wip

Author: JonathanBrouwer

compiler/rustc_attr_parsing/src/attributes/must_use.rs

@@ -5,7 +5,7 @@ use rustc_hir::{MethodKind, Target};
 use rustc_span::{Symbol, sym};
 
 use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
-use crate::context::MaybeWarn::{Allow, Warn};
+use crate::context::MaybeWarn::{Allow};
 use crate::context::{AcceptContext, AllowedTargets, Stage};
 use crate::parser::ArgParser;
 use crate::session_diagnostics;
@@ -15,21 +15,16 @@ impl<S: Stage> SingleAttributeParser<S> for MustUseParser {
     const PATH: &[Symbol] = &[sym::must_use];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowListWarnRest(&[
         Allow(Target::Fn),
         Allow(Target::Enum),
         Allow(Target::Struct),
         Allow(Target::Union),
         Allow(Target::Method(MethodKind::Trait { body: false })),
+        Allow(Target::Method(MethodKind::Trait { body: true })), // Sometimes not allowed, see check_attr
         Allow(Target::Method(MethodKind::Inherent)),
         Allow(Target::ForeignFn),
         Allow(Target::Trait),
-        Warn(Target::Method(MethodKind::Trait { body: true })),
-        Warn(Target::Crate),
-        Warn(Target::Mod),
-        Warn(Target::TyAlias),
-        Warn(Target::Impl { of_trait: false }),
-        Warn(Target::Impl { of_trait: true }),
     ]);
     const TEMPLATE: AttributeTemplate = template!(Word, NameValueStr: "reason");
 

compiler/rustc_passes/messages.ftl

@@ -427,7 +427,7 @@ passes_must_not_suspend =
     .label = is not a struct, enum, union, or trait
 
 passes_must_use_no_effect =
-    `#[must_use]` has no effect when applied to {$article} {$target}
+    this attribute is not allowed on this target when applied to {$article} {$target}
 
 passes_no_link =
     attribute should be applied to an `extern crate` item

tests/ui/attributes/positions/used.rs

@@ -4,20 +4,20 @@
 #[used]
 static FOO: u32 = 0; // OK
 
-#[used] //~ ERROR attribute must be applied to a `static` variable
+#[used] //~ ERROR this attribute is not allowed on this target
 fn foo() {}
 
-#[used] //~ ERROR attribute must be applied to a `static` variable
+#[used] //~ ERROR this attribute is not allowed on this target
 struct Foo {}
 
-#[used] //~ ERROR attribute must be applied to a `static` variable
+#[used] //~ ERROR this attribute is not allowed on this target
 trait Bar {}
 
-#[used] //~ ERROR attribute must be applied to a `static` variable
+#[used] //~ ERROR this attribute is not allowed on this target
 impl Bar for Foo {}
 
 // Regression test for <https://github.com/rust-lang/rust/issues/126789>.
 extern "C" {
-    #[used] //~ ERROR attribute must be applied to a `static` variable
+    #[used] //~ ERROR this attribute is not allowed on this target
     static BAR: i32;
 }

tests/ui/attributes/positions/used.stderr

@@ -1,42 +1,32 @@
-error: attribute must be applied to a `static` variable
-  --> $DIR/used.rs:7:1
+error: this attribute is not allowed on this target
+  --> $DIR/used.rs:7:3
    |
 LL | #[used]
-   | ^^^^^^^
-LL | fn foo() {}
-   | ----------- but this is a function
+   |   ^^^^
 
-error: attribute must be applied to a `static` variable
-  --> $DIR/used.rs:10:1
+error: this attribute is not allowed on this target
+  --> $DIR/used.rs:10:3
    |
 LL | #[used]
-   | ^^^^^^^
-LL | struct Foo {}
-   | ------------- but this is a struct
+   |   ^^^^
 
-error: attribute must be applied to a `static` variable
-  --> $DIR/used.rs:13:1
+error: this attribute is not allowed on this target
+  --> $DIR/used.rs:13:3
    |
 LL | #[used]
-   | ^^^^^^^
-LL | trait Bar {}
-   | ------------ but this is a trait
+   |   ^^^^
 
