If we always add sourceURL even when we have source maps, the native stack gets source mappe

Author: sebmarkbage

packages/react-client/src/ReactFlightClient.js

@@ -1614,10 +1614,6 @@ function resolveErrorDev(
     } else {
       error = callStack();
     }
-    // Overriding the stack isn't really necessary at this point and maybe we should just
-    // leave the native one. However, the native one gets printed unsource mapped with
-    // reportError. If that's fixed it might be better to use the native one.
-    error.stack = stack;
   }
 
   (error: any).digest = digest;
@@ -1723,20 +1719,21 @@ function createFakeFunction<T>(
   // point to the original source.
   let code;
   if (line <= 1) {
-    code = '_=>' + ' '.repeat(col < 4 ? 0 : col - 4) + '_()\n' + comment + '\n';
+    code = '_=>' + ' '.repeat(col < 4 ? 0 : col - 4) + '_()\n' + comment;
   } else {
     code =
       comment +
       '\n'.repeat(line - 2) +
       '_=>\n' +
       ' '.repeat(col < 1 ? 0 : col - 1) +
-      '_()\n';
+      '_()';
   }
 
+  if (filename) {
+    code += '\n//# sourceURL=' + filename;
+  }
   if (sourceMap) {
-    code += '//# sourceMappingURL=' + sourceMap;
-  } else if (filename) {
-    code += '//# sourceURL=' + filename;
+    code += '\n//# sourceMappingURL=' + sourceMap;
   }
 
   let fn: FakeFunction<T>;