Add better type deduction for sets, frozensets, and tuples to FURB115

dosisod · Mar 8, 2024 · d4e9ee3 · d4e9ee3
1 parent ae0e502
commit d4e9ee3
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Showing 3 changed files with 34 additions and 3 deletions.
diff --git a/refurb/checks/readability/no_len_cmp.py b/refurb/checks/readability/no_len_cmp.py
@@ -17,11 +17,19 @@
     NameExpr,
     Node,
     OpExpr,
+    TupleExpr,
     UnaryExpr,
     WhileStmt,
 )
 
-from refurb.checks.common import is_mapping, is_sized, stringify
+from refurb.checks.common import (
+    get_mypy_type,
+    is_mapping,
+    is_same_type,
+    is_sized,
+    mypy_type_to_python_type,
+    stringify,
+)
 from refurb.error import Error
 from refurb.visitor import METHOD_NODE_MAPPINGS, TraverserVisitor
 
@@ -139,8 +147,19 @@ def visit_comparison_expr(self, node: ComparisonExpr) -> None:
 
             case ComparisonExpr(
                 operators=["==" | "!=" as oper],
-                operands=[lhs, (ListExpr(items=[]) | DictExpr(items=[]))],
-            ) if is_sized(lhs):
+                operands=[
+                    lhs,
+                    (
+                        ListExpr(items=[])
+                        | DictExpr(items=[])
+                        | TupleExpr(items=[])
+                        | CallExpr(
+                            callee=NameExpr(fullname="builtins.set" | "builtins.frozenset"),
+                            args=[],
+                        )
+                    ) as rhs,
+                ],
+            ) if is_same_type(get_mypy_type(lhs), mypy_type_to_python_type(get_mypy_type(rhs))):
                 old = stringify(node)
                 new = stringify(lhs)
 

diff --git a/test/data/err_115.py b/test/data/err_115.py
@@ -98,6 +98,11 @@ def mapping_check(m: Mapping[str, str]):
 assert len(authors) == 0
 
 
+assert fruits == frozenset()
+assert primes == set()
+assert data == ()
+
+
 # these should not
 
 if len(nums) == 1: ...
@@ -127,3 +132,7 @@ def __len__(self) -> int:
 assert nums <= []
 
 assert len(nums) % 2
+
+assert data == []
+assert data == {}
+assert data == set()
diff --git a/test/data/err_115.txt b/test/data/err_115.txt
@@ -45,3 +45,6 @@ test/data/err_115.py:95:8 [FURB115]: Replace `len(list(authors)) == 0` with `not
 test/data/err_115.py:96:8 [FURB115]: Replace `len(authors.keys()) == 0` with `not authors`
 test/data/err_115.py:97:8 [FURB115]: Replace `len(authors.values()) == 0` with `not authors`
 test/data/err_115.py:98:8 [FURB115]: Replace `len(authors) == 0` with `not authors`
+test/data/err_115.py:101:8 [FURB115]: Replace `fruits == frozenset()` with `not fruits`
+test/data/err_115.py:102:8 [FURB115]: Replace `primes == set()` with `not primes`
+test/data/err_115.py:103:8 [FURB115]: Replace `data == ()` with `not data`