-error: attribute must be applied to a `static` variable
-  --> $DIR/used.rs:16:1
+error: this attribute is not allowed on this target
+  --> $DIR/used.rs:16:3
    |
 LL | #[used]
-   | ^^^^^^^
-LL | impl Bar for Foo {}
-   | ------------------- but this is a trait implementation block
+   |   ^^^^
 
-error: attribute must be applied to a `static` variable
-  --> $DIR/used.rs:21:5
+error: this attribute is not allowed on this target
+  --> $DIR/used.rs:21:7
    |
 LL |     #[used]
-   |     ^^^^^^^
-LL |     static BAR: i32;
-   |     ---------------- but this is a foreign static item
+   |       ^^^^
 
 error: aborting due to 5 previous errors
 

tests/ui/attributes/rustc_skip_during_method_dispatch.rs

@@ -32,7 +32,7 @@ trait String {}
 trait OK {}
 
 #[rustc_skip_during_method_dispatch(array)]
-//~^ ERROR: attribute should be applied to a trait
+//~^ ERROR: this attribute is not allowed on this target
 impl OK for () {}
 
 fn main() {}

tests/ui/attributes/rustc_skip_during_method_dispatch.stderr

@@ -61,14 +61,11 @@ LL | #[rustc_skip_during_method_dispatch("array")]
    | |                                   didn't expect a literal here
    | help: must be of the form: `#[rustc_skip_during_method_dispatch(array, boxed_slice)]`
 
-error: attribute should be applied to a trait
-  --> $DIR/rustc_skip_during_method_dispatch.rs:34:1
+error: this attribute is not allowed on this target
+  --> $DIR/rustc_skip_during_method_dispatch.rs:34:3
    |
 LL | #[rustc_skip_during_method_dispatch(array)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-LL |
-LL | impl OK for () {}
-   | ----------------- not a trait
+   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 8 previous errors
 

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.rs

@@ -70,7 +70,7 @@
 //~^ WARN attribute should be applied to a function or static
 //~^^ WARN this was previously accepted by the compiler
 #![must_use]
-//~^ WARN `#[must_use]` has no effect
+//~^ WARN this attribute is not allowed on this target
 // see issue-43106-gating-of-stable.rs
 // see issue-43106-gating-of-unstable.rs
 // see issue-43106-gating-of-deprecated.rs
@@ -598,17 +598,17 @@ mod deprecated {
     #[deprecated] impl super::StructForDeprecated { }
 }
 
-#[must_use] //~ WARN `#[must_use]` has no effect
+#[must_use] //~ WARN this attribute is not allowed on this target
 mod must_use {
-    mod inner { #![must_use] } //~ WARN `#[must_use]` has no effect
+    mod inner { #![must_use] } //~ WARN this attribute is not allowed on this target
 
     #[must_use] fn f() { }
 
     #[must_use] struct S;
 
-    #[must_use] type T = S; //~ WARN `#[must_use]` has no effect
+    #[must_use] type T = S; //~ WARN this attribute is not allowed on this target
 
-    #[must_use] impl S { } //~ WARN `#[must_use]` has no effect
+    #[must_use] impl S { } //~ WARN this attribute is not allowed on this target
 }
 
 #[windows_subsystem = "windows"]

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.stderr

@@ -307,7 +307,7 @@ LL | | }
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
-warning: `#[must_use]` has no effect when applied to a module
+warning: this attribute is not allowed on this target when applied to a module
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:601:1
    |
 LL | #[must_use]
@@ -391,7 +391,7 @@ LL | #![link_section = "1800"]
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
-warning: `#[must_use]` has no effect when applied to a module
+warning: this attribute is not allowed on this target when applied to a module
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:72:1
    |
 LL | #![must_use]
@@ -911,19 +911,19 @@ LL |     #[link()] extern "Rust" {}
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
-warning: `#[must_use]` has no effect when applied to a module
+warning: this attribute is not allowed on this target when applied to a module
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:603:17
    |
 LL |     mod inner { #![must_use] }
    |                 ^^^^^^^^^^^^
 
