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Moved to submodule, don't trigger if map_unwrap_or does

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Dániel Buga 2020-08-16 20:47:50 +02:00
parent 9c41822d34
commit d71b418ac5
2 changed files with 132 additions and 117 deletions
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136
clippy_lints/src/methods/mod.rs
View file

@ -3,6 +3,7 @@ mod inefficient_to_string;
mod manual_saturating_arithmetic;
mod option_map_unwrap_or;
mod unnecessary_filter_map;
mod unnecessary_lazy_eval;
use std::borrow::Cow;
use std::fmt;
@ -1436,17 +1437,18 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
["expect", ..] => lint_expect(cx, expr, arg_lists[0]),
["unwrap_or", "map"] => option_map_unwrap_or::lint(cx, expr, arg_lists[1], arg_lists[0], method_spans[1]),
["unwrap_or_else", "map"] => {
lint_lazy_eval(cx, expr, arg_lists[0], true, "unwrap_or");
lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]);
if !lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]) {
unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], true, "unwrap_or");
}
},
["map_or", ..] => lint_map_or_none(cx, expr, arg_lists[0]),
["and_then", ..] => {
lint_lazy_eval(cx, expr, arg_lists[0], false, "and");
unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], false, "and");
bind_instead_of_map::OptionAndThenSome::lint(cx, expr, arg_lists[0]);
bind_instead_of_map::ResultAndThenOk::lint(cx, expr, arg_lists[0]);
},
["or_else", ..] => {
lint_lazy_eval(cx, expr, arg_lists[0], false, "or");
unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], false, "or");
bind_instead_of_map::ResultOrElseErrInfo::lint(cx, expr, arg_lists[0]);
},
["next", "filter"] => lint_filter_next(cx, expr, arg_lists[1]),
@ -1490,9 +1492,9 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
["is_file", ..] => lint_filetype_is_file(cx, expr, arg_lists[0]),
["map", "as_ref"] => lint_option_as_ref_deref(cx, expr, arg_lists[1], arg_lists[0], false),
["map", "as_mut"] => lint_option_as_ref_deref(cx, expr, arg_lists[1], arg_lists[0], true),
["unwrap_or_else", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "unwrap_or"),
["get_or_insert_with", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "get_or_insert"),
["ok_or_else", ..] => lint_lazy_eval(cx, expr, arg_lists[0], true, "ok_or"),
["unwrap_or_else", ..] => unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], true, "unwrap_or"),
["get_or_insert_with", ..] => unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], true, "get_or_insert"),
["ok_or_else", ..] => unnecessary_lazy_eval::lint(cx, expr, arg_lists[0], true, "ok_or"),
_ => {},
}
@ -2708,119 +2710,13 @@ fn lint_map_flatten<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map
}
}
/// lint use of `<fn>_else(simple closure)` for `Option`s and `Result`s that can be
/// replaced with `<fn>(return value of simple closure)`
fn lint_lazy_eval<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
args: &'tcx [hir::Expr<'_>],
allow_variant_calls: bool,
simplify_using: &str,
) {
let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(option_type));
let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(result_type));
if !is_option && !is_result {
return;
}
// Return true if the expression is an accessor of any of the arguments
fn expr_uses_argument(expr: &hir::Expr<'_>, params: &[hir::Param<'_>]) -> bool {
params.iter().any(|arg| {
if_chain! {
if let hir::PatKind::Binding(_, _, ident, _) = arg.pat.kind;
if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind;
if let [p, ..] = path.segments;
then {
ident.name == p.ident.name
} else {
false
}
}
})
}
fn match_any_qpath(path: &hir::QPath<'_>, paths: &[&[&str]]) -> bool {
paths.iter().any(|candidate| match_qpath(path, candidate))
}
fn can_simplify(expr: &hir::Expr<'_>, params: &[hir::Param<'_>], variant_calls: bool) -> bool {
match expr.kind {
// Closures returning literals can be unconditionally simplified
hir::ExprKind::Lit(_) => true,
hir::ExprKind::Index(ref object, ref index) => {
// arguments are not being indexed into
if !expr_uses_argument(object, params) {
// arguments are not used as index
!expr_uses_argument(index, params)
} else {
false
}
},
// Reading fields can be simplified if the object is not an argument of the closure
hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params),
// Paths can be simplified if the root is not the argument, this also covers None
hir::ExprKind::Path(_) => !expr_uses_argument(expr, params),
// Calls to Some, Ok, Err can be considered literals if they don't derive an argument
hir::ExprKind::Call(ref func, ref args) => if_chain! {
if variant_calls; // Disable lint when rules conflict with bind_instead_of_map
if let hir::ExprKind::Path(ref path) = func.kind;
if match_any_qpath(path, &[&["Some"], &["Ok"], &["Err"]]);
then {
// Recursively check all arguments
args.iter().all(|arg| can_simplify(arg, params, variant_calls))
} else {
false
}
},
// For anything more complex than the above, a closure is probably the right solution,
// or the case is handled by an other lint
_ => false,
}
}
if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind {
let body = cx.tcx.hir().body(eid);
let ex = &body.value;
let params = &body.params;
if can_simplify(ex, params, allow_variant_calls) {
let msg = if is_option {
"unnecessary closure used to substitute value for `Option::None`"
} else {
"unnecessary closure used to substitute value for `Result::Err`"
};
span_lint_and_sugg(
cx,
UNNECESSARY_LAZY_EVALUATION,
expr.span,
msg,
&format!("Use `{}` instead", simplify_using),
format!(
"{0}.{1}({2})",
snippet(cx, args[0].span, ".."),
simplify_using,
snippet(cx, ex.span, ".."),
),
Applicability::MachineApplicable,
);
}
}
}
/// lint use of `map().unwrap_or_else()` for `Option`s and `Result`s
fn lint_map_unwrap_or_else<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
map_args: &'tcx [hir::Expr<'_>],
unwrap_args: &'tcx [hir::Expr<'_>],
) {
) -> bool {
// lint if the caller of `map()` is an `Option`
let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_args[0]), sym!(option_type));
let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_args[0]), sym!(result_type));
@ -2832,10 +2728,10 @@ fn lint_map_unwrap_or_else<'tcx>(
let unwrap_mutated_vars = mutated_variables(&unwrap_args[1], cx);
if let (Some(map_mutated_vars), Some(unwrap_mutated_vars)) = (map_mutated_vars, unwrap_mutated_vars) {
if map_mutated_vars.intersection(&unwrap_mutated_vars).next().is_some() {
return;
return false;
}
} else {
return;
return false;
}
// lint message
@ -2865,9 +2761,15 @@ fn lint_map_unwrap_or_else<'tcx>(
map_snippet, unwrap_snippet,
),
);
true
} else if same_span && multiline {
span_lint(cx, MAP_UNWRAP_OR, expr.span, msg);
};
true
} else {
false
}
} else {
false
}
}

