Remove part of FURB131 (#239):

This PR removes a portion of FURB131 which suggested replacing most instances
of `del` with `.pop()`. The reasoning behid it was not well founded, and in
most cases, it is better to just leave the `del` statememt as it is. In one
instance though, which is the `del x[:]` usage, it is more preferable to use
the `.clear()` method, as it is faster and more readable.

Closes #234.

docs/checks.md

@@ -757,21 +757,18 @@ if "key" in d:
 
 Categories: `builtin` `readability`
 
-The `del` statement has it's uses, but for the most part, it can be
-replaced with a more flexible and expressive alternative.
-
-With `dict` and `list` types you can remove a key/index by using the
-`.pop()` method. If you want to remove all the elements in a `dict` or
-`list`, use `.clear()` instead.
+The `del` statement is commonly used for popping single elements from dicts
+and lists, though a slice can be used to remove a range of elements
+instead. When removing all elements via a slice, use the faster and more
+succinct `.clear()` method instead.
 
 Bad:
 
 ```python
 names = {"key": "value"}
 nums = [1, 2, 3]
 
-del names["key"]
-del nums[0]
+del names[:]
 del nums[:]
 ```
 
@@ -781,8 +778,7 @@ Good:
 names = {"key": "value"}
 nums = [1, 2, 3]
 
-names.pop("key")
-nums.pop(0)
+names.clear()
 nums.clear()
 ```
 ## FURB132: `use-set-discard`

refurb/checks/builtin/no_del.py

@@ -8,21 +8,18 @@
 @dataclass
 class ErrorInfo(Error):
     """
-    The `del` statement has it's uses, but for the most part, it can be
-    replaced with a more flexible and expressive alternative.
-
-    With `dict` and `list` types you can remove a key/index by using the
-    `.pop()` method. If you want to remove all the elements in a `dict` or
-    `list`, use `.clear()` instead.
+    The `del` statement is commonly used for popping single elements from dicts
+    and lists, though a slice can be used to remove a range of elements
+    instead. When removing all elements via a slice, use the faster and more
+    succinct `.clear()` method instead.
 
     Bad:
 
     ```
     names = {"key": "value"}
     nums = [1, 2, 3]
 
-    del names["key"]
-    del nums[0]
+    del names[:]
     del nums[:]
     ```
 
@@ -32,15 +29,15 @@ class ErrorInfo(Error):
     names = {"key": "value"}
     nums = [1, 2, 3]
 
-    names.pop("key")
-    nums.pop(0)
+    names.clear()
     nums.clear()
     ```
     """
 
     name = "no-del"
     code = 131
     categories = ["builtin", "readability"]
+    msg: str = "Replace `del x[:]` with `x.clear()`"
 
 
 def check(node: DelStmt, errors: list[Error]) -> None:
@@ -50,18 +47,4 @@ def check(node: DelStmt, errors: list[Error]) -> None:
         ) if str(ty).startswith(("builtins.dict[", "builtins.list[")):
             match index:
                 case SliceExpr(begin_index=None, end_index=None):
-                    errors.append(
-                        ErrorInfo.from_node(
-                            node, "Replace `del x[:]` with `x.clear()`"
-                        )
-                    )
-
-                case SliceExpr():
-                    pass
-
-                case _:
-                    errors.append(
-                        ErrorInfo.from_node(
-                            node, "Replace `del x[y]` with `x.pop(y)`"
-                        )
-                    )
+                    errors.append(ErrorInfo.from_node(node))

test/data/err_131.py

@@ -3,13 +3,14 @@
 
 # these should match
 
-del names["key"]
-del nums[0]
 del nums[:]
 
 
 # these should not
 
+del names["key"]
+del nums[0]
+
 x = 1
 del x
 

test/data/err_131.txt

@@ -1,3 +1 @@
-test/data/err_131.py:6:1 [FURB131]: Replace `del x[y]` with `x.pop(y)`
-test/data/err_131.py:7:1 [FURB131]: Replace `del x[y]` with `x.pop(y)`
-test/data/err_131.py:8:1 [FURB131]: Replace `del x[:]` with `x.clear()`
+test/data/err_131.py:6:1 [FURB131]: Replace `del x[:]` with `x.clear()`