Fix unused_variables in tests

13 files changed, 122 insertions, 104 deletions

diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs
index a5c6983f95c..9905d522146 100644
--- a/crates/hir-ty/src/mir/lower.rs
+++ b/crates/hir-ty/src/mir/lower.rs
@@ -1774,13 +1774,14 @@ impl<'ctx> MirLowerCtx<'ctx> {
                         }
                     }
                 }
-                hir_def::hir::Statement::Expr { expr, has_semi: _ } => {
+                &hir_def::hir::Statement::Expr { expr, has_semi: _ } => {
                     let scope2 = self.push_drop_scope();
-                    let Some((_, c)) = self.lower_expr_as_place(current, *expr, true)? else {
+                    let Some((p, c)) = self.lower_expr_as_place(current, expr, true)? else {
                         scope2.pop_assume_dropped(self);
                         scope.pop_assume_dropped(self);
                         return Ok(None);
                     };
+                    self.push_fake_read(c, p, expr.into());
                     current = scope2.pop_and_drop(self, c);
                 }
             }
diff --git a/crates/ide-diagnostics/src/handlers/field_shorthand.rs b/crates/ide-diagnostics/src/handlers/field_shorthand.rs
index 3b69640af9b..9ed8199ae4d 100644
--- a/crates/ide-diagnostics/src/handlers/field_shorthand.rs
+++ b/crates/ide-diagnostics/src/handlers/field_shorthand.rs
@@ -166,7 +166,7 @@ fn main() {
         check_diagnostics(
             r#"
 struct A { a: &'static str }
-fn f(a: A) { let A { a: hello } = a; }
+fn f(a: A) { let A { a: _hello } = a; }
 "#,
         );
         check_diagnostics(
@@ -181,12 +181,14 @@ fn f(a: A) { let A { 0: 0 } = a; }
 struct A { a: &'static str }
 fn f(a: A) {
     let A { a$0: a } = a;
+    _ = a;
 }
 "#,
             r#"
 struct A { a: &'static str }
 fn f(a: A) {
     let A { a } = a;
+    _ = a;
 }
 "#,
         );
@@ -196,12 +198,14 @@ fn f(a: A) {
 struct A { a: &'static str, b: &'static str }
 fn f(a: A) {
     let A { a$0: a, b } = a;
+    _ = (a, b);
 }
 "#,
             r#"
 struct A { a: &'static str, b: &'static str }
 fn f(a: A) {
     let A { a, b } = a;
+    _ = (a, b);
 }
 "#,
         );
diff --git a/crates/ide-diagnostics/src/handlers/incorrect_case.rs b/crates/ide-diagnostics/src/handlers/incorrect_case.rs
index 235062bf531..7824011db67 100644
--- a/crates/ide-diagnostics/src/handlers/incorrect_case.rs
+++ b/crates/ide-diagnostics/src/handlers/incorrect_case.rs
@@ -175,10 +175,10 @@ fn NonSnakeCaseName() {}
     fn incorrect_function_params() {
         check_diagnostics(
             r#"
-fn foo(SomeParam: u8) {}
+fn foo(SomeParam: u8) { _ = SomeParam; }
     // ^^^^^^^^^ 💡 warn: Parameter `SomeParam` should have snake_case name, e.g. `some_param`
 
-fn foo2(ok_param: &str, CAPS_PARAM: u8) {}
+fn foo2(ok_param: &str, CAPS_PARAM: u8) { _ = (ok_param, CAPS_PARAM); }
                      // ^^^^^^^^^^ 💡 warn: Parameter `CAPS_PARAM` should have snake_case name, e.g. `caps_param`
 "#,
         );
@@ -188,6 +188,7 @@ fn foo2(ok_param: &str, CAPS_PARAM: u8) {}
     fn incorrect_variable_names() {
         check_diagnostics(
             r#"
+#[allow(unused)]
 fn foo() {
     let SOME_VALUE = 10;
      // ^^^^^^^^^^ 💡 warn: Variable `SOME_VALUE` should have snake_case name, e.g. `some_value`
@@ -294,6 +295,7 @@ impl someStruct {
     // ^^^^^^^^ 💡 warn: Function `SomeFunc` should have snake_case name, e.g. `some_func`
         let WHY_VAR_IS_CAPS = 10;
          // ^^^^^^^^^^^^^^^ 💡 warn: Variable `WHY_VAR_IS_CAPS` should have snake_case name, e.g. `why_var_is_caps`
+        _ = WHY_VAR_IS_CAPS;
     }
 }
 "#,
@@ -306,6 +308,7 @@ impl someStruct {
             r#"
 enum Option { Some, None }
 
