Remove unused must_use

3 files changed, 174 insertions, 32 deletions

diff --git a/tests/ui/lint/unused/unused_attributes-must_use.fixed b/tests/ui/lint/unused/unused_attributes-must_use.fixed
new file mode 100644
index 00000000000..80d488296ea
--- /dev/null
+++ b/tests/ui/lint/unused/unused_attributes-must_use.fixed
@@ -0,0 +1,139 @@
+//@ run-rustfix
+
+#![allow(dead_code, path_statements)]
+#![deny(unused_attributes, unused_must_use)]
+#![feature(asm_experimental_arch, stmt_expr_attributes, trait_alias)]
+
+ //~ ERROR `#[must_use]` has no effect
+extern crate std as std2;
+
+ //~ ERROR `#[must_use]` has no effect
+mod test_mod {}
+
+ //~ ERROR `#[must_use]` has no effect
+use std::arch::global_asm;
+
+ //~ ERROR `#[must_use]` has no effect
+const CONST: usize = 4;
+ //~ ERROR `#[must_use]` has no effect
+#[no_mangle]
+static STATIC: usize = 4;
+
+#[must_use]
+struct X;
+
+#[must_use]
+enum Y {
+    Z,
+}
+
+#[must_use]
+union U {
+    unit: (),
+}
+
+ //~ ERROR `#[must_use]` has no effect
+impl U {
+    #[must_use]
+    fn method() -> i32 {
+        4
+    }
+}
+
+#[must_use]
+#[no_mangle]
+fn foo() -> i64 {
+    4
+}
+
+ //~ ERROR `#[must_use]` has no effect
+extern "Rust" {
+    #[link_name = "STATIC"]
+     //~ ERROR `#[must_use]` has no effect
+    static FOREIGN_STATIC: usize;
+
+    #[link_name = "foo"]
+    #[must_use]
+    fn foreign_foo() -> i64;
+}
+
+ //~ ERROR unused attribute
+global_asm!("");
+
+ //~ ERROR `#[must_use]` has no effect
+type UseMe = ();
+
+fn qux< T>(_: T) {} //~ ERROR `#[must_use]` has no effect
+
+#[must_use]
+trait Use {
+     //~ ERROR `#[must_use]` has no effect
+    const ASSOC_CONST: usize = 4;
+     //~ ERROR `#[must_use]` has no effect
+    type AssocTy;
+
+    #[must_use]
+    fn get_four(&self) -> usize {
+        4
+    }
+}
+
+ //~ ERROR `#[must_use]` has no effect
+impl Use for () {
+    type AssocTy = ();
+
+     //~ ERROR `#[must_use]` has no effect
+    fn get_four(&self) -> usize {
+        4
+    }
+}
+
+ //~ ERROR `#[must_use]` has no effect
+trait Alias = Use;
+
+ //~ ERROR `#[must_use]` has no effect
+macro_rules! cool_macro {
+    () => {
+        4
+    };
+}
+
+fn main() {
+     //~ ERROR `#[must_use]` has no effect
+    let x = || {};
+    x();
+
+    let x =  //~ ERROR `#[must_use]` has no effect
+    || {};
+    x();
+
+    let _ = X; //~ ERROR that must be used
+    let _ = Y::Z; //~ ERROR that must be used
+    let _ = U { unit: () }; //~ ERROR that must be used
+    let _ = U::method(); //~ ERROR that must be used
+    let _ = foo(); //~ ERROR that must be used
+
+    unsafe {
+        let _ = foreign_foo(); //~ ERROR that must be used
+    };
+
+    CONST;
+    STATIC;
+    unsafe { FOREIGN_STATIC };
+    cool_macro!();
+    qux(4);
+    let _ = ().get_four(); //~ ERROR that must be used
+
+    match Some(4) {
+         //~ ERROR `#[must_use]` has no effect
+        Some(res) => res,
+        None => 0,
+    };
+
+    struct PatternField {
+        foo: i32,
+    }
+    let s = PatternField {   foo: 123 }; //~ ERROR `#[must_use]` has no effect
+    let PatternField {  foo } = s; //~ ERROR `#[must_use]` has no effect
+    let _ = foo;
+}
diff --git a/tests/ui/lint/unused/unused_attributes-must_use.rs b/tests/ui/lint/unused/unused_attributes-must_use.rs
index 860fc5046d1..edefe8ed65e 100644
--- a/tests/ui/lint/unused/unused_attributes-must_use.rs
+++ b/tests/ui/lint/unused/unused_attributes-must_use.rs
@@ -1,3 +1,5 @@
+//@ run-rustfix
+
 #![allow(dead_code, path_statements)]
 #![deny(unused_attributes, unused_must_use)]
 #![feature(asm_experimental_arch, stmt_expr_attributes, trait_alias)]
@@ -133,4 +135,5 @@ fn main() {
     }
     let s = PatternField { #[must_use]  foo: 123 }; //~ ERROR `#[must_use]` has no effect
     let PatternField { #[must_use] foo } = s; //~ ERROR `#[must_use]` has no effect
+    let _ = foo;
 }
diff --git a/tests/ui/lint/unused/unused_attributes-must_use.stderr b/tests/ui/lint/unused/unused_attributes-must_use.stderr
index 862ffa42d80..27927cf37e9 100644
--- a/tests/ui/lint/unused/unused_attributes-must_use.stderr
+++ b/tests/ui/lint/unused/unused_attributes-must_use.stderr
@@ -1,154 +1,154 @@
 error: unused attribute `must_use`
-  --> $DIR/unused_attributes-must_use.rs:58:1
+  --> $DIR/unused_attributes-must_use.rs:60:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
