Port reexport_test_harness_main to attr parser

compiler/rustc_attr_parsing/src/attributes/test_attrs.rs

@@ -113,3 +113,30 @@ impl<S: Stage> NoArgsAttributeParser<S> for RustcVarianceOfOpaquesParser {
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
     const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcVarianceOfOpaques;
 }
+
+pub(crate) struct ReexportTestHarnessMainParser;
+
+impl<S: Stage> SingleAttributeParser<S> for ReexportTestHarnessMainParser {
+    const PATH: &[Symbol] = &[sym::reexport_test_harness_main];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Crate)]);
+    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+        let Some(nv) = args.name_value() else {
+            cx.expected_name_value(
+                args.span().unwrap_or(cx.inner_span),
+                Some(sym::reexport_test_harness_main),
+            );
+            return None;
+        };
+
+        let Some(name) = nv.value_as_str() else {
+            cx.expected_string_literal(nv.value_span, Some(nv.value_as_lit()));
+            return None;
+        };
+
+        Some(AttributeKind::ReexportTestHarnessMain(name))
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -188,6 +188,7 @@ attribute_parsers!(
         Single<PatternComplexityLimitParser>,
         Single<ProcMacroDeriveParser>,
         Single<RecursionLimitParser>,
+        Single<ReexportTestHarnessMainParser>,
         Single<RustcAllocatorZeroedVariantParser>,
         Single<RustcBuiltinMacroParser>,
         Single<RustcForceInlineParser>,

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -990,6 +990,9 @@ pub enum AttributeKind {
     /// Represents [`#[recursion_limit]`](https://doc.rust-lang.org/reference/attributes/limits.html#the-recursion_limit-attribute)
     RecursionLimit { attr_span: Span, limit_span: Span, limit: Limit },
 
+    /// Represents `#[reexport_test_harness_main]`
+    ReexportTestHarnessMain(Symbol),
+
     /// Represents [`#[repr]`](https://doc.rust-lang.org/stable/reference/type-layout.html#representations).
     Repr { reprs: ThinVec<(ReprAttr, Span)>, first_span: Span },
 

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -87,6 +87,7 @@ impl AttributeKind {
             ProcMacroDerive { .. } => No,
             ProfilerRuntime => No,
             RecursionLimit { .. } => No,
+            ReexportTestHarnessMain(..) => No,
             Repr { .. } => No,
             RustcAllocator => No,
             RustcAllocatorZeroed => No,

compiler/rustc_passes/src/check_attr.rs

@@ -284,6 +284,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     | AttributeKind::Pointee(..)
                     | AttributeKind::ProfilerRuntime
                     | AttributeKind::RecursionLimit { .. }
+                    | AttributeKind::ReexportTestHarnessMain(..)
                     // handled below this loop and elsewhere
                     | AttributeKind::Repr { .. }
                     | AttributeKind::RustcAllocator
@@ -414,8 +415,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             | sym::feature
                             | sym::register_tool
                             | sym::rustc_no_implicit_bounds
-                            | sym::test_runner
-                            | sym::reexport_test_harness_main,
+                            | sym::test_runner,
                             ..
                         ] => {}
                         [name, rest@..] => {

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

@@ -467,26 +467,26 @@ mod no_implicit_prelude {
 
 #[reexport_test_harness_main = "2900"]
 //~^ WARN crate-level attribute should be
-//~| HELP add a `!`
 mod reexport_test_harness_main {
+//~^ NOTE this attribute does not have an `!`, which means it is applied to this module
     mod inner { #![reexport_test_harness_main="2900"] }
-    //~^ WARN crate-level attribute should be
+    //~^ WARN the `#![reexport_test_harness_main]` attribute can only be used at the crate root
 
     #[reexport_test_harness_main = "2900"] fn f() { }
     //~^ WARN crate-level attribute should be
-    //~| HELP add a `!`
+    //~| NOTE this attribute does not have an `!`, which means it is applied to this function
 
     #[reexport_test_harness_main = "2900"] struct S;
     //~^ WARN crate-level attribute should be
-    //~| HELP add a `!`
+    //~| NOTE this attribute does not have an `!`, which means it is applied to this struct
 
     #[reexport_test_harness_main = "2900"] type T = S;
     //~^ WARN crate-level attribute should be
-    //~| HELP add a `!`
+    //~| NOTE this attribute does not have an `!`, which means it is applied to this type alias
 
     #[reexport_test_harness_main = "2900"] impl S { }
     //~^ WARN crate-level attribute should be
-    //~| HELP add a `!`
+    //~| NOTE this attribute does not have an `!`, which means it is applied to this implementation block
 }
 
 // Cannot feed "2700" to `#[macro_escape]` without signaling an error.