+#[allow(unused)]
 fn main() {
     match Option::None {
         None => (),
@@ -322,6 +325,7 @@ fn main() {
             r#"
 enum Option { Some, None }
 
+#[allow(unused)]
 fn main() {
     match Option::None {
         SOME_VAR @ None => (),
@@ -349,7 +353,9 @@ enum E {
 }
 
 mod F {
-    fn CheckItWorksWithCrateAttr(BAD_NAME_HI: u8) {}
+    fn CheckItWorksWithCrateAttr(BAD_NAME_HI: u8) {
+        _ = BAD_NAME_HI;
+    }
 }
     "#,
         );
@@ -395,7 +401,7 @@ fn qualify() {
 
     #[test] // Issue #8809.
     fn parenthesized_parameter() {
-        check_diagnostics(r#"fn f((O): _) {}"#)
+        check_diagnostics(r#"fn f((O): _) { _ = O; }"#)
     }
 
     #[test]
@@ -472,7 +478,9 @@ mod CheckBadStyle {
 
 mod F {
     #![allow(non_snake_case)]
-    fn CheckItWorksWithModAttr(BAD_NAME_HI: u8) {}
+    fn CheckItWorksWithModAttr(BAD_NAME_HI: u8) {
+        _ = BAD_NAME_HI;
+    }
 }
 
 #[allow(non_snake_case, non_camel_case_types)]
diff --git a/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs b/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs
index 8265e0b1c11..ede9858c726 100644
--- a/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs
+++ b/crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs
@@ -131,7 +131,7 @@ fn f() { zero(); }
     fn simple_free_fn_one() {
         check_diagnostics(
             r#"
-fn one(arg: u8) {}
+fn one(_arg: u8) {}
 fn f() { one(); }
           //^^ error: expected 1 argument, found 0
 "#,
@@ -139,7 +139,7 @@ fn f() { one(); }
 
         check_diagnostics(
             r#"
-fn one(arg: u8) {}
+fn one(_arg: u8) {}
 fn f() { one(1); }
 "#,
         );
@@ -176,7 +176,7 @@ fn f() {
         check_diagnostics(
             r#"
 struct S;
-impl S { fn method(&self, arg: u8) {} }
+impl S { fn method(&self, _arg: u8) {} }
 
             fn f() {
                 S.method();
@@ -187,7 +187,7 @@ impl S { fn method(&self, arg: u8) {} }
         check_diagnostics(
             r#"
 struct S;
-impl S { fn method(&self, arg: u8) {} }
+impl S { fn method(&self, _arg: u8) {} }
 
 fn f() {
     S::method(&S, 0);
@@ -335,8 +335,8 @@ struct S;
 
 impl S {
     fn method(#[cfg(NEVER)] self) {}
-    fn method2(#[cfg(NEVER)] self, arg: u8) {}
-    fn method3(self, #[cfg(NEVER)] arg: u8) {}
+    fn method2(#[cfg(NEVER)] self, _arg: u8) {}
+    fn method3(self, #[cfg(NEVER)] _arg: u8) {}
 }
 
 extern "C" {
@@ -365,8 +365,8 @@ fn main() {
             r#"
 #[rustc_legacy_const_generics(1, 3)]
 fn mixed<const N1: &'static str, const N2: bool>(
-    a: u8,
-    b: i8,
+    _a: u8,
+    _b: i8,
 ) {}
 
