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make [manual_map] ignore types that contain dyn #12712

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make [manual_map] ignore types that contain dyn #12712

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78 changes: 74 additions & 4 deletions clippy_lints/src/matches/manual_utils.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,17 +3,19 @@ use crate::matches::MATCH_AS_REF;
use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
use clippy_utils::sugg::Sugg;
use clippy_utils::ty::{is_copy, is_type_diagnostic_item, peel_mid_ty_refs_is_mutable, type_is_unsafe_function};
use clippy_utils::visitors::for_each_expr;
use clippy_utils::{
can_move_expr_to_closure, is_else_clause, is_lint_allowed, is_res_lang_ctor, path_res, path_to_local_id,
peel_blocks, peel_hir_expr_refs, peel_hir_expr_while, CaptureKind,
can_move_expr_to_closure, is_else_clause, is_lint_allowed, is_res_lang_ctor, path_res, path_to_local,
path_to_local_id, peel_blocks, peel_hir_expr_refs, peel_hir_expr_while, CaptureKind,
};
use rustc_ast::util::parser::PREC_POSTFIX;
use rustc_errors::Applicability;
use rustc_hir::def::Res;
use rustc_hir::LangItem::{OptionNone, OptionSome};
use rustc_hir::{BindingMode, Expr, ExprKind, HirId, Mutability, Pat, PatKind, Path, QPath};
use rustc_hir::{BindingMode, Block, Expr, ExprKind, HirId, Mutability, Node, Pat, PatKind, Path, QPath};
use rustc_lint::LateContext;
use rustc_span::{sym, SyntaxContext};
use std::ops::ControlFlow;

#[expect(clippy::too_many_arguments)]
#[expect(clippy::too_many_lines)]
Expand Down Expand Up @@ -73,7 +75,7 @@ where
}

// `map` won't perform any adjustments.
if !cx.typeck_results().expr_adjustments(some_expr.expr).is_empty() {
if some_expr.expr_contains_ty_adjustments(cx) && expr_has_explicit_ty(cx, expr) {
return None;
}

Expand Down Expand Up @@ -238,6 +240,17 @@ impl<'tcx> SomeExpr<'tcx> {
let sugg = Sugg::hir_with_context(cx, self.expr, ctxt, "..", app);
if self.needs_negated { !sugg } else { sugg }
}

fn expr_contains_ty_adjustments(&self, cx: &LateContext<'tcx>) -> bool {
for_each_expr(self.expr, |ex| {
if cx.typeck_results().expr_adjustments(ex).is_empty() {
ControlFlow::Continue(())
} else {
ControlFlow::Break(true)
}
})
.unwrap_or_default()
}
}

// Try to parse into a recognized `Option` pattern.
Expand Down Expand Up @@ -274,3 +287,60 @@ pub(super) fn try_parse_pattern<'tcx>(
fn is_none_expr(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
is_res_lang_ctor(cx, path_res(cx, peel_blocks(expr)), OptionNone)
}

/// Return `true` if the type of `match` or `if-let` is labeled explicitly.
///
/// Such as the init binding of:
///
/// ```ignore
/// let x: &u8 = match Some(0) { .. };
/// // ^^^^^^^^^^^^^^^^^^^^
/// ```
///
/// Or the return of a function with return ty:
///
/// ```ignore
/// fn foo() -> u8 {
/// match Some(0) { .. }
/// // ^^^^^^^^^^^^^^^^^^^^
/// }
/// ```
fn expr_has_explicit_ty(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
fn check_inner_(cx: &LateContext<'_>, hir_id: HirId) -> bool {
match cx.tcx.parent_hir_node(hir_id) {
Node::LetStmt(let_stmt) => let_stmt.ty.is_some(),
Node::Expr(Expr {
kind: ExprKind::Assign(assignee, ..),
..
}) => {
if let Some(local_id) = path_to_local(assignee)
&& let Node::LetStmt(let_stmt) = cx.tcx.parent_hir_node(local_id)
{
let_stmt.ty.is_some()
} else {
false
}
},
// Assuming `true` because this branch should only be reached from
// tracing the parent of a `Node::Block` that has return value,
// meaning this is either `Fn` or `Const`, that always (?) has a labeled type.
Node::Item(_) | Node::TraitItem(_) | Node::ImplItem(_) |
// If this expr is being returned, then it's type must've been `labeled` on its owner function.
Node::Expr(Expr {
kind: ExprKind::Ret(_), ..
}) => true,
// The implicit return of a block, check if its a fn body or some init block.
Node::Block(Block {
expr: Some(_), hir_id, ..
}) => check_inner_(cx, cx.tcx.parent_hir_id(*hir_id)),
_ => false,
}
}

