fallback to normal resolving if alias doesn't resolve

crates/turbopack-core/src/resolve/mod.rs

@@ -1513,7 +1513,9 @@ async fn resolve_internal_inline(
                 // Typescript resolution algorithm does in case an alias match
                 // doesn't resolve to anything: fall back to resolving the request normally.
                 if let Some(result) = resolved_result {
-                    return Ok(result);
+                    if !*result.is_unresolveable().await? {
+                        return Ok(result);
+                    }
                 }
             }
         }

crates/turbopack-tests/tests/execution/turbopack/resolving/tsconfig-fallback/input/index.js

@@ -0,0 +1,24 @@
+import foo from "@foo";
+import fooBar from "@foo/bar";
+import bazFoo from "@baz/foo";
+import srcBazFoo from "@src/baz/foo";
+
+it("should resolve an alias to a local file", () => {
+  expect(foo).toBe("foo");
+  expect(require("@foo")).toHaveProperty("default", "foo");
+});
+
+it("should fallback from an alias", () => {
+  expect(fooBar).toBe("@foo/bar");
+  expect(require("@foo/bar")).toHaveProperty("default", "@foo/bar");
+});
+
+it("should prefer alias over normal resolving", () => {
+  expect(bazFoo).toBe("baz/foo");
+  expect(require("@baz/foo")).toHaveProperty("default", "baz/foo");
+});
+
+it("should resolve the alternative alias value", () => {
+  expect(srcBazFoo).toBe("baz/foo");
+  expect(require("@src/baz/foo")).toHaveProperty("default", "baz/foo");
+});

crates/turbopack-tests/tests/execution/turbopack/resolving/tsconfig-fallback/input/src/baz/foo.ts

@@ -0,0 +1 @@
+export default "baz/foo";

crates/turbopack-tests/tests/execution/turbopack/resolving/tsconfig-fallback/input/src/foo.ts

@@ -0,0 +1 @@
+export default "foo";

crates/turbopack-tests/tests/execution/turbopack/resolving/tsconfig-fallback/input/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "compilerOptions": {
+    "paths": {
+      "@*": ["./src/*", "./*"]
+    }
+  }
+}