 fn f() {
@@ -376,8 +376,8 @@ fn f() {
 
 #[rustc_legacy_const_generics(1, 3)]
 fn b<const N1: u8, const N2: u8>(
-    a: u8,
-    b: u8,
+    _a: u8,
+    _b: u8,
 ) {}
 
 fn g() {
@@ -403,7 +403,7 @@ fn f(
   // ^^ error: this pattern has 0 fields, but the corresponding tuple struct has 2 fields
     S(e, f, .., g, d): S
   //        ^^^^^^^^^ error: this pattern has 4 fields, but the corresponding tuple struct has 2 fields
-) {}
+) { _ = (a, b, c, d, e, f, g); }
 "#,
         )
     }
diff --git a/crates/ide-diagnostics/src/handlers/missing_fields.rs b/crates/ide-diagnostics/src/handlers/missing_fields.rs
index acc31cd117a..3178c7fa2bc 100644
--- a/crates/ide-diagnostics/src/handlers/missing_fields.rs
+++ b/crates/ide-diagnostics/src/handlers/missing_fields.rs
@@ -290,6 +290,7 @@ fn x(a: S) {
 struct S { s: u32 }
 fn x(a: S) {
     let S { ref s } = a;
+    _ = s;
 }
 ",
         )
@@ -626,7 +627,7 @@ struct TestStruct { one: i32, two: i64 }
 
 fn test_fn() {
     let one = 1;
-    let s = TestStruct{ one, two: 2 };
+    let _s = TestStruct{ one, two: 2 };
 }
         "#,
         );
diff --git a/crates/ide-diagnostics/src/handlers/missing_match_arms.rs b/crates/ide-diagnostics/src/handlers/missing_match_arms.rs
index 06b03d3d198..84267d3d906 100644
--- a/crates/ide-diagnostics/src/handlers/missing_match_arms.rs
+++ b/crates/ide-diagnostics/src/handlers/missing_match_arms.rs
@@ -19,6 +19,7 @@ pub(crate) fn missing_match_arms(
 mod tests {
     use crate::tests::check_diagnostics;
 
+    #[track_caller]
     fn check_diagnostics_no_bails(ra_fixture: &str) {
         cov_mark::check_count!(validate_match_bailed_out, 0);
         crate::tests::check_diagnostics(ra_fixture)
@@ -564,6 +565,7 @@ fn bang(never: !) {
             r#"
 enum Option<T> { Some(T), None }
 
+#[allow(unused)]
 fn main() {
     // `Never` is deliberately not defined so that it's an uninferred type.
     match Option::<Never>::None {
@@ -719,7 +721,7 @@ fn main() {
             r#"
 struct S { a: char}
 fn main(v: S) {
-    match v { S{ a }      => {} }
+    match v { S{ a }      => { _ = a; } }
     match v { S{ a: _x }  => {} }
     match v { S{ a: 'a' } => {} }
     match v { S{..}       => {} }
@@ -901,7 +903,7 @@ enum E{ A, B }
 fn foo() {
     match &E::A {
         E::A => {}
-        x => {}
+        _x => {}
     }
 }",
         );
diff --git a/crates/ide-diagnostics/src/handlers/missing_unsafe.rs b/crates/ide-diagnostics/src/handlers/missing_unsafe.rs
index 70b26009bae..0f695b2745a 100644
--- a/crates/ide-diagnostics/src/handlers/missing_unsafe.rs
+++ b/crates/ide-diagnostics/src/handlers/missing_unsafe.rs
@@ -100,9 +100,9 @@ mod tests {
             r#"
 fn main() {
     let x = &5 as *const usize;
-    unsafe { let y = *x; }
-    let z = *x;
-}         //^^💡 error: this operation is unsafe and requires an unsafe function or block
+    unsafe { let _y = *x; }
+    let _z = *x;
+}          //^^💡 error: this operation is unsafe and requires an unsafe function or block
 "#,
         )
     }
@@ -116,13 +116,13 @@ struct HasUnsafe;
 impl HasUnsafe {
     unsafe fn unsafe_fn(&self) {
         let x = &5 as *const usize;
-        let y = *x;
+        let _y = *x;
     }
 }
 
