Fix unused_variables in tests

Author: HKalbasi

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);
                 }
             }

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);
 }
 "#,
         );

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)]

crates/ide-diagnostics/src/handlers/mismatched_arg_count.rs

@@ -131,15 +131,15 @@ 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
 "#,
         );
 
         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); }
 "#,
         )
     }

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 };
 }
         "#,
         );

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 => {}
     }
 }",
         );