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Add support to returned refs from MethodCall
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@AlessioC31
AlessioC31 committed May 19, 2023
1 parent 4f6eafe commit be50a5f
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Showing 3 changed files with 83 additions and 46 deletions.
23 changes: 16 additions & 7 deletions clippy_lints/src/redundant_type_annotations.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -59,10 +59,8 @@ fn func_hir_id_to_func_ty<'tcx>(cx: &LateContext<'tcx>, hir_id: hir::hir_id::Hir
}

fn func_ty_to_return_type<'tcx>(cx: &LateContext<'tcx>, func_ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
if func_ty.is_fn()
&& let Some(return_type) = func_ty.fn_sig(cx.tcx).output().no_bound_vars()
{
Some(return_type)
if func_ty.is_fn() {
Some(func_ty.fn_sig(cx.tcx).output().skip_binder())
} else {
None
}
Expand Down Expand Up @@ -142,12 +140,23 @@ impl LateLintPass<'_> for RedundantTypeAnnotations {
}
},
hir::ExprKind::MethodCall(_, _, _, _) => {
if let hir::TyKind::Path(ty_path) = &ty.kind
&& let hir::QPath::Resolved(_, resolved_path_ty) = ty_path
let mut is_ref = false;
let mut ty_kind = &ty.kind;

// If the annotation is a ref we "peel" it
if let hir::TyKind::Ref(_, mut_ty) = &ty.kind {
is_ref = true;
ty_kind = &mut_ty.ty.kind;
}

if let hir::TyKind::Path(ty_path) = ty_kind
&& let hir::QPath::Resolved(_, resolved_path_ty) = ty_path
&& let Some(func_ty) = func_hir_id_to_func_ty(cx, init.hir_id)
&& let Some(return_type) = func_ty_to_return_type(cx, func_ty)
&& is_same_type(cx, resolved_path_ty.res, return_type)
&& is_same_type(cx, resolved_path_ty.res, match is_ref {
true => return_type.peel_refs(),
false => return_type,
})
{
span_lint(cx, REDUNDANT_TYPE_ANNOTATIONS, local.span, "redundant type annotation");
}
Expand Down
60 changes: 38 additions & 22 deletions tests/ui/redundant_type_annotations.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,8 +18,15 @@ fn plus_one<T: std::ops::Add<u8, Output = T>>(val: T) -> T {
val + 1
}

#[derive(Default)]
struct Slice {
inner: u32,
}

#[derive(Default)]
struct Pie {
inner: u32,
inner_struct: Slice,
}

enum Pizza {
Expand All @@ -32,7 +39,7 @@ fn return_a_string() -> String {
}

fn return_a_struct() -> Pie {
Pie { inner: 5 }
Pie::default()
}

fn return_an_enum() -> Pizza {
Expand All @@ -48,20 +55,32 @@ impl Pie {
self.inner
}

fn return_a_ref(&self) -> &u32 {
&self.inner
}

fn return_a_ref_to_struct(&self) -> &Slice {
&self.inner_struct
}

fn associated_return_an_int() -> u32 {
5
}

fn new() -> Self {
Self { inner: 5 }
Self::default()
}

fn associated_return_a_string() -> String {
String::from("")
}

fn test_method_call(&self) {
let v: u32 = self.return_an_int(); // Should lint
// Everything here should be lint

let v: u32 = self.return_an_int();
let v: &u32 = self.return_a_ref();
let v: &Slice = self.return_a_ref_to_struct();
}
}

Expand All @@ -72,21 +91,24 @@ fn test_generics() {
// The type annotation is needed to determine the topic
let _c: Cake<u8> = make_cake();

// This should lint (doesn't)
// This could be lint, but currently doesn't
let _c: Cake<u8> = make_cake::<u8>();

// This should lint (doesn't)
// This could be lint, but currently doesn't
let _c: u8 = make_something::<u8>();

// This should lint (doesn't)
// This could be lint, but currently doesn't
let _c: u8 = plus_one(5_u8);

// Annotation needed otherwise T is i32
let _c: u8 = plus_one(5);

