Avoid PD false positives on some non-DataFrame expressions (#1538)

src/ast/helpers.rs

@@ -212,6 +212,23 @@ pub fn is_constant_non_singleton(expr: &Expr) -> bool {
     is_constant(expr) && !is_singleton(expr)
 }
 
+/// Return `true` if an `Expr` is not a reference to a variable (or something
+/// that could resolve to a variable, like a function call).
+pub fn is_non_variable(expr: &Expr) -> bool {
+    matches!(
+        expr.node,
+        ExprKind::Constant { .. }
+            | ExprKind::Tuple { .. }
+            | ExprKind::List { .. }
+            | ExprKind::Set { .. }
+            | ExprKind::Dict { .. }
+            | ExprKind::SetComp { .. }
+            | ExprKind::ListComp { .. }
+            | ExprKind::DictComp { .. }
+            | ExprKind::GeneratorExp { .. }
+    )
+}
+
 /// Return the `Keyword` with the given name, if it's present in the list of
 /// `Keyword` arguments.
 pub fn find_keyword<'a>(keywords: &'a [Keyword], keyword_name: &str) -> Option<&'a Keyword> {

src/checkers/ast.rs

@@ -1588,7 +1588,7 @@ where
                     pylint::plugins::used_prior_global_declaration(self, id, expr);
                 }
             }
-            ExprKind::Attribute { attr, .. } => {
+            ExprKind::Attribute { attr, value, .. } => {
                 // Ex) typing.List[...]
                 if !self.in_deferred_string_type_definition
                     && self.settings.enabled.contains(&CheckCode::UP006)
@@ -1629,11 +1629,16 @@ where
                 ] {
                     if self.settings.enabled.contains(&code) {
                         if attr == name {
+                            // Avoid flagging on function calls (e.g., `df.values()`).
                             if let Some(parent) = self.current_expr_parent() {
                                 if matches!(parent.0.node, ExprKind::Call { .. }) {
                                     continue;
                                 }
                             }
+                            // Avoid flagging on non-DataFrames (e.g., `{"a": 1}.values`).
+                            if helpers::is_non_variable(value) {
+                                continue;
+                            }
                             self.add_check(Check::new(code.kind(), Range::from_located(expr)));
                         };
                     }

src/pandas_vet/mod.rs

@@ -81,7 +81,8 @@ mod tests {
     #[test_case("result = df.to_array()", &[]; "PD011_pass_to_array")]
     #[test_case("result = df.array", &[]; "PD011_pass_array")]
     #[test_case("result = df.values", &[CheckCode::PD011]; "PD011_fail_values")]
-    #[test_case("result = {}.values()", &[]; "PD011_pass_values_call")]
+    #[test_case("result = df.values()", &[]; "PD011_pass_values_call")]
+    #[test_case("result = {}.values", &[]; "PD011_pass_values_dict")]
     #[test_case("result = values", &[]; "PD011_pass_node_name")]
     #[test_case("employees = pd.read_csv(input_file)", &[]; "PD012_pass_read_csv")]
     #[test_case("employees = pd.read_table(input_file)", &[CheckCode::PD012]; "PD012_fail_read_table")]