Improve FURB111, bump version (#285):

Add support for detecting lambdas returning `[]`, `{}`, and `()` which can be
replaced with the `list`, `dict`, and `tuple` functions instead.

Also bump package version for update.

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "refurb"
-version = "1.20.0"
+version = "1.21.0"
 description = "A tool for refurbish and modernize Python codebases"
 authors = ["dosisod"]
 license = "GPL-3.0-only"

refurb/checks/readability/use_func_name.py

@@ -5,10 +5,13 @@
     Argument,
     Block,
     CallExpr,
+    DictExpr,
     Expression,
     LambdaExpr,
+    ListExpr,
     NameExpr,
     ReturnStmt,
+    TupleExpr,
 )
 
 from refurb.error import Error
@@ -76,3 +79,32 @@ def check(node: LambdaExpr, errors: list[Error]) -> None:
                     f"Replace `{_lambda}: {func_name}({arg_names})` with `{func_name}`",  # noqa: E501
                 )
             )
+
+        case LambdaExpr(
+            arguments=[],
+            body=Block(
+                body=[
+                    ReturnStmt(
+                        expr=ListExpr(items=[])
+                        | DictExpr(items=[])
+                        | TupleExpr(items=[]) as expr,
+                    )
+                ],
+            ),
+        ):
+            if isinstance(expr, ListExpr):
+                old = "[]"
+                new = "list"
+            elif isinstance(expr, DictExpr):
+                old = "{}"
+                new = "dict"
+            else:
+                old = "()"
+                new = "tuple"
+
+            errors.append(
+                ErrorInfo.from_node(
+                    node,
+                    f"Replace `lambda: {old}` with `{new}`",
+                )
+            )

test/data/err_111.py

@@ -8,6 +8,10 @@ def f(x, y):
 lambda x: bool(x)
 lambda x, y: f(x, y)
 
+lambda: []
+lambda: {}
+lambda: ()
+
 
 # these will not
 
@@ -19,3 +23,7 @@ def f(x, y):
 lambda x: print(*x)
 lambda x: print(**x)
 lambda: True
+
+lambda: [1, 2, 3]
+lambda: {"k": "v"}
+lambda: (1, 2, 3)

test/data/err_111.txt

@@ -1,3 +1,6 @@
 test/data/err_111.py:7:1 [FURB111]: Replace `lambda: print()` with `print`
 test/data/err_111.py:8:1 [FURB111]: Replace `lambda x: bool(x)` with `bool`
 test/data/err_111.py:9:1 [FURB111]: Replace `lambda x, y: f(x, y)` with `f`
+test/data/err_111.py:11:1 [FURB111]: Replace `lambda: []` with `list`
+test/data/err_111.py:12:1 [FURB111]: Replace `lambda: {}` with `dict`
+test/data/err_111.py:13:1 [FURB111]: Replace `lambda: ()` with `tuple`