-warning: `#[must_use]` has no effect when applied to a type alias
+warning: this attribute is not allowed on this target when applied to a type alias
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:609:5
    |
 LL |     #[must_use] type T = S;
    |     ^^^^^^^^^^^
 
-warning: `#[must_use]` has no effect when applied to an inherent implementation block
+warning: this attribute is not allowed on this target when applied to an inherent implementation block
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:611:5
    |
 LL |     #[must_use] impl S { }

tests/ui/lint/unused/unused_attributes-must_use.rs

@@ -2,18 +2,18 @@
 #![deny(unused_attributes, unused_must_use)]
 #![feature(asm_experimental_arch, stmt_expr_attributes, trait_alias)]
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 extern crate std as std2;
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 mod test_mod {}
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 use std::arch::global_asm;
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 const CONST: usize = 4;
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 #[no_mangle]
 static STATIC: usize = 4;
 
@@ -30,7 +30,7 @@ union U {
     unit: (),
 }
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 impl U {
     #[must_use]
     fn method() -> i32 {
@@ -44,10 +44,10 @@ fn foo() -> i64 {
     4
 }
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 extern "Rust" {
     #[link_name = "STATIC"]
-    #[must_use] //~ ERROR `#[must_use]` has no effect
+    #[must_use] //~ ERROR this attribute is not allowed on this target
     static FOREIGN_STATIC: usize;
 
     #[link_name = "foo"]
@@ -58,16 +58,16 @@ extern "Rust" {
 #[must_use] //~ ERROR unused attribute
 global_asm!("");
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 type UseMe = ();
 
-fn qux<#[must_use] T>(_: T) {} //~ ERROR `#[must_use]` has no effect
+fn qux<#[must_use] T>(_: T) {} //~ ERROR this attribute is not allowed on this target
 
 #[must_use]
 trait Use {
-    #[must_use] //~ ERROR `#[must_use]` has no effect
+    #[must_use] //~ ERROR this attribute is not allowed on this target
     const ASSOC_CONST: usize = 4;
-    #[must_use] //~ ERROR `#[must_use]` has no effect
+    #[must_use] //~ ERROR this attribute is not allowed on this target
     type AssocTy;
 
     #[must_use]
@@ -76,32 +76,32 @@ trait Use {
     }
 }
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 impl Use for () {
     type AssocTy = ();
 
-    #[must_use] //~ ERROR `#[must_use]` has no effect
+    #[must_use] //~ ERROR this attribute is not allowed on this target
     fn get_four(&self) -> usize {
         4
     }
 }
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 trait Alias = Use;
 
-#[must_use] //~ ERROR `#[must_use]` has no effect
+#[must_use] //~ ERROR this attribute is not allowed on this target
 macro_rules! cool_macro {
     () => {
         4
     };
 }
 
 fn main() {
-    #[must_use] //~ ERROR `#[must_use]` has no effect
+    #[must_use] //~ ERROR this attribute is not allowed on this target
     let x = || {};
     x();
 
-    let x = #[must_use] //~ ERROR `#[must_use]` has no effect
+    let x = #[must_use] //~ ERROR this attribute is not allowed on this target
     || {};
     x();
 
@@ -123,14 +123,14 @@ fn main() {
     ().get_four(); //~ ERROR that must be used
 
     match Some(4) {
-        #[must_use] //~ ERROR `#[must_use]` has no effect
+        #[must_use] //~ ERROR this attribute is not allowed on this target
         Some(res) => res,
         None => 0,
     };
 
     struct PatternField {
         foo: i32,
     }
-    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 s = PatternField { #[must_use]  foo: 123 }; //~ ERROR this attribute is not allowed on this target
+    let PatternField { #[must_use] foo } = s; //~ ERROR this attribute is not allowed on this target
 }