[bugfix] fix an warning error in MNLI loader

fastNLP/io/loader/matching.py

@@ -56,7 +56,6 @@ class MNLILoader(Loader):
         with open(path, 'r', encoding='utf-8') as f:
             f.readline()  # 跳过header
             if path.endswith("test_matched.tsv") or path.endswith('test_mismatched.tsv'):
-                warnings.warn("RTE's test file has no target.")
                 warnings.warn("MNLI's test file has no target.")
                 for line in f:
                     line = line.strip()
@@ -64,8 +63,9 @@ class MNLILoader(Loader):
                         parts = line.split('\t')
                         raw_words1 = parts[8]
                         raw_words2 = parts[9]
+                        idx = int(parts[0])
                         if raw_words1 and raw_words2:
-                            ds.append(Instance(raw_words1=raw_words1, raw_words2=raw_words2))
+                            ds.append(Instance(raw_words1=raw_words1, raw_words2=raw_words2, index=idx))
             else:
                 for line in f:
                     line = line.strip()
@@ -74,8 +74,9 @@ class MNLILoader(Loader):
                         raw_words1 = parts[8]
                         raw_words2 = parts[9]
                         target = parts[-1]
+                        idx = int(parts[0])
                         if raw_words1 and raw_words2 and target:
-                            ds.append(Instance(raw_words1=raw_words1, raw_words2=raw_words2, target=target))
+                            ds.append(Instance(raw_words1=raw_words1, raw_words2=raw_words2, target=target, index=idx))
         return ds
     
     def load(self, paths: str = None):