Add more cases to FURB173

refurb/checks/readability/no_unnecessary_cast.py

@@ -1,6 +1,7 @@
 from dataclasses import dataclass
 
 from mypy.nodes import (
+    ArgKind,
     BytesExpr,
     CallExpr,
     ComplexExpr,
@@ -83,7 +84,8 @@ def check(node: CallExpr, errors: list[Error]) -> None:
         case CallExpr(
             callee=NameExpr(fullname=fullname, name=name),
             args=[arg],
-        ) if fullname in FUNC_NAMES:
+            arg_kinds=[arg_kind],
+        ) if arg_kind != ArgKind.ARG_STAR2 and fullname in FUNC_NAMES:
             node_type, msg = FUNC_NAMES[fullname]
 
             if type(arg) == node_type:

refurb/checks/readability/use_dict_union.py

@@ -1,8 +1,9 @@
 from dataclasses import dataclass
 from itertools import groupby
 
-from mypy.nodes import DictExpr, Expression, RefExpr, Var
+from mypy.nodes import ArgKind, CallExpr, DictExpr, Expression, RefExpr, Var
 
+from refurb.checks.common import stringify
 from refurb.error import Error
 from refurb.settings import Settings
 
@@ -55,7 +56,7 @@ def is_builtin_mapping(expr: Expression) -> bool:
     return False
 
 
-def check(node: DictExpr, errors: list[Error], settings: Settings) -> None:
+def check(node: DictExpr | CallExpr, errors: list[Error], settings: Settings) -> None:
     if settings.get_python_version() < (3, 9):
         return  # pragma: no cover
 
@@ -107,3 +108,60 @@ def check(node: DictExpr, errors: list[Error], settings: Settings) -> None:
             msg = f"Replace `{{{old_msg}}}` with `{new_msg}`"
 
             errors.append(ErrorInfo.from_node(node, msg))
+
+        case CallExpr(callee=RefExpr(fullname="builtins.dict")):
+            old = []
+            args: list[str] = []
+            kwargs: dict[str, str] = {}
+
+            # ignore dict(x) since that is covered by FURB123
+            match node.arg_kinds:
+                case []:
+                    return
+
+                case [ArgKind.ARG_POS]:
+                    return
+
+            # TODO: move dict(a=1, b=2) to FURB112
+            if all(x == ArgKind.ARG_NAMED for x in node.arg_kinds):
+                return
+
+            for arg, name, kind in zip(node.args, node.arg_names, node.arg_kinds):
+                # ignore dict(*x)
+                if kind == ArgKind.ARG_STAR:
+                    return
+
+                if kind == ArgKind.ARG_STAR2:
+                    old.append(f"**{stringify(arg)}")
+
+                    stringified_arg = stringify(arg)
+
+                    if len(node.args) == 1:
+                        # TODO: dict(**x) can be replaced with x.copy() if we know x has a copy()
+                        # method.
+                        stringified_arg = f"{{**{stringified_arg}}}"
+
+                    args.append(stringified_arg)
+
+                elif name:
+                    old.append(f"{name}={stringify(arg)}")
+                    kwargs[name] = stringify(arg)
+
+                else:
+                    old.append(stringify(arg))
+                    args.append(stringify(arg))
+
+            inner = ", ".join(old)
+            old_msg = f"dict({inner})"
+
+            if kwargs:
+                kwargs2 = ", ".join(f'"{name}": {expr}' for name, expr in kwargs.items())
+                kwargs2 = f"{{{kwargs2}}}"
+
+                args.append(kwargs2)
+
+            new_msg = " | ".join(args)
+
+            msg = f"Replace `{old_msg}` with `{new_msg}`"
+
+            errors.append(ErrorInfo.from_node(node, msg))

test/data/err_123.py

@@ -46,3 +46,4 @@
 _ = str(123)
 _ = tuple([1, 2, 3])
 _ = int("0xFF")
+_ = dict(**d)  # noqa: FURB173

test/data/err_173.py

@@ -34,6 +34,14 @@
 _ = {"k": "v", **userdict}
 
 
+_ = dict(**x)
+_ = dict(x, **y)
+_ = dict(**x, **y)
+_ = dict(x, a=1)
+_ = dict(**x, a=1, b=2)
+_ = dict(**x, **y, a=1, b=2)
+
+
 # these should not
 
 _ = {}
@@ -60,3 +68,9 @@ def __getitem__(self, key: str) -> Any:
 
 # TODO: support more expr types
 _ = {"k": "v", **{}}
+
+
+_ = dict(x)  # noqa: FURB123
+_ = dict(*({},))
+_ = dict()  # noqa: FURB112
+_ = dict(a=1, b=2)

test/data/err_173.txt

@@ -14,3 +14,9 @@ test/data/err_173.py:25:5 [FURB173]: Replace `{..., **x1}` with `{...} | x1`
 test/data/err_173.py:28:5 [FURB173]: Replace `{..., **x1}` with `{...} | x1`
 test/data/err_173.py:31:5 [FURB173]: Replace `{..., **x1}` with `{...} | x1`
 test/data/err_173.py:34:5 [FURB173]: Replace `{..., **x1}` with `{...} | x1`
+test/data/err_173.py:37:5 [FURB173]: Replace `dict(**x)` with `{**x}`
+test/data/err_173.py:38:5 [FURB173]: Replace `dict(x, **y)` with `x | y`
+test/data/err_173.py:39:5 [FURB173]: Replace `dict(**x, **y)` with `x | y`
+test/data/err_173.py:40:5 [FURB173]: Replace `dict(x, a=1)` with `x | {"a": 1}`
+test/data/err_173.py:41:5 [FURB173]: Replace `dict(**x, a=1, b=2)` with `x | {"a": 1, "b": 2}`
+test/data/err_173.py:42:5 [FURB173]: Replace `dict(**x, **y, a=1, b=2)` with `x | y | {"a": 1, "b": 2}`