Add more docs to templates for attrs with incorrect arguments

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -16,7 +16,10 @@ use crate::{
     CfgMatchesLintEmitter, fluent_generated, parse_version, session_diagnostics, try_gate_cfg,
 };
 
-pub const CFG_TEMPLATE: AttributeTemplate = template!(List: &["predicate"]);
+pub const CFG_TEMPLATE: AttributeTemplate = template!(
+    List: &["predicate"],
+    "https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute"
+);
 
 pub fn parse_cfg_attr<'c, S: Stage>(
     cx: &'c mut AcceptContext<'_, '_, S>,

compiler/rustc_attr_parsing/src/attributes/inline.rs

@@ -18,7 +18,11 @@ impl<S: Stage> SingleAttributeParser<S> for InlineParser {
     const PATH: &'static [Symbol] = &[sym::inline];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
-    const TEMPLATE: AttributeTemplate = template!(Word, List: &["always", "never"]);
+    const TEMPLATE: AttributeTemplate = template!(
+        Word,
+        List: &["always", "never"],
+        "https://doc.rust-lang.org/reference/attributes/codegen.html#the-inline-attribute"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         match args {

compiler/rustc_attr_parsing/src/attributes/link_attrs.rs

@@ -16,7 +16,10 @@ impl<S: Stage> SingleAttributeParser<S> for LinkNameParser {
     const PATH: &[Symbol] = &[sym::link_name];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
-    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
+    const TEMPLATE: AttributeTemplate = template!(
+        NameValueStr: "name",
+        "https://doc.rust-lang.org/reference/items/external-blocks.html#the-link_name-attribute"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
@@ -38,7 +41,10 @@ impl<S: Stage> SingleAttributeParser<S> for LinkSectionParser {
     const PATH: &[Symbol] = &[sym::link_section];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
-    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
+    const TEMPLATE: AttributeTemplate = template!(
+        NameValueStr: "name",
+        "https://doc.rust-lang.org/reference/abi.html#the-link_section-attribute"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {
@@ -94,7 +100,10 @@ impl<S: Stage> SingleAttributeParser<S> for LinkOrdinalParser {
     const PATH: &[Symbol] = &[sym::link_ordinal];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const TEMPLATE: AttributeTemplate = template!(List: &["ordinal"]);
+    const TEMPLATE: AttributeTemplate = template!(
+        List: &["ordinal"],
+        "https://doc.rust-lang.org/reference/items/external-blocks.html#the-link_ordinal-attribute"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let ordinal = parse_single_integer(cx, args)?;

compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs

@@ -31,7 +31,10 @@ pub(crate) struct MacroUseParser {
     first_span: Option<Span>,
 }
 
-const MACRO_USE_TEMPLATE: AttributeTemplate = template!(Word, List: &["name1, name2, ..."]);
+const MACRO_USE_TEMPLATE: AttributeTemplate = template!(
+    Word, List: &["name1, name2, ..."],
+    "https://doc.rust-lang.org/reference/macros-by-example.html#the-macro_use-attribute"
+);
 
 impl<S: Stage> AttributeParser<S> for MacroUseParser {
     const ATTRIBUTES: AcceptMapping<Self, S> = &[(

compiler/rustc_attr_parsing/src/attributes/must_use.rs

@@ -14,7 +14,10 @@ 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 TEMPLATE: AttributeTemplate = template!(Word, NameValueStr: "reason");
+    const TEMPLATE: AttributeTemplate = template!(
+        Word, NameValueStr: "reason",
+        "https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-must_use-attribute"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         Some(AttributeKind::MustUse {

compiler/rustc_attr_parsing/src/attributes/path.rs

@@ -12,7 +12,10 @@ impl<S: Stage> SingleAttributeParser<S> for PathParser {
     const PATH: &[Symbol] = &[sym::path];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
-    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "file");
+    const TEMPLATE: AttributeTemplate = template!(
+        NameValueStr: "file",
+        "https://doc.rust-lang.org/reference/items/modules.html#the-path-attribute"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let Some(nv) = args.name_value() else {

compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs

@@ -28,8 +28,10 @@ impl<S: Stage> SingleAttributeParser<S> for ProcMacroDeriveParser {
     const PATH: &[Symbol] = &[sym::proc_macro_derive];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
-    const TEMPLATE: AttributeTemplate =
-        template!(List: &["TraitName", "TraitName, attributes(name1, name2, ...)"]);
+    const TEMPLATE: AttributeTemplate = template!(
+        List: &["TraitName", "TraitName, attributes(name1, name2, ...)"],
+        "https://doc.rust-lang.org/reference/procedural-macros.html#derive-macros"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         let (trait_name, helper_attrs) = parse_derive_like(cx, args, true)?;

compiler/rustc_attr_parsing/src/attributes/repr.rs

@@ -26,7 +26,10 @@ impl<S: Stage> CombineAttributeParser<S> for ReprParser {
     const CONVERT: ConvertFn<Self::Item> =
         |items, first_span| AttributeKind::Repr { reprs: items, first_span };
     // FIXME(jdonszelmann): never used
-    const TEMPLATE: AttributeTemplate = template!(List: &["C", "Rust", "transparent", "align(...)", "packed(...)", "<integer type>"]);
+    const TEMPLATE: AttributeTemplate = template!(
+        List: &["C", "Rust", "transparent", "align(...)", "packed(...)", "<integer type>"],
+        "https://doc.rust-lang.org/reference/type-layout.html#representations"
+    );
 
     fn extend<'c>(
         cx: &'c mut AcceptContext<'_, '_, S>,

compiler/rustc_attr_parsing/src/attributes/test_attrs.rs

@@ -13,7 +13,10 @@ impl<S: Stage> SingleAttributeParser<S> for IgnoreParser {
     const PATH: &[Symbol] = &[sym::ignore];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
-    const TEMPLATE: AttributeTemplate = template!(Word, NameValueStr: "reason");
+    const TEMPLATE: AttributeTemplate = template!(
+        Word, NameValueStr: "reason",
+        "https://doc.rust-lang.org/reference/attributes/testing.html#the-ignore-attribute"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         Some(AttributeKind::Ignore {
@@ -51,8 +54,10 @@ impl<S: Stage> SingleAttributeParser<S> for ShouldPanicParser {
     const PATH: &[Symbol] = &[sym::should_panic];
     const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
-    const TEMPLATE: AttributeTemplate =
-        template!(Word, List: &[r#"expected = "reason""#], NameValueStr: "reason");
+    const TEMPLATE: AttributeTemplate = template!(
+        Word, List: &[r#"expected = "reason""#], NameValueStr: "reason",
+        "https://doc.rust-lang.org/reference/attributes/testing.html#the-should_panic-attribute"
+    );
 
     fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
         Some(AttributeKind::ShouldPanic {

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -691,6 +691,9 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
             }
         }
 
+        if let Some(link) = self.template.docs {
+            diag.note(format!("for more information, visit <{link}>"));
+        }
         let suggestions = self.template.suggestions(false, &name);
         diag.span_suggestions(
             self.attr_span,

compiler/rustc_feature/src/builtin_attrs.rs

@@ -609,7 +609,10 @@ pub static BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
     ungated!(
         repr, Normal,
-        template!(List: &["C"], "https://doc.rust-lang.org/reference/type-layout.html#representations"),
+        template!(
+            List: &["C", "Rust", "transparent", "align(...)", "packed(...)", "<integer type>"],
+            "https://doc.rust-lang.org/reference/type-layout.html#representations"
+        ),
         DuplicatesOk, EncodeCrossCrate::No
     ),
     // FIXME(#82232, #143834): temporarily renamed to mitigate `#[align]` nameres ambiguity

tests/ui/attributes/invalid-macro-use.rs

@@ -8,21 +8,25 @@ extern crate std as s1;
 #[macro_use(5)]
 //~^ ERROR malformed `macro_use` attribute input
 //~| NOTE expected a valid identifier here
+//~| NOTE for more information, visit
 extern crate std as s2;
 
