;
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use std::fmt;
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use std::iter;
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mod unnecessary_filter_map;
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#[derive(Clone)]
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pub struct Pass;
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@ -1424,144 +1424,6 @@ fn lint_unnecessary_fold(cx: &LateContext<'_, '_>, expr: &hir::Expr, fold_args:
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};
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}
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mod unnecessary_filter_map {
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use super::*;
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pub(super) fn lint(cx: &LateContext<'_, '_>, expr: &hir::Expr, args: &[hir::Expr]) {
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if !match_trait_method(cx, expr, &paths::ITERATOR) {
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return;
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}
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if let hir::ExprKind::Closure(_, _, body_id, ..) = args[1].node {
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let body = cx.tcx.hir.body(body_id);
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let arg_id = body.arguments[0].pat.id;
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let mutates_arg = match mutated_variables(&body.value, cx) {
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Some(used_mutably) => used_mutably.contains(&arg_id),
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None => true,
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};
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let (mut found_mapping, mut found_filtering) = check_expression(&cx, arg_id, &body.value);
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let mut return_visitor = ReturnVisitor::new(&cx, arg_id);
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return_visitor.visit_expr(&body.value);
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found_mapping |= return_visitor.found_mapping;
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found_filtering |= return_visitor.found_filtering;
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if !found_filtering {
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span_lint(
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cx,
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UNNECESSARY_FILTER_MAP,
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expr.span,
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"this `.filter_map` can be written more simply using `.map`",
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);
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return;
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}
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if !found_mapping && !mutates_arg {
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span_lint(
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cx,
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UNNECESSARY_FILTER_MAP,
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expr.span,
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"this `.filter_map` can be written more simply using `.filter`",
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);
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return;
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}
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}
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}
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// returns (found_mapping, found_filtering)
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fn check_expression<'a, 'tcx: 'a>(cx: &'a LateContext<'a, 'tcx>, arg_id: ast::NodeId, expr: &'tcx hir::Expr) -> (bool, bool) {
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match &expr.node {
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hir::ExprKind::Call(ref func, ref args) => {
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if_chain! {
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if let hir::ExprKind::Path(ref path) = func.node;
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then {
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if match_qpath(path, &paths::OPTION_SOME) {
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if_chain! {
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if let hir::ExprKind::Path(path) = &args[0].node;
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if let Def::Local(ref local) = cx.tables.qpath_def(path, args[0].hir_id);
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then {
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if arg_id == *local {
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return (false, false)
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}
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}
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}
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return (true, false);
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} else {
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// We don't know. It might do anything.
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return (true, true);
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}
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}
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}
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(true, true)
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},
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hir::ExprKind::Block(ref block, _) => {
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if let Some(expr) = &block.expr {
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check_expression(cx, arg_id, &expr)
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} else {
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(false, false)
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}
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},
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// There must be an else_arm or there will be a type error
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hir::ExprKind::If(_, ref if_arm, Some(ref else_arm)) => {
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let if_check = check_expression(cx, arg_id, if_arm);
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let else_check = check_expression(cx, arg_id, else_arm);
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(if_check.0 | else_check.0, if_check.1 | else_check.1)
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},
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hir::ExprKind::Match(_, ref arms, _) => {
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let mut found_mapping = false;
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let mut found_filtering = false;
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for arm in arms {
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let (m, f) = check_expression(cx, arg_id, &arm.body);
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found_mapping |= m;
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found_filtering |= f;
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}
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(found_mapping, found_filtering)
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},
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hir::ExprKind::Path(path) if match_qpath(path, &paths::OPTION_NONE) => (false, true),
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_ => (true, true)
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}
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}
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struct ReturnVisitor<'a, 'tcx: 'a> {
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cx: &'a LateContext<'a, 'tcx>,
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arg_id: ast::NodeId,
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// Found a non-None return that isn't Some(input)
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found_mapping: bool,
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// Found a return that isn't Some
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found_filtering: bool,
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}
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impl<'a, 'tcx: 'a> ReturnVisitor<'a, 'tcx> {
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fn new(cx: &'a LateContext<'a, 'tcx>, arg_id: ast::NodeId) -> ReturnVisitor<'a, 'tcx> {
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ReturnVisitor {
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cx,
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arg_id,
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found_mapping: false,
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found_filtering: false,
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}
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}
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}
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impl<'a, 'tcx> Visitor<'tcx> for ReturnVisitor<'a, 'tcx> {
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fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
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if let hir::ExprKind::Ret(Some(expr)) = &expr.node {
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let (found_mapping, found_filtering) = check_expression(self.cx, self.arg_id, expr);
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self.found_mapping |= found_mapping;
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self.found_filtering |= found_filtering;
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} else {
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walk_expr(self, expr);
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}
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}
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fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
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NestedVisitorMap::None
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}
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}
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}
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fn lint_iter_nth(cx: &LateContext<'_, '_>, expr: &hir::Expr, iter_args: &[hir::Expr], is_mut: bool) {
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let mut_str = if is_mut { "_mut" } else { "" };
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let caller_type = if derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0])).is_some() {