113
clippy_lints/src/methods/unnecessary_lazy_eval.rs Normal file
View file

@ -0,0 +1,113 @@
use crate::utils::{match_qpath, span_lint_and_sugg, snippet, is_type_diagnostic_item};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::UNNECESSARY_LAZY_EVALUATION;
/// lint use of `<fn>_else(simple closure)` for `Option`s and `Result`s that can be
/// replaced with `<fn>(return value of simple closure)`
pub(super) fn lint<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
args: &'tcx [hir::Expr<'_>],
allow_variant_calls: bool,
simplify_using: &str,
) {
let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(option_type));
let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&args[0]), sym!(result_type));
if !is_option && !is_result {
return;
}
// Return true if the expression is an accessor of any of the arguments
fn expr_uses_argument(expr: &hir::Expr<'_>, params: &[hir::Param<'_>]) -> bool {
params.iter().any(|arg| {
if_chain! {
if let hir::PatKind::Binding(_, _, ident, _) = arg.pat.kind;
if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind;
if let [p, ..] = path.segments;
then {
ident.name == p.ident.name
} else {
false
}
}
})
}
fn match_any_qpath(path: &hir::QPath<'_>, paths: &[&[&str]]) -> bool {
paths.iter().any(|candidate| match_qpath(path, candidate))
}
fn can_simplify(expr: &hir::Expr<'_>, params: &[hir::Param<'_>], variant_calls: bool) -> bool {
match expr.kind {
// Closures returning literals can be unconditionally simplified
hir::ExprKind::Lit(_) => true,
hir::ExprKind::Index(ref object, ref index) => {
// arguments are not being indexed into
if !expr_uses_argument(object, params) {
// arguments are not used as index
!expr_uses_argument(index, params)
} else {
false
}
},
// Reading fields can be simplified if the object is not an argument of the closure
hir::ExprKind::Field(ref object, _) => !expr_uses_argument(object, params),
// Paths can be simplified if the root is not the argument, this also covers None
hir::ExprKind::Path(_) => !expr_uses_argument(expr, params),
// Calls to Some, Ok, Err can be considered literals if they don't derive an argument
hir::ExprKind::Call(ref func, ref args) => if_chain! {
if variant_calls; // Disable lint when rules conflict with bind_instead_of_map
if let hir::ExprKind::Path(ref path) = func.kind;
if match_any_qpath(path, &[&["Some"], &["Ok"], &["Err"]]);
then {
// Recursively check all arguments
args.iter().all(|arg| can_simplify(arg, params, variant_calls))
} else {
false
}
},
// For anything more complex than the above, a closure is probably the right solution,
// or the case is handled by an other lint
_ => false,
}
}
if let hir::ExprKind::Closure(_, _, eid, _, _) = args[1].kind {
let body = cx.tcx.hir().body(eid);
let ex = &body.value;
let params = &body.params;
if can_simplify(ex, params, allow_variant_calls) {
let msg = if is_option {
"unnecessary closure used to substitute value for `Option::None`"
} else {
"unnecessary closure used to substitute value for `Result::Err`"
};
span_lint_and_sugg(
cx,
UNNECESSARY_LAZY_EVALUATION,
expr.span,
msg,
&format!("Use `{}` instead", simplify_using),
format!(
"{0}.{1}({2})",
snippet(cx, args[0].span, ".."),
simplify_using,
snippet(cx, ex.span, ".."),
),
Applicability::MachineApplicable,
);
}
}
}