    |
 note: the built-in attribute `must_use` will be ignored, since it's applied to the macro invocation `global_asm`
-  --> $DIR/unused_attributes-must_use.rs:59:1
+  --> $DIR/unused_attributes-must_use.rs:61:1
    |
 LL | global_asm!("");
    | ^^^^^^^^^^
 note: the lint level is defined here
-  --> $DIR/unused_attributes-must_use.rs:2:9
+  --> $DIR/unused_attributes-must_use.rs:4:9
    |
 LL | #![deny(unused_attributes, unused_must_use)]
    |         ^^^^^^^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to an extern crate
-  --> $DIR/unused_attributes-must_use.rs:5:1
+  --> $DIR/unused_attributes-must_use.rs:7:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a module
-  --> $DIR/unused_attributes-must_use.rs:8:1
+  --> $DIR/unused_attributes-must_use.rs:10:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a use
-  --> $DIR/unused_attributes-must_use.rs:11:1
+  --> $DIR/unused_attributes-must_use.rs:13:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a constant item
-  --> $DIR/unused_attributes-must_use.rs:14:1
+  --> $DIR/unused_attributes-must_use.rs:16:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a static item
-  --> $DIR/unused_attributes-must_use.rs:16:1
+  --> $DIR/unused_attributes-must_use.rs:18:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to an inherent implementation block
-  --> $DIR/unused_attributes-must_use.rs:33:1
+  --> $DIR/unused_attributes-must_use.rs:35:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a foreign module
-  --> $DIR/unused_attributes-must_use.rs:47:1
+  --> $DIR/unused_attributes-must_use.rs:49:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a type alias
-  --> $DIR/unused_attributes-must_use.rs:61:1
+  --> $DIR/unused_attributes-must_use.rs:63:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a type parameter
-  --> $DIR/unused_attributes-must_use.rs:64:8
+  --> $DIR/unused_attributes-must_use.rs:66:8
    |
 LL | fn qux<#[must_use] T>(_: T) {}
    |        ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to an trait implementation block
-  --> $DIR/unused_attributes-must_use.rs:79:1
+  --> $DIR/unused_attributes-must_use.rs:81:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a trait alias
-  --> $DIR/unused_attributes-must_use.rs:89:1
+  --> $DIR/unused_attributes-must_use.rs:91:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a macro def
-  --> $DIR/unused_attributes-must_use.rs:92:1
+  --> $DIR/unused_attributes-must_use.rs:94:1
    |
 LL | #[must_use]
    | ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a statement
-  --> $DIR/unused_attributes-must_use.rs:100:5
+  --> $DIR/unused_attributes-must_use.rs:102:5
    |
 LL |     #[must_use]
    |     ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a closure
-  --> $DIR/unused_attributes-must_use.rs:104:13
+  --> $DIR/unused_attributes-must_use.rs:106:13
    |
 LL |     let x = #[must_use]
    |             ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to an match arm
-  --> $DIR/unused_attributes-must_use.rs:126:9
+  --> $DIR/unused_attributes-must_use.rs:128:9
    |
 LL |         #[must_use]
    |         ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a struct field
-  --> $DIR/unused_attributes-must_use.rs:134:28
+  --> $DIR/unused_attributes-must_use.rs:136:28
    |
 LL |     let s = PatternField { #[must_use]  foo: 123 };
    |                            ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a pattern field
-  --> $DIR/unused_attributes-must_use.rs:135:24
+  --> $DIR/unused_attributes-must_use.rs:137:24
    |
 LL |     let PatternField { #[must_use] foo } = s;
    |                        ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to an associated const
-  --> $DIR/unused_attributes-must_use.rs:68:5
+  --> $DIR/unused_attributes-must_use.rs:70:5
    |
 LL |     #[must_use]
    |     ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to an associated type
-  --> $DIR/unused_attributes-must_use.rs:70:5
+  --> $DIR/unused_attributes-must_use.rs:72:5
    |
 LL |     #[must_use]
    |     ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a provided trait method
-  --> $DIR/unused_attributes-must_use.rs:83:5
+  --> $DIR/unused_attributes-must_use.rs:85:5
    |
 LL |     #[must_use]
    |     ^^^^^^^^^^^
 
