account for calling start with 0 or negative num

doc/whatsnew/fragments/7682.bugfix

@@ -1,3 +1,3 @@
-``unnecessary-list-index-lookup`` will not be emitted if ``enumerate`` is called with a `start` arg or kwarg.
+``unnecessary-list-index-lookup`` will not be wrongly emitted if ``enumerate`` is called with ``start``.
 
 Closes #7682

pylint/checkers/refactoring/refactoring_checker.py

@@ -2206,13 +2206,37 @@ def _check_unnecessary_list_index_lookup(
             )
 
     def _enumerate_with_start(self, node: nodes.For | nodes.Comprehension) -> bool:
-        """Check presence of `start` kwarg or second argument to enumerate
-        For example
+        """Check presence of `start` kwarg or second argument to enumerate.
+
+        For example:
+
         `enumerate([1,2,3], start=1)`
         `enumerate([1,2,3], 1)`
+
+        If `start` is assigned to `0`, the default value, this is equivalent to
+        not calling `enumerate` with start.
         """
         if len(node.iter.args) > 1:
-            # We assume the second argument to `enumerate` is the `start` arg.
-            return True
+            # We assume the second argument to `enumerate` is the `start` int arg.
+            # It's a reasonable assumption for now as it's the only possible argument:
+            # https://docs.python.org/3/library/functions.html#enumerate
+            start_arg = node.iter.args[1]
+
+            start_val = (
+                start_arg.operand.value
+                if isinstance(start_arg, nodes.UnaryOp)
+                else start_arg.value
+            )
+            return not start_val == 0
+
+        for keyword in node.iter.keywords:
+            if keyword.arg == "start":
+                start_val = (
+                    keyword.value.operand.value
+                    if isinstance(keyword.value, nodes.UnaryOp)
+                    else keyword.value.value
+                )
 
-        return any(keyword.arg == "start" for keyword in node.iter.keywords)
+                return not start_val == 0
+
+        return False

tests/functional/u/unnecessary/unnecessary_list_index_lookup.py

@@ -97,4 +97,19 @@ def process_list_again(data):
 ]
 
 for idx, val in enumerate(series, start=2):
-    print(my_list[idx])
+    print(series[idx])
+
+for idx, val in enumerate(series, 2):
+    print(series[idx])
+
+for idx, val in enumerate(series, start=-2):
+    print(series[idx])
+
+for idx, val in enumerate(series, -2):
+    print(series[idx])
+
+for idx, val in enumerate(series, start=0):
+    print(series[idx])  # [unnecessary-list-index-lookup]
+
+for idx, val in enumerate(series, 0):
+    print(series[idx])  # [unnecessary-list-index-lookup]

tests/functional/u/unnecessary/unnecessary_list_index_lookup.txt

@@ -2,3 +2,5 @@ unnecessary-list-index-lookup:8:10:8:22::Unnecessary list index lookup, use 'val
 unnecessary-list-index-lookup:43:52:43:64::Unnecessary list index lookup, use 'val' instead:HIGH
 unnecessary-list-index-lookup:46:10:46:22::Unnecessary list index lookup, use 'val' instead:HIGH
 unnecessary-list-index-lookup:74:10:74:27::Unnecessary list index lookup, use 'val' instead:HIGH
+unnecessary-list-index-lookup:112:10:112:21::Unnecessary list index lookup, use 'val' instead:HIGH
+unnecessary-list-index-lookup:115:10:115:21::Unnecessary list index lookup, use 'val' instead:HIGH