3 files changed, 82 insertions, 34 deletions

diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
index 337a904b6..075aae8d5 100644
--- a/crates/ide/src/diagnostics.rs
+++ b/crates/ide/src/diagnostics.rs
@@ -4,6 +4,8 @@
 //! macro-expanded files, but we need to present them to the users in terms of
 //! original files. So we need to map the ranges.
 
+mod unresolved_module;
+
 mod fixes;
 mod field_shorthand;
 mod unlinked_file;
@@ -12,7 +14,7 @@ use std::cell::RefCell;
 
 use hir::{
     db::AstDatabase,
-    diagnostics::{Diagnostic as _, DiagnosticCode, DiagnosticSinkBuilder},
+    diagnostics::{AnyDiagnostic, Diagnostic as _, DiagnosticCode, DiagnosticSinkBuilder},
     InFile, Semantics,
 };
 use ide_assists::AssistResolveStrategy;
@@ -42,6 +44,12 @@ pub struct Diagnostic {
 }
 
 impl Diagnostic {
+    fn new(code: &'static str, message: impl Into<String>, range: TextRange) -> Diagnostic {
+        let message = message.into();
+        let code = Some(DiagnosticCode(code));
+        Self { message, range, severity: Severity::Error, fixes: None, unused: false, code }
+    }
+
     fn error(range: TextRange, message: String) -> Self {
         Self { message, range, severity: Severity::Error, fixes: None, unused: false, code: None }
     }
@@ -82,6 +90,13 @@ pub struct DiagnosticsConfig {
     pub disabled: FxHashSet<String>,
 }
 
+struct DiagnosticsContext<'a> {
+    config: &'a DiagnosticsConfig,
+    sema: Semantics<'a, RootDatabase>,
+    #[allow(unused)]
+    resolve: &'a AssistResolveStrategy,
+}
+
 pub(crate) fn diagnostics(
     db: &RootDatabase,
     config: &DiagnosticsConfig,
@@ -108,9 +123,6 @@ pub(crate) fn diagnostics(
     }
     let res = RefCell::new(res);
     let sink_builder = DiagnosticSinkBuilder::new()
-        .on::<hir::diagnostics::UnresolvedModule, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
-        })
         .on::<hir::diagnostics::MissingFields, _>(|d| {
             res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
         })
@@ -204,16 +216,33 @@ pub(crate) fn diagnostics(
             );
         });
 
+    let mut diags = Vec::new();
     let internal_diagnostics = cfg!(test);
     match sema.to_module_def(file_id) {
-        Some(m) => m.diagnostics(db, &mut sink, internal_diagnostics),
+        Some(m) => diags = m.diagnostics(db, &mut sink, internal_diagnostics),
         None => {
             sink.push(UnlinkedFile { file_id, node: SyntaxNodePtr::new(parse.tree().syntax()) });
         }
     }
 
     drop(sink);
-    res.into_inner()
+
+    let mut res = res.into_inner();
+
+    let ctx = DiagnosticsContext { config, sema, resolve };
+    for diag in diags {
+        let d = match diag {
+            AnyDiagnostic::UnresolvedModule(d) => unresolved_module::render(&ctx, &d),
+        };
+        if let Some(code) = d.code {
+            if ctx.config.disabled.contains(code.as_str()) {
+                continue;
+            }
+        }
+        res.push(d)
+    }
+
+    res
 }
 
 fn diagnostic_with_fix<D: DiagnosticWithFixes>(
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
index 258ac6974..8640d7231 100644
--- a/crates/ide/src/diagnostics/fixes.rs
+++ b/crates/ide/src/diagnostics/fixes.rs
@@ -5,7 +5,6 @@ mod create_field;
 mod fill_missing_fields;
 mod remove_semicolon;
 mod replace_with_find_map;
-mod unresolved_module;
 mod wrap_tail_expr;
 
 use hir::{diagnostics::Diagnostic, Semantics};
diff --git a/crates/ide/src/diagnostics/fixes/unresolved_module.rs b/crates/ide/src/diagnostics/unresolved_module.rs
index b3d0283bb..abf53a57c 100644
--- a/crates/ide/src/diagnostics/fixes/unresolved_module.rs
+++ b/crates/ide/src/diagnostics/unresolved_module.rs
@@ -1,39 +1,59 @@
-use hir::{db::AstDatabase, diagnostics::UnresolvedModule, Semantics};
-use ide_assists::{Assist, AssistResolveStrategy};
-use ide_db::{base_db::AnchoredPathBuf, source_change::FileSystemEdit, RootDatabase};
+use hir::db::AstDatabase;
+use ide_assists::Assist;
+use ide_db::{base_db::AnchoredPathBuf, source_change::FileSystemEdit};
 use syntax::AstNode;
 
-use crate::diagnostics::{fix, DiagnosticWithFixes};
+use crate::diagnostics::{fix, Diagnostic, DiagnosticsContext};
 
-impl DiagnosticWithFixes for UnresolvedModule {
-    fn fixes(
-        &self,
-        sema: &Semantics<RootDatabase>,
-        _resolve: &AssistResolveStrategy,
-    ) -> Option<Vec<Assist>> {
-        let root = sema.db.parse_or_expand(self.file)?;
-        let unresolved_module = self.decl.to_node(&root);
-        Some(vec![fix(
-            "create_module",
-            "Create module",
-            FileSystemEdit::CreateFile {
-                dst: AnchoredPathBuf {
-                    anchor: self.file.original_file(sema.db),
-                    path: self.candidate.clone(),
-                },
-                initial_contents: "".to_string(),
-            }
-            .into(),
-            unresolved_module.syntax().text_range(),
-        )])
-    }
+// Diagnostic: unresolved-module
+//
+// This diagnostic is triggered if rust-analyzer is unable to discover referred module.
+pub(super) fn render(ctx: &DiagnosticsContext<'_>, d: &hir::UnresolvedModule) -> Diagnostic {
+    Diagnostic::new(
+        "unresolved-module",
+        "unresolved module",
+        ctx.sema.diagnostics_display_range(d.decl.clone().map(|it| it.into())).range,
+    )
+    .with_fixes(fixes(ctx, d))
+}
+
+fn fixes(ctx: &DiagnosticsContext<'_>, d: &hir::UnresolvedModule) -> Option<Vec<Assist>> {
+    let root = ctx.sema.db.parse_or_expand(d.decl.file_id)?;
+    let unresolved_module = d.decl.value.to_node(&root);
+    Some(vec![fix(
+        "create_module",
+        "Create module",
+        FileSystemEdit::CreateFile {
+            dst: AnchoredPathBuf {
+                anchor: d.decl.file_id.original_file(ctx.sema.db),
+                path: d.candidate.clone(),
+            },
+            initial_contents: "".to_string(),
+        }
+        .into(),
+        unresolved_module.syntax().text_range(),
+    )])
 }
 
 #[cfg(test)]
 mod tests {
     use expect_test::expect;
 
-    use crate::diagnostics::tests::check_expect;
+    use crate::diagnostics::tests::{check_diagnostics, check_expect};
+
+    #[test]
+    fn unresolved_module() {
+        check_diagnostics(
+            r#"
+//- /lib.rs
+mod foo;
+  mod bar;
+//^^^^^^^^ unresolved module
+mod baz {}
+//- /foo.rs
+"#,
+        );
+    }
 
     #[test]
     fn test_unresolved_module_diagnostic() {