1 files changed, 218 insertions, 0 deletions
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/macro_error.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/macro_error.rs
new file mode 100644
index 000000000..d6a66dc15
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/handlers/macro_error.rs
@@ -0,0 +1,218 @@
+use crate::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: macro-error
+//
+// This diagnostic is shown for macro expansion errors.
+pub(crate) fn macro_error(ctx: &DiagnosticsContext<'_>, d: &hir::MacroError) -> Diagnostic {
+    // Use more accurate position if available.
+    let display_range = d
+        .precise_location
+        .unwrap_or_else(|| ctx.sema.diagnostics_display_range(d.node.clone()).range);
+
+    Diagnostic::new("macro-error", d.message.clone(), display_range).experimental()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        tests::{check_diagnostics, check_diagnostics_with_config},
+        DiagnosticsConfig,
+    };
+
+    #[test]
+    fn builtin_macro_fails_expansion() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+
+#[rustc_builtin_macro]
+macro_rules! compile_error { () => {} }
+
+  include!("doesntexist");
+//^^^^^^^ error: failed to load file `doesntexist`
+
+  compile_error!("compile_error macro works");
+//^^^^^^^^^^^^^ error: compile_error macro works
+            "#,
+        );
+    }
+
+    #[test]
+    fn eager_macro_concat() {
+        // FIXME: this is incorrectly handling `$crate`, resulting in a wrong diagnostic.
+        // See: https://github.com/rust-lang/rust-analyzer/issues/10300
+
+        check_diagnostics(
+            r#"
+//- /lib.rs crate:lib deps:core
+use core::{panic, concat};
+
+mod private {
+    pub use core::concat;
+}
+
+macro_rules! m {
+    () => {
+        panic!(concat!($crate::private::concat!("")));
+    };
+}
+
+fn f() {
+    m!();
+  //^^^^ error: unresolved macro `$crate::private::concat!`
+}
+
+//- /core.rs crate:core
+#[macro_export]
+#[rustc_builtin_macro]
+macro_rules! concat { () => {} }
+
+pub macro panic {
+    ($msg:expr) => (
+        $crate::panicking::panic_str($msg)
+    ),
+}
+            "#,
+        );
+    }
+
+    #[test]
+    fn include_macro_should_allow_empty_content() {
+        let mut config = DiagnosticsConfig::default();
+
+        // FIXME: This is a false-positive, the file is actually linked in via
+        // `include!` macro
+        config.disabled.insert("unlinked-file".to_string());
+
+        check_diagnostics_with_config(
+            config,
+            r#"
+//- /lib.rs
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+
+include!("foo/bar.rs");
+//- /foo/bar.rs
+// empty
+"#,
+        );
+    }
+
+    #[test]
+    fn good_out_dir_diagnostic() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+#[rustc_builtin_macro]
+macro_rules! env { () => {} }
+#[rustc_builtin_macro]
+macro_rules! concat { () => {} }
+
+  include!(concat!(env!("OUT_DIR"), "/out.rs"));
+//^^^^^^^ error: `OUT_DIR` not set, enable "build scripts" to fix
+"#,
+        );
+    }
+
+    #[test]
+    fn register_attr_and_tool() {
+        cov_mark::check!(register_attr);
+        cov_mark::check!(register_tool);
+        check_diagnostics(
+            r#"
+#![register_tool(tool)]
+#![register_attr(attr)]
+
+#[tool::path]
+#[attr]
+struct S;
+"#,
+        );
+        // NB: we don't currently emit diagnostics here
+    }
+
+    #[test]
+    fn macro_diag_builtin() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! env {}
+
+#[rustc_builtin_macro]
+macro_rules! include {}
+
+#[rustc_builtin_macro]
+macro_rules! compile_error {}
+
+#[rustc_builtin_macro]
+macro_rules! format_args { () => {} }
+
+fn main() {
+    // Test a handful of built-in (eager) macros:
+
+    include!(invalid);
+  //^^^^^^^ error: could not convert tokens
+    include!("does not exist");
+  //^^^^^^^ error: failed to load file `does not exist`
+
+    env!(invalid);
+  //^^^ error: could not convert tokens
+
+    env!("OUT_DIR");
+  //^^^ error: `OUT_DIR` not set, enable "build scripts" to fix
+
+    compile_error!("compile_error works");
+  //^^^^^^^^^^^^^ error: compile_error works
+
+    // Lazy:
+
+    format_args!();
+  //^^^^^^^^^^^ error: no rule matches input tokens
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn macro_rules_diag() {
+        check_diagnostics(
+            r#"
+macro_rules! m {
+    () => {};
+}
+fn f() {
+    m!();
+
+    m!(hi);
+  //^ error: leftover tokens
+}
+      "#,
+        );
+    }
+    #[test]
+    fn dollar_crate_in_builtin_macro() {
+        check_diagnostics(
+            r#"
+#[macro_export]
+#[rustc_builtin_macro]
+macro_rules! format_args {}
+
+#[macro_export]
+macro_rules! arg { () => {} }
+
+#[macro_export]
+macro_rules! outer {
+    () => {
+        $crate::format_args!( "", $crate::arg!(1) )
+    };
+}
+
+fn f() {
+    outer!();
+} //^^^^^^^^ error: leftover tokens
+"#,
+        )
+    }
+}