1 files changed, 87 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..81244b293
--- /dev/null
+++ b/crates/ide/src/diagnostics/fixes/unresolved_module.rs
@@ -0,0 +1,87 @@
+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, DiagnosticWithFix};
+
+impl DiagnosticWithFix for UnresolvedModule {
+    fn fix(
+        &self,
+        sema: &Semantics<RootDatabase>,
+        _resolve: &AssistResolveStrategy,
+    ) -> Option<Assist> {
+        let root = sema.db.parse_or_expand(self.file)?;
+        let unresolved_module = self.decl.to_node(&root);
+        Some(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,
+                        fix: 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",
+                            ),
+                        ),
+                    },
+                ]
+            "#]],
+        );
+    }
+}