 #[macro_use(a = "b")]
 //~^ ERROR malformed `macro_use` attribute input
 //~| NOTE didn't expect any arguments here
+//~| NOTE for more information, visit
 extern crate std as s3;
 
 #[macro_use(a(b))]
 //~^ ERROR malformed `macro_use` attribute input
 //~| NOTE didn't expect any arguments here
+//~| NOTE for more information, visit
 extern crate std as s4;
 
 #[macro_use(a::b)]
 //~^ ERROR malformed `macro_use` attribute input
 //~| NOTE expected a valid identifier here
+//~| NOTE for more information, visit
 extern crate std as s5;
 
 #[macro_use(a)]

tests/ui/attributes/invalid-macro-use.stderr

@@ -1,11 +1,11 @@
 error[E0469]: imported macro not found
-  --> $DIR/invalid-macro-use.rs:47:13
+  --> $DIR/invalid-macro-use.rs:51:13
    |
 LL | #[macro_use(a)]
    |             ^
 
 error[E0469]: imported macro not found
-  --> $DIR/invalid-macro-use.rs:49:13
+  --> $DIR/invalid-macro-use.rs:53:13
    |
 LL | #[macro_use(b)]
    |             ^
@@ -24,6 +24,7 @@ LL | #[macro_use(5)]
    |             |
    |             expected a valid identifier here
    |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/macros-by-example.html#the-macro_use-attribute>
 help: try changing it to one of the following valid forms of the attribute
    |
 LL - #[macro_use(5)]
@@ -34,13 +35,14 @@ LL + #[macro_use]
    |
 
 error[E0565]: malformed `macro_use` attribute input
-  --> $DIR/invalid-macro-use.rs:13:1
+  --> $DIR/invalid-macro-use.rs:14:1
    |
 LL | #[macro_use(a = "b")]
    | ^^^^^^^^^^^^^^-----^^
    |               |
    |               didn't expect any arguments here
    |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/macros-by-example.html#the-macro_use-attribute>
 help: try changing it to one of the following valid forms of the attribute
    |
 LL - #[macro_use(a = "b")]
@@ -51,13 +53,14 @@ LL + #[macro_use]
    |
 
 error[E0565]: malformed `macro_use` attribute input
-  --> $DIR/invalid-macro-use.rs:18:1
+  --> $DIR/invalid-macro-use.rs:20:1
    |
 LL | #[macro_use(a(b))]
    | ^^^^^^^^^^^^^---^^
    |              |
    |              didn't expect any arguments here
    |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/macros-by-example.html#the-macro_use-attribute>
 help: try changing it to one of the following valid forms of the attribute
    |
 LL - #[macro_use(a(b))]
@@ -68,13 +71,14 @@ LL + #[macro_use]
    |
 
 error[E0539]: malformed `macro_use` attribute input
-  --> $DIR/invalid-macro-use.rs:23:1
+  --> $DIR/invalid-macro-use.rs:26:1
    |
 LL | #[macro_use(a::b)]
    | ^^^^^^^^^^^^----^^
    |             |
    |             expected a valid identifier here
    |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/macros-by-example.html#the-macro_use-attribute>
 help: try changing it to one of the following valid forms of the attribute
    |
 LL - #[macro_use(a::b)]
@@ -85,13 +89,13 @@ LL + #[macro_use]
    |
 
 error: unused attribute
-  --> $DIR/invalid-macro-use.rs:28:1
+  --> $DIR/invalid-macro-use.rs:32:1
    |
 LL | #[macro_use(a)]
    | ^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/invalid-macro-use.rs:30:1
+  --> $DIR/invalid-macro-use.rs:34:1
    |
 LL | #[macro_use]
    | ^^^^^^^^^^^^
@@ -102,25 +106,25 @@ LL | #![deny(unused_attributes)]
    |         ^^^^^^^^^^^^^^^^^
 
