From eaf2a35753b8bb3777d455be8e336a3072887f16 Mon Sep 17 00:00:00 2001
From: Eric Eastwood <contact@ericeastwood.com>
Date: Wed, 5 Jun 2024 19:27:10 -0500
Subject: [PATCH] Fix shadowed cases

---
 .../control_var_used_after_block.py           | 74 ++-----------------
 .../rules/control_var_used_after_block.rs     | 27 +++++--
 crates/ruff_python_semantic/src/model.rs      |  6 ++
 3 files changed, 34 insertions(+), 73 deletions(-)

diff --git a/crates/ruff_linter/resources/test/fixtures/wemake_python_styleguide/control_var_used_after_block.py b/crates/ruff_linter/resources/test/fixtures/wemake_python_styleguide/control_var_used_after_block.py
index 5f72ae16eca12..b38843cea6bea 100644
--- a/crates/ruff_linter/resources/test/fixtures/wemake_python_styleguide/control_var_used_after_block.py
+++ b/crates/ruff_linter/resources/test/fixtures/wemake_python_styleguide/control_var_used_after_block.py
@@ -1,70 +1,8 @@
-import typing
-from typing import cast
-
-for global_var in []:
-    _ = global_var
+for x in []:
+    _ = x
     pass
 
-_ = global_var
-
-def foo():
-    # For control var used outside block
-    for event in []:
-        _ = event
-        pass
-
-    _ = event
-
-    for x in range(10):
-        pass
-
-    # Usage in another block
-    for y in range(10):
-        # x is used outside of the loop it was defined in (meant to use y)
-        if x == 5:
-            pass
-
-    # Tuple destructuring
-    for a, b, c in []:
-        _ = a
-        _ = b
-        _ = c
-        pass
-
-    _ = a
-    _ = b
-    _ = c
-
-    # Array destructuring
-    for [d, e, f] in []:
-        _ = d
-        _ = e
-        _ = f
-        pass
-
-    _ = d
-    _ = e
-    _ = f
-
-    # with statement
-    with None as w:
-        _ = w
-        pass
-
-    _ = w
-
-    # Nested blocks
-    with None as q:
-        _ = q
-        
-        for n in []:
-            _ = n
-            _ = q
-            pass
-
-        _ = n
-
-    _ = q
-    _ = n
-
-
+# Using the same control variable name in a different loop is ok
+for x in []:
+    _ = x
+    pass
diff --git a/crates/ruff_linter/src/rules/wemake_python_styleguide/rules/control_var_used_after_block.rs b/crates/ruff_linter/src/rules/wemake_python_styleguide/rules/control_var_used_after_block.rs
index 1864b8a888db5..de500545874c3 100644
--- a/crates/ruff_linter/src/rules/wemake_python_styleguide/rules/control_var_used_after_block.rs
+++ b/crates/ruff_linter/src/rules/wemake_python_styleguide/rules/control_var_used_after_block.rs
@@ -3,7 +3,7 @@ use std::fmt;
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::Stmt;
-use ruff_python_semantic::{NodeId, Scope};
+use ruff_python_semantic::{BindingId, NodeId, Scope};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -76,11 +76,22 @@ pub(crate) fn control_var_used_after_block(
     scope: &Scope,
     diagnostics: &mut Vec<Diagnostic>,
 ) {
+    println!("nodes {:#?}", checker.semantic().nodes());
+
+    // Keep track of node_ids we know are used in the same block. This helps us when
+    // people use the same variable name in multiple blocks.
+    let mut known_good_reference_node_ids: Vec<NodeId> = Vec::new();
+
+    let all_bindings: Vec<(&str, BindingId)> = scope.all_bindings().collect();
+    let reversed_bindings = all_bindings.iter().rev();
+
     // Find for-loop and with-statement variable bindings
-    for (name, binding) in scope
-        .bindings()
-        .map(|(name, binding_id)| (name, checker.semantic().binding(binding_id)))
+    for (&name, binding) in reversed_bindings
+        .map(|(name, binding_id)| (name, checker.semantic().binding(*binding_id)))
         .filter_map(|(name, binding)| {
+            if !binding.kind.is_builtin() {
+                println!("name {:?} binding.kind {:?}", name, binding.kind);
+            }
             if binding.kind.is_loop_var() || binding.kind.is_with_item_var() {
                 return Some((name, binding));
             }
@@ -108,12 +119,18 @@ pub(crate) fn control_var_used_after_block(
             for ancestor_node_id in statement_hierarchy {
                 if binding_statement_id == ancestor_node_id {
                     is_used_in_block = true;
+                    known_good_reference_node_ids.push(reference_node_id);
                     break;
                 }
             }
 
+            println!(
+                "is_used_in_block {:?} binding_source_node_id {:?} binding_statement_id {:?} current_reference_node_id {:?} known_good_reference_node_ids {:?}",
+                is_used_in_block, binding_source_node_id, binding_statement_id, reference_node_id, known_good_reference_node_ids
+            );
+
             // If the reference wasn't used in the same block, report a violation/diagnostic
-            if !is_used_in_block {
+            if !is_used_in_block && !known_good_reference_node_ids.contains(&reference_node_id) {
                 let block_kind = match binding_statement {
                     Stmt::For(_) => BlockKind::For,
                     Stmt::With(_) => BlockKind::With,
diff --git a/crates/ruff_python_semantic/src/model.rs b/crates/ruff_python_semantic/src/model.rs
index 06cf6f4de1f7c..b076f80537461 100644
--- a/crates/ruff_python_semantic/src/model.rs
+++ b/crates/ruff_python_semantic/src/model.rs
@@ -1144,6 +1144,12 @@ impl<'a> SemanticModel<'a> {
         None
     }
 
+    /// TODO
+    #[inline]
+    pub fn nodes(&self) -> &Nodes<'a> {
+        &self.nodes
+    }
+
     /// Return the [`Stmt`] corresponding to the given [`NodeId`].
     #[inline]
     pub fn node(&self, node_id: NodeId) -> &NodeRef<'a> {