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Include generic arguments when suggesting a closure η-reduction #14105

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merged 1 commit into from
Jan 30, 2025
+49 −28
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Include generic arguments when suggesting a closure η-reduction #14105

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13 changes: 9 additions & 4 deletions clippy_lints/src/eta_reduction.rs
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Original file line number Diff line number Diff line change
@@ -1,13 +1,13 @@
use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
use clippy_utils::higher::VecArgs;
use clippy_utils::source::snippet_opt;
use clippy_utils::source::{snippet_opt, snippet_with_applicability};
use clippy_utils::ty::get_type_diagnostic_name;
use clippy_utils::usage::{local_used_after_expr, local_used_in};
use clippy_utils::{
get_path_from_caller_to_method_type, is_adjusted, is_no_std_crate, path_to_local, path_to_local_id,
};
use rustc_errors::Applicability;
use rustc_hir::{BindingMode, Expr, ExprKind, FnRetTy, Param, PatKind, QPath, Safety, TyKind};
use rustc_hir::{BindingMode, Expr, ExprKind, FnRetTy, GenericArgs, Param, PatKind, QPath, Safety, TyKind};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty::{
Expand Down Expand Up @@ -239,6 +239,11 @@ fn check_closure<'tcx>(cx: &LateContext<'tcx>, outer_receiver: Option<&Expr<'tcx
&& !cx.tcx.has_attr(method_def_id, sym::track_caller)
&& check_sig(closure_sig, cx.tcx.fn_sig(method_def_id).skip_binder().skip_binder())
{
let mut app = Applicability::MachineApplicable;
let generic_args = match path.args.and_then(GenericArgs::span_ext) {
Some(span) => format!("::{}", snippet_with_applicability(cx, span, "<..>", &mut app)),
None => String::new(),
};
span_lint_and_then(
cx,
REDUNDANT_CLOSURE_FOR_METHOD_CALLS,
Expand All @@ -251,8 +256,8 @@ fn check_closure<'tcx>(cx: &LateContext<'tcx>, outer_receiver: Option<&Expr<'tcx
diag.span_suggestion(
expr.span,
"replace the closure with the method itself",
format!("{}::{}", type_name, path.ident.name),
Applicability::MachineApplicable,
format!("{}::{}{}", type_name, path.ident.name, generic_args),
app,
);
},
);
Expand Down
5 changes: 5 additions & 0 deletions tests/ui/eta.fixed
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Original file line number Diff line number Diff line change
Expand Up @@ -116,6 +116,11 @@ fn test_redundant_closures_containing_method_calls() {
t.iter().filter(|x| x.trait_foo_ref());
t.iter().map(|x| x.trait_foo_ref());
}

fn issue14096() {
let x = Some("42");
let _ = x.map(str::parse::<i16>);
}
}

struct Thunk<T>(Box<dyn FnMut() -> T>);
Expand Down
5 changes: 5 additions & 0 deletions tests/ui/eta.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -116,6 +116,11 @@ fn test_redundant_closures_containing_method_calls() {
t.iter().filter(|x| x.trait_foo_ref());
t.iter().map(|x| x.trait_foo_ref());
}

fn issue14096() {
let x = Some("42");
let _ = x.map(|x| x.parse::<i16>());
}
}

struct Thunk<T>(Box<dyn FnMut() -> T>);
Expand Down
54 changes: 30 additions & 24 deletions tests/ui/eta.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -71,142 +71,148 @@ LL | let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(|c| c.to_as
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `char::to_ascii_uppercase`

error: redundant closure
--> tests/ui/eta.rs:169:22
--> tests/ui/eta.rs:122:23
|
LL | let _ = x.map(|x| x.parse::<i16>());
| ^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `str::parse::<i16>`

error: redundant closure
--> tests/ui/eta.rs:174:22
|
LL | requires_fn_once(|| x());
| ^^^^^^ help: replace the closure with the function itself: `x`

error: redundant closure
--> tests/ui/eta.rs:176:27
--> tests/ui/eta.rs:181:27
|
LL | let a = Some(1u8).map(|a| foo_ptr(a));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `foo_ptr`

error: redundant closure
--> tests/ui/eta.rs:181:27
--> tests/ui/eta.rs:186:27
|
LL | let a = Some(1u8).map(|a| closure(a));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `closure`