 unsafe fn unsafe_fn() {
     let x = &5 as *const usize;
-    let y = *x;
+    let _y = *x;
 }
 
 fn main() {
@@ -152,10 +152,10 @@ struct Ty {
 static mut STATIC_MUT: Ty = Ty { a: 0 };
 
 fn main() {
-    let x = STATIC_MUT.a;
-          //^^^^^^^^^^💡 error: this operation is unsafe and requires an unsafe function or block
+    let _x = STATIC_MUT.a;
+           //^^^^^^^^^^💡 error: this operation is unsafe and requires an unsafe function or block
     unsafe {
-        let x = STATIC_MUT.a;
+        let _x = STATIC_MUT.a;
     }
 }
 "#,
@@ -187,13 +187,13 @@ fn main() {
             r#"
 fn main() {
     let x = &5 as *const usize;
-    let z = *x$0;
+    let _z = *x$0;
 }
 "#,
             r#"
 fn main() {
     let x = &5 as *const usize;
-    let z = unsafe { *x };
+    let _z = unsafe { *x };
 }
 "#,
         );
@@ -231,7 +231,7 @@ struct S(usize);
 impl S {
     unsafe fn func(&self) {
         let x = &self.0 as *const usize;
-        let z = *x;
+        let _z = *x;
     }
 }
 fn main() {
@@ -244,7 +244,7 @@ struct S(usize);
 impl S {
     unsafe fn func(&self) {
         let x = &self.0 as *const usize;
-        let z = *x;
+        let _z = *x;
     }
 }
 fn main() {
@@ -267,7 +267,7 @@ struct Ty {
 static mut STATIC_MUT: Ty = Ty { a: 0 };
 
 fn main() {
-    let x = STATIC_MUT$0.a;
+    let _x = STATIC_MUT$0.a;
 }
 "#,
             r#"
@@ -278,7 +278,7 @@ struct Ty {
 static mut STATIC_MUT: Ty = Ty { a: 0 };
 
 fn main() {
-    let x = unsafe { STATIC_MUT.a };
+    let _x = unsafe { STATIC_MUT.a };
 }
 "#,
         )
@@ -382,16 +382,16 @@ fn main() {
 static mut STATIC_MUT: u8 = 0;
 
 fn main() {
-    let x;
-    x = STATIC_MUT$0;
+    let _x;
+    _x = STATIC_MUT$0;
 }
 "#,
             r#"
 static mut STATIC_MUT: u8 = 0;
 
 fn main() {
-    let x;
-    x = unsafe { STATIC_MUT };
+    let _x;
+    _x = unsafe { STATIC_MUT };
 }
 "#,
         )
@@ -405,14 +405,14 @@ fn main() {
 static mut STATIC_MUT: u8 = 0;
 
 fn main() {
-    let x = STATIC_MUT$0 + 1;
+    let _x = STATIC_MUT$0 + 1;
 }
 "#,
             r#"
 static mut STATIC_MUT: u8 = 0;
 
 fn main() {
-    let x = unsafe { STATIC_MUT } + 1;
+    let _x = unsafe { STATIC_MUT } + 1;
 }
 "#,
         )
@@ -425,14 +425,14 @@ fn main() {
 static mut STATIC_MUT: u8 = 0;
 
 fn main() {
-    let x = &STATIC_MUT$0;
+    let _x = &STATIC_MUT$0;
 }
 "#,
             r#"
 static mut STATIC_MUT: u8 = 0;
 
 fn main() {
-    let x = unsafe { &STATIC_MUT };
+    let _x = unsafe { &STATIC_MUT };
 }
 "#,
         )
@@ -445,14 +445,14 @@ fn main() {
 static mut STATIC_MUT: u8 = 0;
 
 fn main() {
-    let x = &&STATIC_MUT$0;
+    let _x = &&STATIC_MUT$0;
 }
 "#,
             r#"
 static mut STATIC_MUT: u8 = 0;
 
