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get rid of unnecessary function pointer

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y21 2023-06-14 22:29:57 +02:00
parent c9daec2585
commit 69e892e3a1
1 changed files with 26 additions and 33 deletions
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59
clippy_lints/src/methods/unnecessary_fold.rs
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@ -12,14 +12,10 @@ use rustc_span::{source_map::Span, sym};
use super::UNNECESSARY_FOLD;
/// No turbofish needed in any case.
fn no_turbofish(_: &LateContext<'_>, _: &hir::Expr<'_>) -> bool {
false
}
/// Turbofish (`::<T>`) may be needed, but can be omitted if we are certain
/// that the type can be inferred from usage.
fn turbofish_if_not_inferred(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
/// Do we need to suggest turbofish when suggesting a replacement method?
/// Changing `fold` to `sum` needs it sometimes when the return type can't be
/// inferred. This checks for some common cases where it can be safely omitted
fn needs_turbofish(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
let parent = cx.tcx.hir().get_parent(expr.hir_id);
// some common cases where turbofish isn't needed:
@ -53,26 +49,7 @@ fn turbofish_if_not_inferred(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool
struct Replacement {
method_name: &'static str,
has_args: bool,
requires_turbofish: fn(&LateContext<'_>, &hir::Expr<'_>) -> bool,
}
impl Replacement {
/// `any(f)`, `all(f)`
pub fn non_generic(method_name: &'static str) -> Self {
Self {
method_name,
has_args: true,
requires_turbofish: no_turbofish,
}
}
/// `sum::<T>()`, `product::<T>()`
pub fn generic(method_name: &'static str) -> Self {
Self {
method_name,
has_args: false,
requires_turbofish: turbofish_if_not_inferred,
}
}
has_generic_return: bool,
}
pub(super) fn check(
@ -111,7 +88,7 @@ pub(super) fn check(
then {
let mut applicability = Applicability::MachineApplicable;
let turbofish = if (replacement.requires_turbofish)(cx, expr) {
let turbofish = if replacement.has_generic_return {
format!("::<{}>", cx.typeck_results().expr_ty_adjusted(right_expr).peel_refs())
} else {
String::new()
@ -159,7 +136,11 @@ pub(super) fn check(
acc,
fold_span,
hir::BinOpKind::Or,
Replacement::non_generic("any"),
Replacement {
has_args: true,
has_generic_return: false,
method_name: "any",
},
);
},
ast::LitKind::Bool(true) => {
@ -169,7 +150,11 @@ pub(super) fn check(
acc,
fold_span,
hir::BinOpKind::And,
Replacement::non_generic("all"),
Replacement {
has_args: true,
has_generic_return: false,
method_name: "all",
},
);
},
ast::LitKind::Int(0, _) => check_fold_with_op(
@ -178,7 +163,11 @@ pub(super) fn check(
acc,
fold_span,
hir::BinOpKind::Add,
Replacement::generic("sum"),
Replacement {
has_args: false,
has_generic_return: needs_turbofish(cx, expr),
method_name: "sum",
},
),
ast::LitKind::Int(1, _) => {
check_fold_with_op(
@ -187,7 +176,11 @@ pub(super) fn check(
acc,
fold_span,
hir::BinOpKind::Mul,
Replacement::generic("product"),
Replacement {
has_args: false,
has_generic_return: needs_turbofish(cx, expr),
method_name: "product",
},
);
},
_ => (),