From 9e5c9c14c7fb3bc6032fff6e9031e641ed2a104a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=AE=B8=E6=9D=B0=E5=8F=8B=20Jieyou=20Xu=20=28Joe=29?=
 <jieyouxu@outlook.com>
Date: Sun, 4 Aug 2024 01:42:14 +0000
Subject: [PATCH] tests: add regression test for incorrect "builtin attribute
 is checked" assertion ICE

See <https://github.com/rust-lang/rust/issues/128622>.
---
 tests/ui/attributes/check-builtin-attr-ice.rs | 58 +++++++++++++++++++
 .../attributes/check-builtin-attr-ice.stderr  | 21 +++++++
 2 files changed, 79 insertions(+)
 create mode 100644 tests/ui/attributes/check-builtin-attr-ice.rs
 create mode 100644 tests/ui/attributes/check-builtin-attr-ice.stderr

diff --git a/tests/ui/attributes/check-builtin-attr-ice.rs b/tests/ui/attributes/check-builtin-attr-ice.rs
new file mode 100644
index 00000000000..9ef5890601f
--- /dev/null
+++ b/tests/ui/attributes/check-builtin-attr-ice.rs
@@ -0,0 +1,58 @@
+//! Regression test for #128622.
+//!
+//! PR #128581 introduced an assertion that all builtin attributes are actually checked via
+//! `CheckAttrVisitor` and aren't accidentally usable on completely unrelated HIR nodes.
+//! Unfortunately, the check had correctness problems.
+//!
+//! The match on attribute path segments looked like
+//!
+//! ```rs,ignore
+//! [sym::should_panic] => /* check is implemented */
+//! match BUILTIN_ATTRIBUTE_MAP.get(name) {
+//!     // checked below
+//!     Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) => {}
+//!     Some(_) => {
+//!         if !name.as_str().starts_with("rustc_") {
+//!             span_bug!(
+//!                 attr.span,
+//!                 "builtin attribute {name:?} not handled by `CheckAttrVisitor`"
+//!             )
+//!         }
+//!     }
+//!     None => (),
+//! }
+//! ```
+//!
+//! However, it failed to account for edge cases such as an attribute whose:
+//!
+//! 1. path segments *starts* with a builtin attribute such as `should_panic`
+//! 2. which does not start with `rustc_`, and
+//! 3. is also an `AttributeType::Normal` attribute upon registration with the builtin attribute map
+//!
+//! These conditions when all satisfied cause the span bug to be issued for e.g.
+//! `#[should_panic::skip]` because the `[sym::should_panic]` arm is not matched (since it's
+//! `[sym::should_panic, sym::skip]`).
+//!
+//! This test checks that the span bug is not fired for such cases.
+//!
+//! issue: rust-lang/rust#128622
+
+// Notably, `should_panic` is a `AttributeType::Normal` attribute that is checked separately.
+
+struct Foo {
+    #[should_panic::skip]
+    //~^ ERROR failed to resolve
+    pub field: u8,
+
+    #[should_panic::a::b::c]
+    //~^ ERROR failed to resolve
+    pub field2: u8,
+}
+
+fn foo() {}
+
+fn main() {
+    #[deny::skip]
+    //~^ ERROR failed to resolve
+    foo();
+}
diff --git a/tests/ui/attributes/check-builtin-attr-ice.stderr b/tests/ui/attributes/check-builtin-attr-ice.stderr
new file mode 100644
index 00000000000..5a27da565a8
--- /dev/null
+++ b/tests/ui/attributes/check-builtin-attr-ice.stderr
@@ -0,0 +1,21 @@
+error[E0433]: failed to resolve: use of undeclared crate or module `should_panic`
+  --> $DIR/check-builtin-attr-ice.rs:43:7
+   |
+LL |     #[should_panic::skip]
+   |       ^^^^^^^^^^^^ use of undeclared crate or module `should_panic`
+
+error[E0433]: failed to resolve: use of undeclared crate or module `should_panic`
+  --> $DIR/check-builtin-attr-ice.rs:47:7
+   |
+LL |     #[should_panic::a::b::c]
+   |       ^^^^^^^^^^^^ use of undeclared crate or module `should_panic`
+
+error[E0433]: failed to resolve: use of undeclared crate or module `deny`
+  --> $DIR/check-builtin-attr-ice.rs:55:7
+   |
+LL |     #[deny::skip]
+   |       ^^^^ use of undeclared crate or module `deny`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0433`.