 fn main() {
-    let x = unsafe { &&STATIC_MUT };
+    let _x = unsafe { &&STATIC_MUT };
 }
 "#,
         )
diff --git a/crates/ide-diagnostics/src/handlers/moved_out_of_ref.rs b/crates/ide-diagnostics/src/handlers/moved_out_of_ref.rs
index 3aa4aa97026..20175b3fd53 100644
--- a/crates/ide-diagnostics/src/handlers/moved_out_of_ref.rs
+++ b/crates/ide-diagnostics/src/handlers/moved_out_of_ref.rs
@@ -29,6 +29,7 @@ fn main() {
     let a = &X;
     let b = *a;
       //^ error: cannot move `X` out of reference
+    _ = b;
 }
 "#,
         );
@@ -46,6 +47,7 @@ fn main() {
     let b = a.0;
       //^ error: cannot move `X` out of reference
     let y = a.1;
+    _ = (b, y);
 }
 "#,
         );
@@ -59,8 +61,8 @@ fn main() {
 struct X;
 fn main() {
     static S: X = X;
-    let s = S;
-      //^ error: cannot move `X` out of reference
+    let _s = S;
+      //^^ error: cannot move `X` out of reference
 }
 "#,
         );
@@ -165,7 +167,7 @@ enum X {
 
 fn main() {
     let x = &X::Bar;
-    let c = || match *x {
+    let _c = || match *x {
         X::Foo(t) => t,
         _ => 5,
     };
diff --git a/crates/ide-diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs b/crates/ide-diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
index 083ef3e8dc1..d15233d15c2 100644
--- a/crates/ide-diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
+++ b/crates/ide-diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
@@ -74,8 +74,8 @@ mod tests {
             r#"
 //- minicore: iterators
 fn foo() {
-    let m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
-}         //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 weak: replace filter_map(..).next() with find_map(..)
+    let _m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
+}          //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 weak: replace filter_map(..).next() with find_map(..)
 "#,
         );
     }
@@ -117,7 +117,7 @@ fn foo() {
 fn foo() {
     let mut m = core::iter::repeat(())
         .filter_map(|()| Some(92));
-    let n = m.next();
+    let _n = m.next();
 }
 "#,
         );
@@ -148,22 +148,22 @@ fn foo() {
 
 fn foo() {
     #[allow(clippy::filter_map_next)]
-    let m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
+    let _m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
 }
 
 #[deny(clippy::filter_map_next)]
 fn foo() {
-    let m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
-}         //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 error: replace filter_map(..).next() with find_map(..)
+    let _m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
+}          //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 error: replace filter_map(..).next() with find_map(..)
 
 fn foo() {
-    let m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
-}         //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 weak: replace filter_map(..).next() with find_map(..)
+    let _m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
+}          //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 weak: replace filter_map(..).next() with find_map(..)
 
 #[warn(clippy::filter_map_next)]
 fn foo() {
-    let m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
-}         //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 warn: replace filter_map(..).next() with find_map(..)
+    let _m = core::iter::repeat(()).filter_map(|()| Some(92)).next();
+}          //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 💡 warn: replace filter_map(..).next() with find_map(..)
 
