3 files changed, 163 insertions, 0 deletions

diff --git a/crates/ide/src/diagnostics/unresolved_import.rs b/crates/ide/src/diagnostics/unresolved_import.rs
new file mode 100644
index 000000000..1cbf96ba1
--- /dev/null
+++ b/crates/ide/src/diagnostics/unresolved_import.rs
@@ -0,0 +1,90 @@
+use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: unresolved-import
+//
+// This diagnostic is triggered if rust-analyzer is unable to resolve a path in
+// a `use` declaration.
+pub(super) fn unresolved_import(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnresolvedImport,
+) -> Diagnostic {
+    Diagnostic::new(
+        "unresolved-import",
+        "unresolved import",
+        ctx.sema.diagnostics_display_range(d.decl.clone().map(|it| it.into())).range,
+    )
+    // This currently results in false positives in the following cases:
+    // - `cfg_if!`-generated code in libstd (we don't load the sysroot correctly)
+    // - `core::arch` (we don't handle `#[path = "../<path>"]` correctly)
+    // - proc macros and/or proc macro generated code
+    .experimental()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostics::tests::check_diagnostics;
+
+    #[test]
+    fn unresolved_import() {
+        check_diagnostics(
+            r#"
+use does_exist;
+use does_not_exist;
+  //^^^^^^^^^^^^^^ unresolved import
+
+mod does_exist {}
+"#,
+        );
+    }
+
+    #[test]
+    fn unresolved_import_in_use_tree() {
+        // Only the relevant part of a nested `use` item should be highlighted.
+        check_diagnostics(
+            r#"
+use does_exist::{Exists, DoesntExist};
+                       //^^^^^^^^^^^ unresolved import
+
+use {does_not_exist::*, does_exist};
+   //^^^^^^^^^^^^^^^^^ unresolved import
+
+use does_not_exist::{
+    a,
+  //^ unresolved import
+    b,
+  //^ unresolved import
+    c,
+  //^ unresolved import
+};
+
+mod does_exist {
+    pub struct Exists;
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn dedup_unresolved_import_from_unresolved_crate() {
+        check_diagnostics(
+            r#"
+//- /main.rs crate:main
+mod a {
+    extern crate doesnotexist;
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^ unresolved extern crate
+
+    // Should not error, since we already errored for the missing crate.
+    use doesnotexist::{self, bla, *};
+
+    use crate::doesnotexist;
+      //^^^^^^^^^^^^^^^^^^^ unresolved import
+}
+
+mod m {
+    use super::doesnotexist;
+      //^^^^^^^^^^^^^^^^^^^ unresolved import
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ide/src/diagnostics/unresolved_macro_call.rs b/crates/ide/src/diagnostics/unresolved_macro_call.rs
new file mode 100644
index 000000000..a3af332a4
--- /dev/null
+++ b/crates/ide/src/diagnostics/unresolved_macro_call.rs
@@ -0,0 +1,72 @@
+use hir::{db::AstDatabase, InFile};
+use syntax::{AstNode, SyntaxNodePtr};
+
+use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: unresolved-macro-call
+//
+// This diagnostic is triggered if rust-analyzer is unable to resolve the path
+// to a macro in a macro invocation.
+pub(super) fn unresolved_macro_call(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnresolvedMacroCall,
+) -> Diagnostic {
+    let last_path_segment = ctx.sema.db.parse_or_expand(d.macro_call.file_id).and_then(|root| {
+        d.macro_call
+            .value
+            .to_node(&root)
+            .path()
+            .and_then(|it| it.segment())
+            .and_then(|it| it.name_ref())
+            .map(|it| InFile::new(d.macro_call.file_id, SyntaxNodePtr::new(it.syntax())))
+    });
+    let diagnostics = last_path_segment.unwrap_or_else(|| d.macro_call.clone().map(|it| it.into()));
+
+    Diagnostic::new(
+        "unresolved-macro-call",
+        format!("unresolved macro `{}!`", d.path),
+        ctx.sema.diagnostics_display_range(diagnostics).range,
+    )
+    .experimental()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostics::tests::check_diagnostics;
+
+    #[test]
+    fn test_unresolved_macro_range() {
+        check_diagnostics(
+            r#"
+foo::bar!(92);
+   //^^^ unresolved macro `foo::bar!`
+"#,
+        );
+    }
+
+    #[test]
+    fn unresolved_legacy_scope_macro() {
+        check_diagnostics(
+            r#"
+macro_rules! m { () => {} }
+
+m!(); m2!();
+    //^^ unresolved macro `self::m2!`
+"#,
+        );
+    }
+
+    #[test]
+    fn unresolved_module_scope_macro() {
+        check_diagnostics(
+            r#"
+mod mac {
+#[macro_export]
+macro_rules! m { () => {} } }
+
+self::m!(); self::m2!();
+                //^^ unresolved macro `self::m2!`
+"#,
+        );
+    }
+}
diff --git a/crates/ide/src/diagnostics/unresolved_module.rs b/crates/ide/src/diagnostics/unresolved_module.rs
index 4c8c74ff7..b1da8f0e1 100644
--- a/crates/ide/src/diagnostics/unresolved_module.rs
+++ b/crates/ide/src/diagnostics/unresolved_module.rs
@@ -104,6 +104,7 @@ mod baz {}
                                 "unresolved-module",
                             ),
                         ),
+                        experimental: false,
                     },
                 ]
             "#]],