 error: `#[must_use]` has no effect when applied to a foreign static item
-  --> $DIR/unused_attributes-must_use.rs:50:5
+  --> $DIR/unused_attributes-must_use.rs:52:5
    |
 LL |     #[must_use]
    |     ^^^^^^^^^^^
 
 error: unused `X` that must be used
-  --> $DIR/unused_attributes-must_use.rs:108:5
+  --> $DIR/unused_attributes-must_use.rs:110:5
    |
 LL |     X;
    |     ^
    |
 note: the lint level is defined here
-  --> $DIR/unused_attributes-must_use.rs:2:28
+  --> $DIR/unused_attributes-must_use.rs:4:28
    |
 LL | #![deny(unused_attributes, unused_must_use)]
    |                            ^^^^^^^^^^^^^^^
@@ -158,7 +158,7 @@ LL |     let _ = X;
    |     +++++++
 
 error: unused `Y` that must be used
-  --> $DIR/unused_attributes-must_use.rs:109:5
+  --> $DIR/unused_attributes-must_use.rs:111:5
    |
 LL |     Y::Z;
    |     ^^^^
@@ -169,7 +169,7 @@ LL |     let _ = Y::Z;
    |     +++++++
 
 error: unused `U` that must be used
-  --> $DIR/unused_attributes-must_use.rs:110:5
+  --> $DIR/unused_attributes-must_use.rs:112:5
    |
 LL |     U { unit: () };
    |     ^^^^^^^^^^^^^^
@@ -180,7 +180,7 @@ LL |     let _ = U { unit: () };
    |     +++++++
 
 error: unused return value of `U::method` that must be used
-  --> $DIR/unused_attributes-must_use.rs:111:5
+  --> $DIR/unused_attributes-must_use.rs:113:5
    |
 LL |     U::method();
    |     ^^^^^^^^^^^
@@ -191,7 +191,7 @@ LL |     let _ = U::method();
    |     +++++++
 
 error: unused return value of `foo` that must be used
-  --> $DIR/unused_attributes-must_use.rs:112:5
+  --> $DIR/unused_attributes-must_use.rs:114:5
    |
 LL |     foo();
    |     ^^^^^
@@ -202,7 +202,7 @@ LL |     let _ = foo();
    |     +++++++
 
 error: unused return value of `foreign_foo` that must be used
-  --> $DIR/unused_attributes-must_use.rs:115:9
+  --> $DIR/unused_attributes-must_use.rs:117:9
    |
 LL |         foreign_foo();
    |         ^^^^^^^^^^^^^
@@ -213,7 +213,7 @@ LL |         let _ = foreign_foo();
    |         +++++++
 
 error: unused return value of `Use::get_four` that must be used
-  --> $DIR/unused_attributes-must_use.rs:123:5
+  --> $DIR/unused_attributes-must_use.rs:125:5
    |
 LL |     ().get_four();
    |     ^^^^^^^^^^^^^