 "#,
         );
diff --git a/crates/ide-diagnostics/src/handlers/type_mismatch.rs b/crates/ide-diagnostics/src/handlers/type_mismatch.rs
index 15bd28c00df..1f400bb42dd 100644
--- a/crates/ide-diagnostics/src/handlers/type_mismatch.rs
+++ b/crates/ide-diagnostics/src/handlers/type_mismatch.rs
@@ -205,7 +205,7 @@ fn main() {
     test(123);
        //^^^ 💡 error: expected &i32, found i32
 }
-fn test(arg: &i32) {}
+fn test(_arg: &i32) {}
 "#,
         );
     }
@@ -217,13 +217,13 @@ fn test(arg: &i32) {}
 fn main() {
     test(123$0);
 }
-fn test(arg: &i32) {}
+fn test(_arg: &i32) {}
             "#,
             r#"
 fn main() {
     test(&123);
 }
-fn test(arg: &i32) {}
+fn test(_arg: &i32) {}
             "#,
         );
     }
@@ -235,13 +235,13 @@ fn test(arg: &i32) {}
 fn main() {
     test($0123);
 }
-fn test(arg: &mut i32) {}
+fn test(_arg: &mut i32) {}
             "#,
             r#"
 fn main() {
     test(&mut 123);
 }
-fn test(arg: &mut i32) {}
+fn test(_arg: &mut i32) {}
             "#,
         );
     }
@@ -254,13 +254,13 @@ fn test(arg: &mut i32) {}
 fn main() {
     test($0[1, 2, 3]);
 }
-fn test(arg: &[i32]) {}
+fn test(_arg: &[i32]) {}
             "#,
             r#"
 fn main() {
     test(&[1, 2, 3]);
 }
-fn test(arg: &[i32]) {}
+fn test(_arg: &[i32]) {}
             "#,
         );
     }
@@ -279,7 +279,7 @@ impl core::ops::Deref for Foo {
 fn main() {
     test($0Foo);
 }
-fn test(arg: &Bar) {}
+fn test(_arg: &Bar) {}
             "#,
             r#"
 struct Foo;
@@ -291,7 +291,7 @@ impl core::ops::Deref for Foo {
 fn main() {
     test(&Foo);
 }
-fn test(arg: &Bar) {}
+fn test(_arg: &Bar) {}
             "#,
         );
     }
@@ -305,7 +305,7 @@ fn main() {
 }
 struct Test;
 impl Test {
-    fn call_by_ref(&self, arg: &i32) {}
+    fn call_by_ref(&self, _arg: &i32) {}
 }
             "#,
             r#"
@@ -314,7 +314,7 @@ fn main() {
 }
 struct Test;
 impl Test {
-    fn call_by_ref(&self, arg: &i32) {}
+    fn call_by_ref(&self, _arg: &i32) {}
 }
             "#,
         );
@@ -345,7 +345,7 @@ macro_rules! thousand {
         1000_u64
     };
 }
-fn test(foo: &u64) {}
+fn test(_foo: &u64) {}
 fn main() {
     test($0thousand!());
 }
@@ -356,7 +356,7 @@ macro_rules! thousand {
         1000_u64
     };
 }
-fn test(foo: &u64) {}
+fn test(_foo: &u64) {}
 fn main() {
     test(&thousand!());
 }
@@ -369,12 +369,12 @@ fn main() {
         check_fix(
             r#"
 fn main() {
-    let test: &mut i32 = $0123;
+    let _test: &mut i32 = $0123;
 }
             "#,
             r#"
 fn main() {
-    let test: &mut i32 = &mut 123;
+    let _test: &mut i32 = &mut 123;
 }
             "#,
         );
@@ -411,7 +411,7 @@ fn div(x: i32, y: i32) -> Option<i32> {
             fn f<const N: u64>() -> Rate<N> { // FIXME: add some error
                 loop {}
             }
-            fn run(t: Rate<5>) {
+            fn run(_t: Rate<5>) {
             }
             fn main() {
                 run(f()) // FIXME: remove this error
@@ -426,7 +426,7 @@ fn div(x: i32, y: i32) -> Option<i32> {
         check_diagnostics(
             r#"
             pub struct Rate<T, const NOM: u32, const DENOM: u32>(T);
-            fn run(t: Rate<u32, 1, 1>) {
+            fn run(_t: Rate<u32, 1, 1>) {
             }
             fn main() {
                 run(Rate::<_, _, _>(5));
@@ -650,7 +650,7 @@ fn h() {
             r#"
 struct X<T>(T);
 
