From e4777322534026b246592d8b80d915085df07cf6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Le=C3=B3n=20Orell=20Valerian=20Liehr?= <me@fmease.dev>
Date: Tue, 9 Sep 2025 18:45:23 +0200
Subject: [PATCH] =?UTF-8?q?Don't=20strip=20shebang=20in=20expr-ctxt=20`inc?=
 =?UTF-8?q?lude!(=E2=80=A6)`?=
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---
 .../rustc_builtin_macros/src/source_util.rs   |  4 +--
 .../include-macros/auxiliary/shebang-expr.rs  |  3 ++
 .../include-macros/auxiliary/shebang-items.rs |  3 ++
 .../ui/include-macros/shebang-in-expr-ctxt.rs | 16 +++++++++
 .../shebang-in-expr-ctxt.stderr               | 33 +++++++++++++++++++
 .../ui/include-macros/shebang-in-item-ctxt.rs |  4 +++
 6 files changed, 60 insertions(+), 3 deletions(-)
 create mode 100644 tests/ui/include-macros/auxiliary/shebang-expr.rs
 create mode 100644 tests/ui/include-macros/auxiliary/shebang-items.rs
 create mode 100644 tests/ui/include-macros/shebang-in-expr-ctxt.rs
 create mode 100644 tests/ui/include-macros/shebang-in-expr-ctxt.stderr
 create mode 100644 tests/ui/include-macros/shebang-in-item-ctxt.rs

diff --git a/compiler/rustc_builtin_macros/src/source_util.rs b/compiler/rustc_builtin_macros/src/source_util.rs
index 16adaab15c525..b063413bce36f 100644
--- a/compiler/rustc_builtin_macros/src/source_util.rs
+++ b/compiler/rustc_builtin_macros/src/source_util.rs
@@ -147,9 +147,7 @@ pub(crate) fn expand_include<'cx>(
             let mut p = unwrap_or_emit_fatal(new_parser_from_file(
                 self.psess,
                 &self.path,
-                // Don't strip frontmatter for backward compatibility, `---` may be the start of a
-                // manifold negation. FIXME: Ideally, we wouldn't strip shebangs here either.
-                StripTokens::Shebang,
+                StripTokens::Nothing,
                 Some(self.span),
             ));
             let expr = parse_expr(&mut p).ok()?;
diff --git a/tests/ui/include-macros/auxiliary/shebang-expr.rs b/tests/ui/include-macros/auxiliary/shebang-expr.rs
new file mode 100644
index 0000000000000..73e92b5a889ee
--- /dev/null
+++ b/tests/ui/include-macros/auxiliary/shebang-expr.rs
@@ -0,0 +1,3 @@
+#!/usr/bin/env my-rust-expr-evaluator
+
+2 * (1 + 3)
diff --git a/tests/ui/include-macros/auxiliary/shebang-items.rs b/tests/ui/include-macros/auxiliary/shebang-items.rs
new file mode 100644
index 0000000000000..b9011b62cc911
--- /dev/null
+++ b/tests/ui/include-macros/auxiliary/shebang-items.rs
@@ -0,0 +1,3 @@
+#!/usr/bin/env my-rust-script-runner
+
+fn main() {}
diff --git a/tests/ui/include-macros/shebang-in-expr-ctxt.rs b/tests/ui/include-macros/shebang-in-expr-ctxt.rs
new file mode 100644
index 0000000000000..b6d3fa9e076fd
--- /dev/null
+++ b/tests/ui/include-macros/shebang-in-expr-ctxt.rs
@@ -0,0 +1,16 @@
+// Check that we *don't* strip shebang in files that were `include`d in an expression or
+// expression statement context.
+// We do that to be consistent with frontmatter (see test `frontmatter/include-in-expr-ctxt.rs`).
+// While there could be niche use cases for such shebang, it seems more confusing than beneficial.
+
+fn main() {
+    // expr ctxt
+    _ = include!("auxiliary/shebang-expr.rs");
+    //~^ ERROR non-expression macro in expression position
+    //~? ERROR expected `[`, found `/`
+
+    // stmt ctxt (reuses expr expander)
+    include!("auxiliary/shebang-expr.rs");
+    //~^ ERROR non-statement macro in statement position
+    //~? ERROR expected `[`, found `/`
+}
diff --git a/tests/ui/include-macros/shebang-in-expr-ctxt.stderr b/tests/ui/include-macros/shebang-in-expr-ctxt.stderr
new file mode 100644
index 0000000000000..9e95b02a78dcb
--- /dev/null
+++ b/tests/ui/include-macros/shebang-in-expr-ctxt.stderr
@@ -0,0 +1,33 @@
+error: expected `[`, found `/`
+  --> $DIR/auxiliary/shebang-expr.rs:1:3
+   |
+LL | #!/usr/bin/env my-rust-expr-evaluator
+   |   ^ expected `[`
+   |
+   = note: the token sequence `#!` here looks like the start of a shebang interpreter directive but it is not
+   = help: if you meant this to be a shebang interpreter directive, move it to the very start of the file
+
+error: non-expression macro in expression position: include
+  --> $DIR/shebang-in-expr-ctxt.rs:8:9
+   |
+LL |     _ = include!("auxiliary/shebang-expr.rs");
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected `[`, found `/`
+  --> $DIR/auxiliary/shebang-expr.rs:1:3
+   |
+LL | #!/usr/bin/env my-rust-expr-evaluator
+   |   ^ expected `[`
+   |
+   = note: the token sequence `#!` here looks like the start of a shebang interpreter directive but it is not
+   = help: if you meant this to be a shebang interpreter directive, move it to the very start of the file
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: non-statement macro in statement position: include
+  --> $DIR/shebang-in-expr-ctxt.rs:13:5
+   |
+LL |     include!("auxiliary/shebang-expr.rs");
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
+
diff --git a/tests/ui/include-macros/shebang-in-item-ctxt.rs b/tests/ui/include-macros/shebang-in-item-ctxt.rs
new file mode 100644
index 0000000000000..3e0718e287f07
--- /dev/null
+++ b/tests/ui/include-macros/shebang-in-item-ctxt.rs
@@ -0,0 +1,4 @@
+// Ensure that we strip shebang in files `include`d in item contexts.
+//@ check-pass
+
+include!("auxiliary/shebang-items.rs");