// This could be lint, but currently doesn't
let _return: String = String::from("test");
}

fn test_non_locals() {
// This shouldn't lint
// This shouldn't be lint
fn _arg(x: u32) -> u32 {
x
}
Expand All @@ -96,27 +118,27 @@ fn test_non_locals() {
}

fn test_complex_types() {
// Shouldn't lint, since the literal will be i32 otherwise
// Shouldn't be lint, since the literal will be i32 otherwise
let _u8: u8 = 128;

// Should lint (doesn't)
// This could be lint, but currently doesn't
let _tuple_i32: (i32, i32) = (12, 13);

// Shouldn't lint, since the tuple will be i32 otherwise
// Shouldn't be lint, since the tuple will be i32 otherwise
let _tuple_u32: (u32, u32) = (1, 2);

// Should lint, since the type is determined by the init value (doesn't)
// Should be lint, since the type is determined by the init value, but currently doesn't
let _tuple_u32: (u32, u32) = (3_u32, 4_u32);

// Should lint (doesn't)
// This could be lint, but currently doesn't
let _array: [i32; 3] = [5, 6, 7];

// Shouldn't lint
// Shouldn't be lint
let _array: [u32; 2] = [8, 9];
}

fn test_functions() {
// Everything here should lint
// Everything here should be lint

let _return: String = return_a_string();

Expand All @@ -132,29 +154,23 @@ fn test_functions() {

let _return: u32 = new_pie.return_an_int();

let _return: String = String::from("test");

let _return: u32 = Pie::associated_return_an_int();

let _return: String = Pie::associated_return_a_string();
}

fn test_simple_types() {
// Everything here should be lint

let _var: u32 = u32::MAX;

// Should lint
let _var: u32 = 5_u32;

// Should lint
let _var: &str = "test";

// Should lint
let _var: &[u8] = b"test";

// Should lint
let _var: bool = false;
}

fn main() {}

// TODO: test refs
46 changes: 29 additions & 17 deletions tests/ui/redundant_type_annotations.stderr
View file
Original file line number Diff line number Diff line change
@@ -1,94 +1,106 @@
error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:64:9
--> $DIR/redundant_type_annotations.rs:81:9
|
LL | let v: u32 = self.return_an_int(); // Should lint
LL | let v: u32 = self.return_an_int();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `-D clippy::redundant-type-annotations` implied by `-D warnings`

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:121:5
--> $DIR/redundant_type_annotations.rs:82:9
|
LL | let v: &u32 = self.return_a_ref();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:83:9
|
LL | let v: &Slice = self.return_a_ref_to_struct();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:143:5
|
LL | let _return: String = return_a_string();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:123:5
--> $DIR/redundant_type_annotations.rs:145:5
|
LL | let _return: Pie = return_a_struct();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:125:5
--> $DIR/redundant_type_annotations.rs:147:5
|
LL | let _return: Pizza = return_an_enum();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:127:5
--> $DIR/redundant_type_annotations.rs:149:5
|
LL | let _return: u32 = return_an_int();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:129:5
--> $DIR/redundant_type_annotations.rs:151:5
|
LL | let _return: String = String::new();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:131:5
--> $DIR/redundant_type_annotations.rs:153:5
|
LL | let new_pie: Pie = Pie::new();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:133:5
--> $DIR/redundant_type_annotations.rs:155:5
|
LL | let _return: u32 = new_pie.return_an_int();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:137:5
--> $DIR/redundant_type_annotations.rs:157:5
|
LL | let _return: u32 = Pie::associated_return_an_int();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:139:5
--> $DIR/redundant_type_annotations.rs:159:5
|
LL | let _return: String = Pie::associated_return_a_string();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:143:5
--> $DIR/redundant_type_annotations.rs:165:5
|
LL | let _var: u32 = u32::MAX;
| ^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:146:5
--> $DIR/redundant_type_annotations.rs:167:5
|
LL | let _var: u32 = 5_u32;
| ^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:149:5
--> $DIR/redundant_type_annotations.rs:169:5
|
LL | let _var: &str = "test";
| ^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:152:5
--> $DIR/redundant_type_annotations.rs:171:5
|
LL | let _var: &[u8] = b"test";
| ^^^^^^^^^^^^^^^^^^^^^^^^^^

error: redundant type annotation
--> $DIR/redundant_type_annotations.rs:155:5
--> $DIR/redundant_type_annotations.rs:173:5
|
LL | let _var: bool = false;
| ^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 15 previous errors
error: aborting due to 17 previous errors

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