Use "Innermost" & "Outermost" terminology for AttributeOrder

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -15,7 +15,7 @@ pub(crate) struct OptimizeParser;
 
 impl<S: Stage> SingleAttributeParser<S> for OptimizeParser {
     const PATH: &[Symbol] = &[sym::optimize];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(List: "size|speed|none");
 
@@ -56,7 +56,7 @@ pub(crate) struct ExportNameParser;
 
 impl<S: Stage> SingleAttributeParser<S> for ExportNameParser {
     const PATH: &[rustc_span::Symbol] = &[sym::export_name];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
 

compiler/rustc_attr_parsing/src/attributes/deprecation.rs

@@ -36,7 +36,7 @@ fn get<S: Stage>(
 
 impl<S: Stage> SingleAttributeParser<S> for DeprecationParser {
     const PATH: &[Symbol] = &[sym::deprecated];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const TEMPLATE: AttributeTemplate = template!(
         Word,

compiler/rustc_attr_parsing/src/attributes/dummy.rs

@@ -9,7 +9,7 @@ use crate::parser::ArgParser;
 pub(crate) struct DummyParser;
 impl<S: Stage> SingleAttributeParser<S> for DummyParser {
     const PATH: &[Symbol] = &[sym::rustc_dummy];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Ignore;
     const TEMPLATE: AttributeTemplate = template!(Word); // Anything, really
 

compiler/rustc_attr_parsing/src/attributes/inline.rs

@@ -16,7 +16,7 @@ pub(crate) struct InlineParser;
 
 impl<S: Stage> SingleAttributeParser<S> for InlineParser {
     const PATH: &'static [Symbol] = &[sym::inline];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(Word, List: "always|never");
 
@@ -57,7 +57,7 @@ pub(crate) struct RustcForceInlineParser;
 
 impl<S: Stage> SingleAttributeParser<S> for RustcForceInlineParser {
     const PATH: &'static [Symbol] = &[sym::rustc_force_inline];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(Word, List: "reason", NameValueStr: "reason");
 

compiler/rustc_attr_parsing/src/attributes/link_attrs.rs

@@ -14,7 +14,7 @@ pub(crate) struct LinkNameParser;
 
 impl<S: Stage> SingleAttributeParser<S> for LinkNameParser {
     const PATH: &[Symbol] = &[sym::link_name];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
 
@@ -36,7 +36,7 @@ pub(crate) struct LinkSectionParser;
 
 impl<S: Stage> SingleAttributeParser<S> for LinkSectionParser {
     const PATH: &[Symbol] = &[sym::link_section];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
 

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -140,15 +140,15 @@ impl<T: SingleAttributeParser<S>, S: Stage> AttributeParser<S> for Single<T, S>
             if let Some(pa) = T::convert(cx, args) {
                 match T::ATTRIBUTE_ORDER {
                     // keep the first and report immediately. ignore this attribute
-                    AttributeOrder::KeepFirst => {
+                    AttributeOrder::KeepInnermost => {
                         if let Some((_, unused)) = group.1 {
                             T::ON_DUPLICATE.exec::<T>(cx, cx.attr_span, unused);
                             return;
                         }
                     }
                     // keep the new one and warn about the previous,
                     // then replace
-                    AttributeOrder::KeepLast => {
+                    AttributeOrder::KeepOutermost => {
                         if let Some((_, used)) = group.1 {
                             T::ON_DUPLICATE.exec::<T>(cx, used, cx.attr_span);
                         }
@@ -165,9 +165,6 @@ impl<T: SingleAttributeParser<S>, S: Stage> AttributeParser<S> for Single<T, S>
     }
 }
 
-// FIXME(jdonszelmann): logic is implemented but the attribute parsers needing
-// them will be merged in another PR
-#[allow(unused)]
 pub(crate) enum OnDuplicate<S: Stage> {
     /// Give a default warning
     Warn,
@@ -213,39 +210,29 @@ impl<S: Stage> OnDuplicate<S> {
         }
     }
 }
-//
-// FIXME(jdonszelmann): logic is implemented but the attribute parsers needing
-// them will be merged in another PR
-#[allow(unused)]
+
 pub(crate) enum AttributeOrder {
-    /// Duplicates after the first attribute will be an error. I.e. only keep the lowest attribute.
+    /// Duplicates after the innermost instance of the attribute will be an error/warning.
+    /// Only keep the lowest attribute.
     ///
-    /// Attributes are processed from bottom to top, so this raises an error on all the attributes
+    /// Attributes are processed from bottom to top, so this raises a warning/error on all the attributes
     /// further above the lowest one:
     /// ```
     /// #[stable(since="1.0")] //~ WARNING duplicated attribute
     /// #[stable(since="2.0")]
     /// ```
-    ///
-    /// This should be used where duplicates would be ignored, but carry extra
-    /// meaning that could cause confusion. For example, `#[stable(since="1.0")]
-    /// #[stable(since="2.0")]`, which version should be used for `stable`?
-    KeepFirst,
+    KeepInnermost,
 