 error: unused attribute
-  --> $DIR/invalid-macro-use.rs:36:1
+  --> $DIR/invalid-macro-use.rs:40:1
    |
 LL | #[macro_use(a)]
    | ^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/invalid-macro-use.rs:34:1
+  --> $DIR/invalid-macro-use.rs:38:1
    |
 LL | #[macro_use]
    | ^^^^^^^^^^^^
 
 error: unused attribute
-  --> $DIR/invalid-macro-use.rs:42:1
+  --> $DIR/invalid-macro-use.rs:46:1
    |
 LL | #[macro_use]
    | ^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/invalid-macro-use.rs:40:1
+  --> $DIR/invalid-macro-use.rs:44:1
    |
 LL | #[macro_use]
    | ^^^^^^^^^^^^

tests/ui/attributes/malformed-attrs.stderr

@@ -6,6 +6,8 @@ LL | #[cfg]
    | |
    | expected this to be a list
    | help: must be of the form: `#[cfg(predicate)]`
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
 
 error: malformed `cfg_attr` attribute input
   --> $DIR/malformed-attrs.rs:101:1
@@ -354,14 +356,24 @@ error[E0539]: malformed `rustc_macro_transparency` attribute input
   --> $DIR/malformed-attrs.rs:43:1
    |
 LL | #[rustc_macro_transparency]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[rustc_macro_transparency = "transparent|semitransparent|opaque"]`
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: try changing it to one of the following valid forms of the attribute
+   |
+LL | #[rustc_macro_transparency = "opaque"]
+   |                            ++++++++++
+LL | #[rustc_macro_transparency = "semitransparent"]
+   |                            +++++++++++++++++++
+LL | #[rustc_macro_transparency = "transparent"]
+   |                            +++++++++++++++
 
 error[E0539]: malformed `repr` attribute input
   --> $DIR/malformed-attrs.rs:45:1
    |
 LL | #[repr]
    | ^^^^^^^ expected this to be a list
    |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/type-layout.html#representations>
 help: try changing it to one of the following valid forms of the attribute
    |
 LL | #[repr(<integer type>)]
@@ -496,12 +508,16 @@ error[E0539]: malformed `link_name` attribute input
    |
 LL | #[link_name]
    | ^^^^^^^^^^^^ help: must be of the form: `#[link_name = "name"]`
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/items/external-blocks.html#the-link_name-attribute>
 
 error[E0539]: malformed `link_section` attribute input
   --> $DIR/malformed-attrs.rs:85:1
    |
 LL | #[link_section]
    | ^^^^^^^^^^^^^^^ help: must be of the form: `#[link_section = "name"]`
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/abi.html#the-link_section-attribute>
 
 error[E0539]: malformed `coverage` attribute input
   --> $DIR/malformed-attrs.rs:87:1
@@ -560,6 +576,7 @@ LL | #[must_use = 1]
    |              |
    |              expected a string literal here
    |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-must_use-attribute>
 help: try changing it to one of the following valid forms of the attribute
    |
 LL - #[must_use = 1]
@@ -575,6 +592,7 @@ error[E0539]: malformed `proc_macro_derive` attribute input
 LL | #[proc_macro_derive]
    | ^^^^^^^^^^^^^^^^^^^^ expected this to be a list
    |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/procedural-macros.html#derive-macros>
 help: try changing it to one of the following valid forms of the attribute
    |
 LL | #[proc_macro_derive(TraitName)]
@@ -635,6 +653,8 @@ LL |     #[link_ordinal]
    |     |
    |     expected this to be a list
    |     help: must be of the form: `#[link_ordinal(ordinal)]`
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/items/external-blocks.html#the-link_ordinal-attribute>
 
 error[E0565]: malformed `ffi_const` attribute input
   --> $DIR/malformed-attrs.rs:168:5

tests/ui/attributes/malformed-reprs.stderr

@@ -4,6 +4,7 @@ error[E0539]: malformed `repr` attribute input
 LL | #![repr]
    | ^^^^^^^^ expected this to be a list
    |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/type-layout.html#representations>
 help: try changing it to one of the following valid forms of the attribute
    |
 LL - #![repr]