[perflint] fix invalid hoist in perf401 (#14369)

Co-authored-by: Micha Reiser <[email protected]>

Author: w0nder1ng

crates/ruff_linter/resources/test/fixtures/perflint/PERF401.py

@@ -74,49 +74,57 @@ def f():
         result.append(i)  # Ok
 
 
-def f():
+async def f():
     items = [1, 2, 3, 4]
     result = []
     async for i in items:
         if i % 2:
             result.append(i)  # PERF401
 
 
-def f():
+async def f():
     items = [1, 2, 3, 4]
     result = []
     async for i in items:
         result.append(i)  # PERF401
 
 
+async def f():
+    items = [1, 2, 3, 4]
+    result = [1, 2]
+    async for i in items:
+        result.append(i)  # PERF401
+
+
 def f():
-    result, _ = [1,2,3,4], ...
+    result, _ = [1, 2, 3, 4], ...
     for i in range(10):
-        result.append(i*2)  # PERF401
+        result.append(i * 2)  # PERF401
 
 
 def f():
     result = []
     if True:
         for i in range(10):  # single-line comment 1 should be protected
             # single-line comment 2 should be protected
-            if i % 2: # single-line comment 3 should be protected 
-                result.append(i) # PERF401
+            if i % 2:  # single-line comment 3 should be protected
+                result.append(i)  # PERF401
 
 
 def f():
-    result = [] # comment after assignment should be protected
+    result = []  # comment after assignment should be protected
     for i in range(10):  # single-line comment 1 should be protected
         # single-line comment 2 should be protected
-        if i % 2: # single-line comment 3 should be protected 
-            result.append(i) # PERF401
+        if i % 2:  # single-line comment 3 should be protected
+            result.append(i)  # PERF401
 
 
 def f():
     result = []
     for i in range(10):
         """block comment stops the fix"""
-        result.append(i*2)  # Ok
+        result.append(i * 2)  # Ok
+
 
 def f(param):
     # PERF401
@@ -125,3 +133,107 @@ def f(param):
         new_layers = []
         for value in param:
             new_layers.append(value * 3)
+
+
+def f():
+    result = []
+    var = 1
+    for _ in range(10):
+        result.append(var + 1)  # PERF401
+
+
+def f():
+    # make sure that `tmp` is not deleted
+    tmp = 1; result = []  # commment should be protected
+    for i in range(10):
+        result.append(i + 1)  # PERF401
+
+
+def f():
+    # make sure that `tmp` is not deleted
+    result = []; tmp = 1  # commment should be protected
+    for i in range(10):
+        result.append(i + 1)  # PERF401
+
+
+def f():
+    result = []  # comment should be protected
+    for i in range(10):
+        result.append(i * 2)  # PERF401
+
+
+def f():
+    result = []
+    result.append(1)
+    for i in range(10):
+        result.append(i * 2)  # PERF401
+
+
+def f():
+    result = []
+    result += [1]
+    for i in range(10):
+        result.append(i * 2)  # PERF401
+
+
+def f():
+    result = []
+    for val in range(5):
+        result.append(val * 2)  # Ok
+    print(val)
+
+
+def f():
+    result = []
+    for val in range(5):
+        result.append(val * 2)  # PERF401
+    val = 1
+    print(val)
+
+
+def f():
+    i = [1, 2, 3]
+    result = []
+    for i in i:
+        result.append(i + 1)  # PERF401
+
+
+def f():
+    result = []
+    for i in range(  # Comment 1 should not be duplicated
+        (
+            2  # Comment 2
+            + 1
+        )
+    ):  # Comment 3
+        if i % 2:  # Comment 4
+            result.append(
+                (
+                    i + 1,
+                    # Comment 5
+                    2,
+                )
+            )  # PERF401
+
+
+def f():
+    result: list[int] = []
+    for i in range(10):
+        result.append(i * 2)  # PERF401
+
+
+def f():
+    a, b = [1, 2, 3], [4, 5, 6]
+    result = []
+    for i in a, b:
+        result.append(i[0] + i[1])  # PERF401
+    return result
+
+
+def f():
+    values = [1, 2, 3]
+    result = []
+    for a in values:
+        print(a)
+    for a in values:
+        result.append(a + 1)  # PERF401

crates/ruff_linter/src/checkers/ast/analyze/deferred_for_loops.rs

@@ -14,7 +14,6 @@ pub(crate) fn deferred_for_loops(checker: &mut Checker) {
             let Stmt::For(stmt_for) = checker.semantic.current_statement() else {
                 unreachable!("Expected Stmt::For");
             };
-
             if checker.enabled(Rule::UnusedLoopControlVariable) {
                 flake8_bugbear::rules::unused_loop_control_variable(checker, stmt_for);
             }
@@ -36,6 +35,9 @@ pub(crate) fn deferred_for_loops(checker: &mut Checker) {
             if checker.enabled(Rule::DictIndexMissingItems) {
                 pylint::rules::dict_index_missing_items(checker, stmt_for);
             }
+            if checker.enabled(Rule::ManualListComprehension) {
+                perflint::rules::manual_list_comprehension(checker, stmt_for);
+            }
         }
     }
 }

crates/ruff_linter/src/checkers/ast/analyze/statement.rs

@@ -1366,6 +1366,7 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
                 Rule::UnnecessaryEnumerate,
                 Rule::UnusedLoopControlVariable,
                 Rule::YieldInForLoop,
+                Rule::ManualListComprehension,
             ]) {
                 checker.analyze.for_loops.push(checker.semantic.snapshot());
             }
@@ -1390,9 +1391,6 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.enabled(Rule::DictIterMissingItems) {
                 pylint::rules::dict_iter_missing_items(checker, target, iter);
             }
-            if checker.enabled(Rule::ManualListComprehension) {
-                perflint::rules::manual_list_comprehension(checker, for_stmt);
-            }
             if checker.enabled(Rule::ManualListCopy) {
                 perflint::rules::manual_list_copy(checker, for_stmt);
             }