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fix: manual_unwrap_or_default suggests error when expression is a None variant #12688

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fix: manual_unwrap_or_default suggests error when expression is a None variant #12688

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c9f0374
fix: manual_unwrap_or_default
t-webber Apr 17, 2024
7316845
update tests
t-webber Apr 18, 2024
d7572b8
add: tests configuration in separate file
t-webber Jun 17, 2024
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38 changes: 37 additions & 1 deletion clippy_lints/src/manual_unwrap_or_default.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ use rustc_errors::Applicability;
use rustc_hir::def::Res;
use rustc_hir::{Arm, Expr, ExprKind, HirId, LangItem, MatchSource, Pat, PatKind, QPath};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::ty::GenericArgKind;
use rustc_middle::ty::{self, GenericArgKind};
use rustc_session::declare_lint_pass;
use rustc_span::sym;

Expand Down Expand Up @@ -148,6 +148,42 @@ fn handle<'tcx>(cx: &LateContext<'tcx>, if_let_or_match: IfLetOrMatch<'tcx>, exp
&& is_default_equivalent(cx, body_none)
&& let Some(receiver) = Sugg::hir_opt(cx, condition).map(Sugg::maybe_par)
{
// We check if the expression is not a None variant
if let Some(none_def_id) = cx.tcx.lang_items().option_none_variant() {
if let ExprKind::Path(QPath::Resolved(_, path)) = &condition.kind {
if let Some(def_id) = path.res.opt_def_id() {
if cx.tcx.parent(def_id) == none_def_id {
Comment on lines +152 to +155
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This is equivalent to path_res(cx, condition).opt_def_id().is_some_and(|id| Some(cx.tcx.parent(id)) == cx.tcx.lang_items().option_none_variant())

return span_lint_and_sugg(
cx,
MANUAL_UNWRAP_OR_DEFAULT,
expr.span,
format!("{expr_name} can be simplified with `.unwrap_or_default()`"),
"replace it with",
format!("{receiver}::</* Type */>.unwrap_or_default()"),
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You can print any Ty which will print the type's full name. The following should work:

if let ty::Adt(_, args) = cx.typeck_results().expr_ty(expr).kind()
  && let Some(arg) = args.first()
  && let Some(arg_ty) = arg.as_type()
{
  format!("{receiver}::<{}>.unwrap_or_default()", arg_ty)
}

Applicability::HasPlaceholders,
);
}
}
}
}

// We check if the expression is not a method or function with a unspecified return type
if let ExprKind::MethodCall(_, expr, _, _) = &condition.kind {
if let ty::Adt(_, substs) = cx.typeck_results().expr_ty(expr).kind() {
if let Some(ok_type) = substs.first() {
return span_lint_and_sugg(
cx,
MANUAL_UNWRAP_OR_DEFAULT,
expr.span,
format!("{expr_name} can be simplified with `.unwrap_or_default()`"),
format!("explicit the type {ok_type} and replace your expression with"),
format!("{receiver}.unwrap_or_default()"),
Applicability::Unspecified,
);
}
}
}
Comment on lines +170 to +185
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What are you trying to catch with this? This looks like it will just catch any scrutinee that happens to be a method call.

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I catch all methods and functions that return a generic type that can't be inferred from it's arguments (e.g. "1".parse()) ?

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We have clippy_utils::ty::expr_type_is_certain for that.


// Machine applicable only if there are no comments present
let applicability = if span_contains_comment(cx.sess().source_map(), expr.span) {
Applicability::MaybeIncorrect
Expand Down
74 changes: 0 additions & 74 deletions tests/ui/manual_unwrap_or_default.fixed
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This file was deleted.

16 changes: 16 additions & 0 deletions tests/ui/manual_unwrap_or_default.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -96,3 +96,19 @@ fn issue_12569() {
0
};
}

//@no-rustfix
fn issue_12670() {
// no auto: type not found
#[allow(clippy::match_result_ok)]
let _ = if let Some(x) = "1".parse().ok() {
x
} else {
i32::default()
};
let _ = if let Some(x) = None { x } else { i32::default() };
// auto fix with unwrap_or_default
let a: Option<i32> = None;
let _ = if let Some(x) = a { x } else { i32::default() };
let _ = if let Some(x) = Some(99) { x } else { i32::default() };
}
26 changes: 25 additions & 1 deletion tests/ui/manual_unwrap_or_default.stderr
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Expand Up @@ -62,5 +62,29 @@ LL | | _ => 0,
LL | | },
| |_________^ help: replace it with: `(*b).unwrap_or_default()`

error: aborting due to 6 previous errors
error: if let can be simplified with `.unwrap_or_default()`
--> tests/ui/manual_unwrap_or_default.rs:104:30
|
LL | let _ = if let Some(x) = "1".parse().ok() {
| ^^^^^^^^^^^ help: explicit the type i32 and replace your expression with: `"1".parse().ok().unwrap_or_default()`

error: if let can be simplified with `.unwrap_or_default()`
--> tests/ui/manual_unwrap_or_default.rs:109:13
|
LL | let _ = if let Some(x) = None { x } else { i32::default() };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `None::</* Type */>.unwrap_or_default()`

error: if let can be simplified with `.unwrap_or_default()`
--> tests/ui/manual_unwrap_or_default.rs:112:13
|
LL | let _ = if let Some(x) = a { x } else { i32::default() };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `a.unwrap_or_default()`

error: if let can be simplified with `.unwrap_or_default()`
--> tests/ui/manual_unwrap_or_default.rs:113:13
|
LL | let _ = if let Some(x) = Some(99) { x } else { i32::default() };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `Some(99).unwrap_or_default()`

error: aborting due to 10 previous errors