// Sanity check
assert!(
matches!(expr.kind, ExprKind::Match(..) | ExprKind::If(..)),
"must used on `match` or `if-let` expressions"
);
check_inner_(cx, expr.hir_id)
}
75 changes: 74 additions & 1 deletion tests/ui/manual_map_option_2.fixed
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Original file line number Diff line number Diff line change
Expand Up @@ -40,9 +40,14 @@ fn main() {
None => None,
};

// Lint. `s` is captured by reference, so no lifetime issues.
let s = Some(String::new());
// Lint. `s` is captured by reference, so no lifetime issues.
let _ = s.as_ref().map(|x| { if let Some(ref s) = s { (x.clone(), s) } else { panic!() } });
// Don't lint this, type of `s` is coercioned from `&String` to `&str`
let x: Option<(String, &str)> = match &s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
};

// Issue #7820
unsafe fn f(x: u32) -> u32 {
Expand All @@ -54,3 +59,71 @@ fn main() {
let _ = Some(0).map(|x| unsafe { f(x) });
let _ = Some(0).map(|x| unsafe { f(x) });
}

mod issue_12659 {
trait DummyTrait {}

fn foo<T: DummyTrait, F: Fn() -> Result<T, ()>>(f: F) {
// Don't lint
let _: Option<Result<Box<dyn DummyTrait>, ()>> = match Some(0) {
Some(_) => Some(match f() {
Ok(res) => Ok(Box::new(res)),
_ => Err(()),
}),
None => None,
};

let _: Option<Box<&[u8]>> = match Some(()) {
Some(_) => Some(Box::new(b"1234")),
None => None,
};

let x = String::new();
let _: Option<Box<&str>> = match Some(()) {
Some(_) => Some(Box::new(&x)),
None => None,
};

let _: Option<&str> = match Some(()) {
Some(_) => Some(&x),
None => None,
};

//~v ERROR: manual implementation of `Option::map`
let _ = Some(0).map(|_| match f() {
Ok(res) => Ok(Box::new(res)),
_ => Err(()),
});
}

fn with_fn_ret(s: &Option<String>) -> Option<(String, &str)> {
// Don't lint, `map` doesn't work as the return type is adjusted.
match s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
}
}

fn with_fn_ret_2(s: &Option<String>) -> Option<(String, &str)> {
if true {
// Don't lint, `map` doesn't work as the return type is adjusted.
return match s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
};
}
None
}

#[allow(clippy::needless_late_init)]
fn with_fn_ret_3<'a>(s: &'a Option<String>) -> Option<(String, &'a str)> {
let x: Option<(String, &'a str)>;
x = {
match s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
}
};
x
}
}
78 changes: 77 additions & 1 deletion tests/ui/manual_map_option_2.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -43,12 +43,17 @@ fn main() {
None => None,
};

// Lint. `s` is captured by reference, so no lifetime issues.
let s = Some(String::new());
// Lint. `s` is captured by reference, so no lifetime issues.
let _ = match &s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
};
// Don't lint this, type of `s` is coercioned from `&String` to `&str`
let x: Option<(String, &str)> = match &s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
};

