1 files changed, 89 insertions, 0 deletions

diff --git a/crates/ide/src/diagnostics/fixes/unresolved_module.rs b/crates/ide/src/diagnostics/fixes/unresolved_module.rs
new file mode 100644
index 000000000..b3d0283bb
--- /dev/null
+++ b/crates/ide/src/diagnostics/fixes/unresolved_module.rs
@@ -0,0 +1,89 @@
+use hir::{db::AstDatabase, diagnostics::UnresolvedModule, Semantics};
+use ide_assists::{Assist, AssistResolveStrategy};
+use ide_db::{base_db::AnchoredPathBuf, source_change::FileSystemEdit, RootDatabase};
+use syntax::AstNode;
+
+use crate::diagnostics::{fix, DiagnosticWithFixes};
+
+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(),
+        )])
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use expect_test::expect;
+
+    use crate::diagnostics::tests::check_expect;
+
+    #[test]
+    fn test_unresolved_module_diagnostic() {
+        check_expect(
+            r#"mod foo;"#,
+            expect![[r#"
+                [
+                    Diagnostic {
+                        message: "unresolved module",
+                        range: 0..8,
+                        severity: Error,
+                        fixes: Some(
+                            [
+                                Assist {
+                                    id: AssistId(
+                                        "create_module",
+                                        QuickFix,
+                                    ),
+                                    label: "Create module",
+                                    group: None,
+                                    target: 0..8,
+                                    source_change: Some(
+                                        SourceChange {
+                                            source_file_edits: {},
+                                            file_system_edits: [
+                                                CreateFile {
+                                                    dst: AnchoredPathBuf {
+                                                        anchor: FileId(
+                                                            0,
+                                                        ),
+                                                        path: "foo.rs",
+                                                    },
+                                                    initial_contents: "",
+                                                },
+                                            ],
+                                            is_snippet: false,
+                                        },
+                                    ),
+                                },
+                            ],
+                        ),
+                        unused: false,
+                        code: Some(
+                            DiagnosticCode(
+                                "unresolved-module",
+                            ),
+                        ),
+                    },
+                ]
+            "#]],
+        );
+    }
+}