From 49c425dfcfdd7e4ef238ed38620880075dde1929 Mon Sep 17 00:00:00 2001
From: mu001999 <mu001999@outlook.com>
Date: Thu, 25 Sep 2025 09:53:57 +0800
Subject: [PATCH] Disable use $crate::{self}

---
 compiler/rustc_resolve/src/build_reduced_graph.rs  |  6 ++++++
 tests/ui/dollar-crate/use-dollar-crate-self.rs     |  9 +++++++++
 tests/ui/dollar-crate/use-dollar-crate-self.stderr | 13 +++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 tests/ui/dollar-crate/use-dollar-crate-self.rs
 create mode 100644 tests/ui/dollar-crate/use-dollar-crate-self.stderr

diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
index fa3c06059b3da..d6289493428ea 100644
--- a/compiler/rustc_resolve/src/build_reduced_graph.rs
+++ b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -706,6 +706,12 @@ impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
                     }
 
                     e.emit();
+                } else if let &[self_span] = &self_spans[..]
+                    && prefix.len() == 1
+                    && prefix[0].ident.name == kw::DollarCrate
+                {
+                    // Disallow `use $crate::{self};`
+                    self.r.dcx().emit_err(errors::CrateImported { span: self_span });
                 }
 
                 for &(ref tree, id) in items {
diff --git a/tests/ui/dollar-crate/use-dollar-crate-self.rs b/tests/ui/dollar-crate/use-dollar-crate-self.rs
new file mode 100644
index 0000000000000..fc9898ef151ac
--- /dev/null
+++ b/tests/ui/dollar-crate/use-dollar-crate-self.rs
@@ -0,0 +1,9 @@
+macro_rules! foo {
+    () => {
+        use $crate::{self}; //~ ERROR `$crate` may not be imported
+    };
+}
+
+foo!();
+
+fn main() {}
diff --git a/tests/ui/dollar-crate/use-dollar-crate-self.stderr b/tests/ui/dollar-crate/use-dollar-crate-self.stderr
new file mode 100644
index 0000000000000..262bb56dc50b7
--- /dev/null
+++ b/tests/ui/dollar-crate/use-dollar-crate-self.stderr
@@ -0,0 +1,13 @@
+error: `$crate` may not be imported
+  --> $DIR/use-dollar-crate-self.rs:3:22
+   |
+LL |         use $crate::{self};
+   |                      ^^^^
+...
+LL | foo!();
+   | ------ in this macro invocation
+   |
+   = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 1 previous error
+