-    /// Duplicates preceding the last instance of the attribute will be a
-    /// warning, with a note that this will be an error in the future.
+    /// Duplicates before the outermost instance of the attribute will be an error/warning.
+    /// Only keep the highest attribute.
     ///
-    /// Attributes are processed from bottom to top, so this raises a warning on all the attributes
-    /// below the higher one:
+    /// Attributes are processed from bottom to top, so this raises a warning/error on all the attributes
+    /// below the highest one:
     /// ```
     /// #[path="foo.rs"]
     /// #[path="bar.rs"] //~ WARNING duplicated attribute
     /// ```
-    ///
-    /// This is the same as `FutureWarnFollowing`, except the last attribute is
-    /// the one that is "used". Ideally these can eventually migrate to
-    /// `ErrorPreceding`.
-    KeepLast,
+    KeepOutermost,
 }
 
 /// An even simpler version of [`SingleAttributeParser`]:
@@ -271,7 +258,7 @@ impl<T: NoArgsAttributeParser<S>, S: Stage> Default for WithoutArgs<T, S> {
 
 impl<T: NoArgsAttributeParser<S>, S: Stage> SingleAttributeParser<S> for WithoutArgs<T, S> {
     const PATH: &[Symbol] = T::PATH;
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = T::ON_DUPLICATE;
     const TEMPLATE: AttributeTemplate = template!(Word);
 

compiler/rustc_attr_parsing/src/attributes/must_use.rs

@@ -12,7 +12,7 @@ pub(crate) struct MustUseParser;
 
 impl<S: Stage> SingleAttributeParser<S> for MustUseParser {
     const PATH: &[Symbol] = &[sym::must_use];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(Word, NameValueStr: "reason");
 

compiler/rustc_attr_parsing/src/attributes/path.rs

@@ -10,7 +10,7 @@ pub(crate) struct PathParser;
 
 impl<S: Stage> SingleAttributeParser<S> for PathParser {
     const PATH: &[Symbol] = &[sym::path];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: "file");
 

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

@@ -11,7 +11,7 @@ pub(crate) struct RustcLayoutScalarValidRangeStart;
 
 impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeStart {
     const PATH: &'static [Symbol] = &[sym::rustc_layout_scalar_valid_range_start];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const TEMPLATE: AttributeTemplate = template!(List: "start");
 
@@ -25,7 +25,7 @@ pub(crate) struct RustcLayoutScalarValidRangeEnd;
 
 impl<S: Stage> SingleAttributeParser<S> for RustcLayoutScalarValidRangeEnd {
     const PATH: &'static [Symbol] = &[sym::rustc_layout_scalar_valid_range_end];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const TEMPLATE: AttributeTemplate = template!(List: "end");
 
@@ -62,7 +62,7 @@ pub(crate) struct RustcObjectLifetimeDefaultParser;
 
 impl<S: Stage> SingleAttributeParser<S> for RustcObjectLifetimeDefaultParser {
     const PATH: &[rustc_span::Symbol] = &[sym::rustc_object_lifetime_default];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
     const TEMPLATE: AttributeTemplate = template!(Word);
 

compiler/rustc_attr_parsing/src/attributes/test_attrs.rs

@@ -11,7 +11,7 @@ pub(crate) struct IgnoreParser;
 
 impl<S: Stage> SingleAttributeParser<S> for IgnoreParser {
     const PATH: &[Symbol] = &[sym::ignore];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
     const TEMPLATE: AttributeTemplate = template!(Word, NameValueStr: "reason");
 

compiler/rustc_attr_parsing/src/attributes/traits.rs

@@ -12,7 +12,7 @@ pub(crate) struct SkipDuringMethodDispatchParser;
 
 impl<S: Stage> SingleAttributeParser<S> for SkipDuringMethodDispatchParser {
     const PATH: &[Symbol] = &[sym::rustc_skip_during_method_dispatch];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
 
     const TEMPLATE: AttributeTemplate = template!(List: "array, boxed_slice");

compiler/rustc_attr_parsing/src/attributes/transparency.rs

@@ -14,7 +14,7 @@ pub(crate) struct TransparencyParser;
 #[allow(rustc::diagnostic_outside_of_impl)]
 impl<S: Stage> SingleAttributeParser<S> for TransparencyParser {
     const PATH: &[Symbol] = &[sym::rustc_macro_transparency];
-    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepFirst;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Custom(|cx, used, unused| {
         cx.dcx().span_err(vec![used, unused], "multiple macro transparency attributes");
     });