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

@@ -186,22 +186,6 @@ warning: unknown lint: `x5100`
 LL |     #[deny(x5100)] impl S { }
    |            ^^^^^
 
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:468:1
-   |
-LL | #[reexport_test_harness_main = "2900"]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-note: the lint level is defined here
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:36:9
-   |
-LL | #![warn(unused_attributes, unknown_lints)]
-   |         ^^^^^^^^^^^^^^^^^
-help: add a `!`
-   |
-LL | #![reexport_test_harness_main = "2900"]
-   |  +
-
 warning: attribute should be applied to an `extern` block with non-Rust ABI
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:710:1
    |
@@ -217,6 +201,11 @@ LL | | }
    | |_- not an `extern` block
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+note: the lint level is defined here
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:36:9
+   |
+LL | #![warn(unused_attributes, unknown_lints)]
+   |         ^^^^^^^^^^^^^^^^^
 
 warning: crate-level attribute should be an inner attribute
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:860:1
@@ -245,56 +234,6 @@ LL | #![feature(rust1)]
    |
    = note: `#[warn(stable_features)]` on by default
 
-warning: crate-level attribute should be in the root module
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:472:17
-   |
-LL |     mod inner { #![reexport_test_harness_main="2900"] }
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:475:5
-   |
-LL |     #[reexport_test_harness_main = "2900"] fn f() { }
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL |     #![reexport_test_harness_main = "2900"] fn f() { }
-   |      +
-
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:479:5
-   |
-LL |     #[reexport_test_harness_main = "2900"] struct S;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL |     #![reexport_test_harness_main = "2900"] struct S;
-   |      +
-
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:483:5
-   |
-LL |     #[reexport_test_harness_main = "2900"] type T = S;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL |     #![reexport_test_harness_main = "2900"] type T = S;
-   |      +
-
-warning: crate-level attribute should be an inner attribute
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:487:5
-   |
-LL |     #[reexport_test_harness_main = "2900"] impl S { }
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: add a `!`
-   |
-LL |     #![reexport_test_harness_main = "2900"] impl S { }
-   |      +
-
 warning: attribute should be applied to an `extern` block with non-Rust ABI
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:716:17
    |
@@ -771,6 +710,76 @@ LL |     #[no_implicit_prelude] impl S { }
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[no_implicit_prelude]` can be applied to crates and modules
 
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![reexport_test_harness_main]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:468:1
+   |
+LL | #[reexport_test_harness_main = "2900"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this module
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:470:1
+   |
+LL | / mod reexport_test_harness_main {
+LL | |
+LL | |     mod inner { #![reexport_test_harness_main="2900"] }
+...  |
+LL | | }
+   | |_^
+
+warning: the `#![reexport_test_harness_main]` attribute can only be used at the crate root
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:472:17
+   |
+LL |     mod inner { #![reexport_test_harness_main="2900"] }
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![reexport_test_harness_main]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:475:5
+   |
+LL |     #[reexport_test_harness_main = "2900"] fn f() { }
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this function
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:475:44
+   |
+LL |     #[reexport_test_harness_main = "2900"] fn f() { }
+   |                                            ^^^^^^^^^^
+
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![reexport_test_harness_main]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:479:5
+   |
+LL |     #[reexport_test_harness_main = "2900"] struct S;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this struct
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:479:44
+   |
+LL |     #[reexport_test_harness_main = "2900"] struct S;
+   |                                            ^^^^^^^^^
+
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![reexport_test_harness_main]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:483:5
+   |
+LL |     #[reexport_test_harness_main = "2900"] type T = S;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this type alias
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:483:44
+   |
+LL |     #[reexport_test_harness_main = "2900"] type T = S;
+   |                                            ^^^^^^^^^^^
+
+warning: crate-level attribute should be an inner attribute: add an exclamation mark: `#![reexport_test_harness_main]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:487:5
+   |
+LL |     #[reexport_test_harness_main = "2900"] impl S { }
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: this attribute does not have an `!`, which means it is applied to this implementation block
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:487:44
+   |
+LL |     #[reexport_test_harness_main = "2900"] impl S { }
+   |                                            ^^^^^^^^^^
+
 warning: `#[macro_escape]` attribute cannot be used on functions
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:500:5
    |