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146
clippy_lints/src/methods/unnecessary_filter_map.rs
Normal file
146
clippy_lints/src/methods/unnecessary_filter_map.rs
Normal file
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@ -0,0 +1,146 @@
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use crate::rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
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use crate::rustc::lint::LateContext;
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use crate::rustc::hir;
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use crate::rustc::hir::def::Def;
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use crate::syntax::ast;
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use crate::utils::{match_qpath, match_trait_method, span_lint};
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use crate::utils::paths;
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use crate::utils::usage::mutated_variables;
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use if_chain::if_chain;
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use super::UNNECESSARY_FILTER_MAP;
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pub(super) fn lint(cx: &LateContext<'_, '_>, expr: &hir::Expr, args: &[hir::Expr]) {
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if !match_trait_method(cx, expr, &paths::ITERATOR) {
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return;
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}
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if let hir::ExprKind::Closure(_, _, body_id, ..) = args[1].node {
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let body = cx.tcx.hir.body(body_id);
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let arg_id = body.arguments[0].pat.id;
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let mutates_arg = match mutated_variables(&body.value, cx) {
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Some(used_mutably) => used_mutably.contains(&arg_id),
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None => true,
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};
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let (mut found_mapping, mut found_filtering) = check_expression(&cx, arg_id, &body.value);
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let mut return_visitor = ReturnVisitor::new(&cx, arg_id);
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return_visitor.visit_expr(&body.value);
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found_mapping |= return_visitor.found_mapping;
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found_filtering |= return_visitor.found_filtering;
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if !found_filtering {
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span_lint(
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cx,
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UNNECESSARY_FILTER_MAP,
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expr.span,
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"this `.filter_map` can be written more simply using `.map`",
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);
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return;
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}
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if !found_mapping && !mutates_arg {
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span_lint(
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cx,
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UNNECESSARY_FILTER_MAP,
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expr.span,
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"this `.filter_map` can be written more simply using `.filter`",
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);
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return;
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}
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}
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}
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// returns (found_mapping, found_filtering)
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fn check_expression<'a, 'tcx: 'a>(cx: &'a LateContext<'a, 'tcx>, arg_id: ast::NodeId, expr: &'tcx hir::Expr) -> (bool, bool) {
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match &expr.node {
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hir::ExprKind::Call(ref func, ref args) => {
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if_chain! {
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if let hir::ExprKind::Path(ref path) = func.node;
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then {
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if match_qpath(path, &paths::OPTION_SOME) {
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if_chain! {
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if let hir::ExprKind::Path(path) = &args[0].node;
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if let Def::Local(ref local) = cx.tables.qpath_def(path, args[0].hir_id);
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then {
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if arg_id == *local {
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return (false, false)
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}
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}
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}
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return (true, false);
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} else {
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// We don't know. It might do anything.
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return (true, true);
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}
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}
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}
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(true, true)
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},
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hir::ExprKind::Block(ref block, _) => {
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if let Some(expr) = &block.expr {
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check_expression(cx, arg_id, &expr)
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} else {
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(false, false)
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}
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},
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// There must be an else_arm or there will be a type error
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hir::ExprKind::If(_, ref if_arm, Some(ref else_arm)) => {
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let if_check = check_expression(cx, arg_id, if_arm);
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let else_check = check_expression(cx, arg_id, else_arm);
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(if_check.0 | else_check.0, if_check.1 | else_check.1)
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},
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hir::ExprKind::Match(_, ref arms, _) => {
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let mut found_mapping = false;
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let mut found_filtering = false;
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for arm in arms {
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let (m, f) = check_expression(cx, arg_id, &arm.body);
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found_mapping |= m;
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found_filtering |= f;
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}
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(found_mapping, found_filtering)
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},
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hir::ExprKind::Path(path) if match_qpath(path, &paths::OPTION_NONE) => (false, true),
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_ => (true, true)
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}
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}
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struct ReturnVisitor<'a, 'tcx: 'a> {
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cx: &'a LateContext<'a, 'tcx>,
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arg_id: ast::NodeId,
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// Found a non-None return that isn't Some(input)
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found_mapping: bool,
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// Found a return that isn't Some
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found_filtering: bool,
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}
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impl<'a, 'tcx: 'a> ReturnVisitor<'a, 'tcx> {
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fn new(cx: &'a LateContext<'a, 'tcx>, arg_id: ast::NodeId) -> ReturnVisitor<'a, 'tcx> {
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ReturnVisitor {
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cx,
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arg_id,
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found_mapping: false,
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found_filtering: false,
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}
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}
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}
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impl<'a, 'tcx> Visitor<'tcx> for ReturnVisitor<'a, 'tcx> {
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fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
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if let hir::ExprKind::Ret(Some(expr)) = &expr.node {
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let (found_mapping, found_filtering) = check_expression(self.cx, self.arg_id, expr);
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self.found_mapping |= found_mapping;
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self.found_filtering |= found_filtering;
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} else {
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walk_expr(self, expr);
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}
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}
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fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
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NestedVisitorMap::None
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}
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}
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