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Fix if_then_some_else_none FP when require type coercion #15267

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Fix if_then_some_else_none FP when require type coercion #15267

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4 changes: 3 additions & 1 deletion clippy_lints/src/if_then_some_else_none.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,8 @@ use clippy_utils::msrvs::{self, Msrv};
use clippy_utils::source::snippet_with_context;
use clippy_utils::sugg::Sugg;
use clippy_utils::{
contains_return, higher, is_else_clause, is_in_const_context, is_res_lang_ctor, path_res, peel_blocks,
contains_return, expr_requires_coercion, higher, is_else_clause, is_in_const_context, is_res_lang_ctor, path_res,
peel_blocks,
};
use rustc_errors::Applicability;
use rustc_hir::LangItem::{OptionNone, OptionSome};
Expand Down Expand Up @@ -79,6 +80,7 @@ impl<'tcx> LateLintPass<'tcx> for IfThenSomeElseNone {
&& !expr.span.in_external_macro(cx.sess().source_map())
&& self.msrv.meets(cx, msrvs::BOOL_THEN)
&& !contains_return(then_block.stmts)
&& !expr_requires_coercion(cx, then_expr)
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In this case, what do you think about, instead of completely discarding the block if it requires type coercion, we check if we're in a trait item function (we cannot change the signatures of those functions) and if we're in just a normal function, we emit a non-MachineApplicable suggestion with a note about the user will have to modify the return type?

{
let method_name = if switch_to_eager_eval(cx, expr) && self.msrv.meets(cx, msrvs::BOOL_THEN_SOME) {
"then_some"
Expand Down
16 changes: 16 additions & 0 deletions tests/ui/if_then_some_else_none.fixed
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Original file line number Diff line number Diff line change
Expand Up @@ -122,3 +122,19 @@ const fn issue12103(x: u32) -> Option<u32> {
// Should not issue an error in `const` context
if x > 42 { Some(150) } else { None }
}

mod issue15257 {
#[derive(Default)]
pub struct Foo {}
pub trait Bar {}
impl Bar for Foo {}

#[allow(clippy::manual_is_multiple_of)]
fn maybe_get_bar(i: u32) -> Option<Box<dyn Bar>> {
if i % 2 == 0 {
Some(Box::new(Foo::default()))
} else {
None
}
}
}
16 changes: 16 additions & 0 deletions tests/ui/if_then_some_else_none.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -143,3 +143,19 @@ const fn issue12103(x: u32) -> Option<u32> {
// Should not issue an error in `const` context
if x > 42 { Some(150) } else { None }
}

mod issue15257 {
#[derive(Default)]
pub struct Foo {}
pub trait Bar {}
impl Bar for Foo {}

#[allow(clippy::manual_is_multiple_of)]
fn maybe_get_bar(i: u32) -> Option<Box<dyn Bar>> {
if i % 2 == 0 {
Some(Box::new(Foo::default()))
} else {
None
}
}
}
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