// Issue #7820
unsafe fn f(x: u32) -> u32 {
Expand All @@ -69,3 +74,74 @@ fn main() {
None => None,
};
}

mod issue_12659 {
trait DummyTrait {}

fn foo<T: DummyTrait, F: Fn() -> Result<T, ()>>(f: F) {
// Don't lint
let _: Option<Result<Box<dyn DummyTrait>, ()>> = match Some(0) {
Some(_) => Some(match f() {
Ok(res) => Ok(Box::new(res)),
_ => Err(()),
}),
None => None,
};
Comment on lines +81 to +89
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The problem is that it doesn't catch the adjustment rather than the presence of a dyn, e.g. the same can occur with an unsized coercion

fn main() {
    let x: &[u8; 4] = b"1234";

    // ok
    let _: Option<Box<&[u8]>> = match Some(()) {
        Some(_) => Some(Box::new(x)),
        None => None,
    };

    // error[E0308]: mismatched types
    let _: Option<Box<&[u8]>> = Some(()).map(|_| Box::new(x));
}

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Oops, you're right, I'll see what I can do with it


let _: Option<Box<&[u8]>> = match Some(()) {
Some(_) => Some(Box::new(b"1234")),
None => None,
};

let x = String::new();
let _: Option<Box<&str>> = match Some(()) {
Some(_) => Some(Box::new(&x)),
None => None,
};

let _: Option<&str> = match Some(()) {
Some(_) => Some(&x),
None => None,
};

//~v ERROR: manual implementation of `Option::map`
let _ = match Some(0) {
Some(_) => Some(match f() {
Ok(res) => Ok(Box::new(res)),
_ => Err(()),
}),
None => None,
};
}

fn with_fn_ret(s: &Option<String>) -> Option<(String, &str)> {
// Don't lint, `map` doesn't work as the return type is adjusted.
match s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
}
}

fn with_fn_ret_2(s: &Option<String>) -> Option<(String, &str)> {
if true {
// Don't lint, `map` doesn't work as the return type is adjusted.
return match s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
};
}
None
}

#[allow(clippy::needless_late_init)]
fn with_fn_ret_3<'a>(s: &'a Option<String>) -> Option<(String, &'a str)> {
let x: Option<(String, &'a str)>;
x = {
match s {
Some(x) => Some({ if let Some(ref s) = s { (x.clone(), s) } else { panic!() } }),
None => None,
}
};
x
}
}
29 changes: 25 additions & 4 deletions tests/ui/manual_map_option_2.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ LL | | };
| |_____^ help: try: `s.as_ref().map(|x| { if let Some(ref s) = s { (x.clone(), s) } else { panic!() } })`

error: manual implementation of `Option::map`
--> tests/ui/manual_map_option_2.rs:58:17
--> tests/ui/manual_map_option_2.rs:63:17
|
LL | let _ = match Some(0) {
| _________________^
Expand All @@ -42,7 +42,7 @@ LL | | };
| |_________^ help: try: `Some(0).map(|x| f(x))`

error: manual implementation of `Option::map`
--> tests/ui/manual_map_option_2.rs:63:13
--> tests/ui/manual_map_option_2.rs:68:13
|
LL | let _ = match Some(0) {
| _____________^
Expand All @@ -52,7 +52,7 @@ LL | | };
| |_____^ help: try: `Some(0).map(|x| unsafe { f(x) })`

error: manual implementation of `Option::map`
--> tests/ui/manual_map_option_2.rs:67:13
--> tests/ui/manual_map_option_2.rs:72:13
|
LL | let _ = match Some(0) {
| _____________^
Expand All @@ -61,5 +61,26 @@ LL | | None => None,
LL | | };
| |_____^ help: try: `Some(0).map(|x| unsafe { f(x) })`

error: aborting due to 5 previous errors
error: manual implementation of `Option::map`
--> tests/ui/manual_map_option_2.rs:108:17
|
LL | let _ = match Some(0) {
| _________________^
LL | | Some(_) => Some(match f() {
LL | | Ok(res) => Ok(Box::new(res)),
LL | | _ => Err(()),
LL | | }),
LL | | None => None,
LL | | };
| |_________^
|
help: try
|
LL ~ let _ = Some(0).map(|_| match f() {
LL + Ok(res) => Ok(Box::new(res)),
LL + _ => Err(()),
LL ~ });
|

error: aborting due to 6 previous errors