-fn foo(x: X<Unknown>) {}
+fn foo(_x: X<Unknown>) {}
 fn test1() {
     // Unknown might be `i32`, so we should not emit type mismatch here.
     foo(X(42));
diff --git a/crates/ide-diagnostics/src/handlers/typed_hole.rs b/crates/ide-diagnostics/src/handlers/typed_hole.rs
index 4af67227115..4e215a89d79 100644
--- a/crates/ide-diagnostics/src/handlers/typed_hole.rs
+++ b/crates/ide-diagnostics/src/handlers/typed_hole.rs
@@ -142,8 +142,8 @@ fn t<T>() -> T { loop {} }
         check_diagnostics(
             r#"
 fn main() {
-    let x = [(); _];
-    let y: [(); 10] = [(); _];
+    let _x = [(); _];
+    let _y: [(); 10] = [(); _];
     _ = 0;
     (_,) = (1,);
 }
diff --git a/crates/ide/src/inlay_hints/chaining.rs b/crates/ide/src/inlay_hints/chaining.rs
index 12e46c0f883..4152e606755 100644
--- a/crates/ide/src/inlay_hints/chaining.rs
+++ b/crates/ide/src/inlay_hints/chaining.rs
@@ -484,7 +484,7 @@ fn main() {
                                         file_id: FileId(
                                             1,
                                         ),
-                                        range: 10739..10747,
+                                        range: 10752..10760,
                                     },
                                 ),
                                 tooltip: "",
@@ -497,7 +497,7 @@ fn main() {
                                         file_id: FileId(
                                             1,
                                         ),
-                                        range: 10771..10775,
+                                        range: 10784..10788,
                                     },
                                 ),
                                 tooltip: "",
@@ -522,7 +522,7 @@ fn main() {
                                         file_id: FileId(
                                             1,
                                         ),
-                                        range: 10739..10747,
+                                        range: 10752..10760,
                                     },
                                 ),
                                 tooltip: "",
@@ -535,7 +535,7 @@ fn main() {
                                         file_id: FileId(
                                             1,
                                         ),
-                                        range: 10771..10775,
+                                        range: 10784..10788,
                                     },
                                 ),
                                 tooltip: "",
@@ -560,7 +560,7 @@ fn main() {
                                         file_id: FileId(
                                             1,
                                         ),
-                                        range: 10739..10747,
+                                        range: 10752..10760,
                                     },
                                 ),
                                 tooltip: "",
@@ -573,7 +573,7 @@ fn main() {
                                         file_id: FileId(
                                             1,
                                         ),
-                                        range: 10771..10775,
+                                        range: 10784..10788,
                                     },
                                 ),
                                 tooltip: "",
diff --git a/crates/test-utils/src/minicore.rs b/crates/test-utils/src/minicore.rs
index 573f56b003a..cc41d87f5d9 100644
--- a/crates/test-utils/src/minicore.rs
+++ b/crates/test-utils/src/minicore.rs
@@ -489,7 +489,7 @@ pub mod ops {
             I: SliceIndex<[T]>,
         {
             type Output = I::Output;
-            fn index(&self, index: I) -> &I::Output {
+            fn index(&self, _index: I) -> &I::Output {
                 loop {}
             }
         }
@@ -497,7 +497,7 @@ pub mod ops {
         where
             I: SliceIndex<[T]>,
         {
-            fn index_mut(&mut self, index: I) -> &mut I::Output {
+            fn index_mut(&mut self, _index: I) -> &mut I::Output {
                 loop {}
             }
         }
@@ -507,7 +507,7 @@ pub mod ops {
             I: SliceIndex<[T]>,
         {
             type Output = I::Output;
-            fn index(&self, index: I) -> &I::Output {
+            fn index(&self, _index: I) -> &I::Output {
                 loop {}
             }
         }
@@ -515,7 +515,7 @@ pub mod ops {
         where
             I: SliceIndex<[T]>,
         {
-            fn index_mut(&mut self, index: I) -> &mut I::Output {
+            fn index_mut(&mut self, _index: I) -> &mut I::Output {
                 loop {}
             }
         }
@@ -863,17 +863,17 @@ pub mod fmt {
     pub struct DebugTuple;
     pub struct DebugStruct;
     impl Formatter<'_> {
-        pub fn debug_tuple(&mut self, name: &str) -> DebugTuple {
+        pub fn debug_tuple(&mut self, _name: &str) -> DebugTuple {
             DebugTuple
         }
 