error: redundant closure
--> tests/ui/eta.rs:213:28
--> tests/ui/eta.rs:218:28
|
LL | x.into_iter().for_each(|x| add_to_res(x));
| ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut add_to_res`

error: redundant closure
--> tests/ui/eta.rs:214:28
--> tests/ui/eta.rs:219:28
|
LL | y.into_iter().for_each(|x| add_to_res(x));
| ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut add_to_res`

error: redundant closure
--> tests/ui/eta.rs:215:28
--> tests/ui/eta.rs:220:28
|
LL | z.into_iter().for_each(|x| add_to_res(x));
| ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `add_to_res`

error: redundant closure
--> tests/ui/eta.rs:222:21
--> tests/ui/eta.rs:227:21
|
LL | Some(1).map(|n| closure(n));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut closure`

error: redundant closure
--> tests/ui/eta.rs:226:21
--> tests/ui/eta.rs:231:21
|
LL | Some(1).map(|n| in_loop(n));
| ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `in_loop`

error: redundant closure
--> tests/ui/eta.rs:319:18
--> tests/ui/eta.rs:324:18
|
LL | takes_fn_mut(|| f());
| ^^^^^^ help: replace the closure with the function itself: `&mut f`

error: redundant closure
--> tests/ui/eta.rs:322:19
--> tests/ui/eta.rs:327:19
|
LL | takes_fn_once(|| f());
| ^^^^^^ help: replace the closure with the function itself: `&mut f`

error: redundant closure
--> tests/ui/eta.rs:326:26
--> tests/ui/eta.rs:331:26
|
LL | move || takes_fn_mut(|| f_used_once())
| ^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut f_used_once`

error: redundant closure
--> tests/ui/eta.rs:338:19
--> tests/ui/eta.rs:343:19
|
LL | array_opt.map(|a| a.as_slice());
| ^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<[u8; 3]>::as_slice`

error: redundant closure
--> tests/ui/eta.rs:341:19
--> tests/ui/eta.rs:346:19
|
LL | slice_opt.map(|s| s.len());
| ^^^^^^^^^^^ help: replace the closure with the method itself: `<[u8]>::len`

error: redundant closure
--> tests/ui/eta.rs:344:17
--> tests/ui/eta.rs:349:17
|
LL | ptr_opt.map(|p| p.is_null());
| ^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<*const usize>::is_null`

error: redundant closure
--> tests/ui/eta.rs:348:17
--> tests/ui/eta.rs:353:17
|
LL | dyn_opt.map(|d| d.method_on_dyn());
| ^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<dyn TestTrait>::method_on_dyn`

error: redundant closure
--> tests/ui/eta.rs:408:19
--> tests/ui/eta.rs:413:19
|
LL | let _ = f(&0, |x, y| f2(x, y));
| ^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `f2`

error: redundant closure
--> tests/ui/eta.rs:436:22
--> tests/ui/eta.rs:441:22
|
LL | test.map(|t| t.method())
| ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `Test::method`

error: redundant closure
--> tests/ui/eta.rs:440:22
--> tests/ui/eta.rs:445:22
|
LL | test.map(|t| t.method())
| ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `super::Outer::method`

error: redundant closure
--> tests/ui/eta.rs:453:18
--> tests/ui/eta.rs:458:18
|
LL | test.map(|t| t.method())
| ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `test_mod::Test::method`

error: redundant closure
--> tests/ui/eta.rs:460:30
--> tests/ui/eta.rs:465:30
|
LL | test.map(|t| t.method())
| ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `crate::issue_10854::d::Test::method`

error: redundant closure
--> tests/ui/eta.rs:479:38
--> tests/ui/eta.rs:484:38
|
LL | let x = Box::new(|| None.map(|x| f(x)));
| ^^^^^^^^ help: replace the closure with the function itself: `&f`

error: redundant closure
--> tests/ui/eta.rs:483:38
--> tests/ui/eta.rs:488:38
|
LL | let x = Box::new(|| None.map(|x| f(x)));
| ^^^^^^^^ help: replace the closure with the function itself: `f`

error: redundant closure
--> tests/ui/eta.rs:500:35
--> tests/ui/eta.rs:505:35
|
LL | let _field = bind.or_else(|| get_default()).unwrap();
| ^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `get_default`

error: aborting due to 34 previous errors
error: aborting due to 35 previous errors