-        pub fn debug_struct(&mut self, name: &str) -> DebugStruct {
+        pub fn debug_struct(&mut self, _name: &str) -> DebugStruct {
             DebugStruct
         }
     }
 
     impl DebugTuple {
-        pub fn field(&mut self, value: &dyn Debug) -> &mut Self {
+        pub fn field(&mut self, _value: &dyn Debug) -> &mut Self {
             self
         }
 
@@ -883,7 +883,7 @@ pub mod fmt {
     }
 
     impl DebugStruct {
-        pub fn field(&mut self, name: &str, value: &dyn Debug) -> &mut Self {
+        pub fn field(&mut self, _name: &str, _value: &dyn Debug) -> &mut Self {
             self
         }
 
@@ -996,7 +996,7 @@ pub mod fmt {
         ($($t:ty)*) => {
             $(
                 impl const Debug for $t {
-                    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+                    fn fmt(&self, _f: &mut Formatter<'_>) -> Result {
                         Ok(())
                     }
                 }
@@ -1012,7 +1012,7 @@ pub mod fmt {
     }
 
     impl<T: Debug> Debug for [T] {
-        fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        fn fmt(&self, _f: &mut Formatter<'_>) -> Result {
             Ok(())
         }
     }
@@ -1062,7 +1062,7 @@ pub mod option {
             }
         }
 
-        pub fn and<U>(self, optb: Option<U>) -> Option<U> {
+        pub fn and<U>(self, _optb: Option<U>) -> Option<U> {
             loop {}
         }
         pub fn unwrap_or(self, default: T) -> T {
@@ -1080,25 +1080,25 @@ pub mod option {
         }
         // endregion:result
         // region:fn
-        pub fn and_then<U, F>(self, f: F) -> Option<U>
+        pub fn and_then<U, F>(self, _f: F) -> Option<U>
         where
             F: FnOnce(T) -> Option<U>,
         {
             loop {}
         }
-        pub fn unwrap_or_else<F>(self, f: F) -> T
+        pub fn unwrap_or_else<F>(self, _f: F) -> T
         where
             F: FnOnce() -> T,
         {
             loop {}
         }
-        pub fn map_or<U, F>(self, default: U, f: F) -> U
+        pub fn map_or<U, F>(self, _default: U, _f: F) -> U
         where
             F: FnOnce(T) -> U,
         {
             loop {}
         }
-        pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U
+        pub fn map_or_else<U, D, F>(self, _default: D, _f: F) -> U
         where
             D: FnOnce() -> U,
             F: FnOnce(T) -> U,
@@ -1129,7 +1129,7 @@ pub mod pin {
         pointer: P,
     }
     impl<P> Pin<P> {
-        pub fn new(pointer: P) -> Pin<P> {
+        pub fn new(_pointer: P) -> Pin<P> {
             loop {}
         }
     }
@@ -1226,7 +1226,7 @@ pub mod iter {
 
     mod sources {
         mod repeat {
-            pub fn repeat<T>(elt: T) -> Repeat<T> {
+            pub fn repeat<T>(_elt: T) -> Repeat<T> {
                 loop {}
             }
 
@@ -1266,7 +1266,7 @@ pub mod iter {
                 fn take(self, n: usize) -> crate::iter::Take<Self> {
                     loop {}
                 }
-                fn filter_map<B, F>(self, f: F) -> crate::iter::FilterMap<Self, F>
+                fn filter_map<B, F>(self, _f: F) -> crate::iter::FilterMap<Self, F>
                 where
                     Self: Sized,
                     F: FnMut(Self::Item) -> Option<B>,
@@ -1337,7 +1337,7 @@ mod panic {
 
 mod panicking {
     #[lang = "panic_fmt"]
-    pub const fn panic_fmt(fmt: crate::fmt::Arguments<'_>) -> ! {
+    pub const fn panic_fmt(_fmt: crate::fmt::Arguments<'_>) -> ! {
         loop {}
     }
 }