Enable attribute lookups via semantic model

crates/ruff/resources/test/fixtures/flake8_raise/RSE102.py

@@ -29,6 +29,26 @@
     # Hello, world!
 )
 
+# OK
 raise AssertionError
 
+# OK
 raise AttributeError("test message")
+
+
+def return_error():
+    return ValueError("Something")
+
+
+# OK
+raise return_error()
+
+
+class Class:
+    @staticmethod
+    def error():
+        return ValueError("Something")
+
+
+# OK
+raise Class.error()

crates/ruff/src/checkers/ast/mod.rs

@@ -1778,15 +1778,13 @@ where
         match stmt {
             Stmt::FunctionDef(ast::StmtFunctionDef {
                 body,
-                name,
                 args,
                 decorator_list,
                 returns,
                 ..
             })
             | Stmt::AsyncFunctionDef(ast::StmtAsyncFunctionDef {
                 body,
-                name,
                 args,
                 decorator_list,
                 returns,
@@ -1845,13 +1843,6 @@ where
                     };
                 }
 
-                self.add_binding(
-                    name,
-                    stmt.identifier(),
-                    BindingKind::FunctionDefinition,
-                    BindingFlags::empty(),
-                );
-
                 let definition = docstrings::extraction::extract_definition(
                     ExtractionTarget::Function,
                     stmt,
@@ -2061,19 +2052,28 @@ where
 
         // Post-visit.
         match stmt {
-            Stmt::FunctionDef(_) | Stmt::AsyncFunctionDef(_) => {
-                self.deferred.scopes.push(self.semantic.scope_id);
+            Stmt::FunctionDef(ast::StmtFunctionDef { name, .. })
+            | Stmt::AsyncFunctionDef(ast::StmtAsyncFunctionDef { name, .. }) => {
+                let scope_id = self.semantic.scope_id;
+                self.deferred.scopes.push(scope_id);
                 self.semantic.pop_scope();
                 self.semantic.pop_definition();
+                self.add_binding(
+                    name,
+                    stmt.identifier(),
+                    BindingKind::FunctionDefinition(scope_id),
+                    BindingFlags::empty(),
+                );
             }
             Stmt::ClassDef(ast::StmtClassDef { name, .. }) => {
-                self.deferred.scopes.push(self.semantic.scope_id);
+                let scope_id = self.semantic.scope_id;
+                self.deferred.scopes.push(scope_id);
                 self.semantic.pop_scope();
                 self.semantic.pop_definition();
                 self.add_binding(
                     name,
                     stmt.identifier(),
-                    BindingKind::ClassDefinition,
+                    BindingKind::ClassDefinition(scope_id),
                     BindingFlags::empty(),
                 );
             }
@@ -3884,7 +3884,7 @@ where
                         }
 
                         // Store the existing binding, if any.
-                        let existing_id = self.semantic.lookup(name);
+                        let existing_id = self.semantic.lookup_symbol(name);
 
                         // Add the bound exception name to the scope.
                         let binding_id = self.add_binding(

crates/ruff/src/renamer.rs

@@ -248,8 +248,8 @@ impl Renamer {
             | BindingKind::LoopVar
             | BindingKind::Global
             | BindingKind::Nonlocal(_)
-            | BindingKind::ClassDefinition
-            | BindingKind::FunctionDefinition
+            | BindingKind::ClassDefinition(_)
+            | BindingKind::FunctionDefinition(_)
             | BindingKind::Deletion
             | BindingKind::UnboundException(_) => {
                 Some(Edit::range_replacement(target.to_string(), binding.range))

crates/ruff/src/rules/flake8_raise/rules/unnecessary_paren_on_raise_exception.rs

@@ -2,6 +2,7 @@ use rustpython_parser::ast::{self, Expr, Ranged};
 
 use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
+
 use ruff_python_ast::helpers::match_parens;
 
 use crate::checkers::ast::Checker;
@@ -53,6 +54,17 @@ pub(crate) fn unnecessary_paren_on_raise_exception(checker: &mut Checker, expr:
     }) = expr
     {
         if args.is_empty() && keywords.is_empty() {
+            // `raise func()` still requires parentheses; only `raise Class()` does not.
+            if checker
+                .semantic()
+                .lookup_attribute(func)
+                .map_or(false, |id| {
+                    checker.semantic().binding(id).kind.is_function_definition()
+                })
+            {
+                return;
+            }
+
             let range = match_parens(func.end(), checker.locator)
                 .expect("Expected call to include parentheses");
             let mut diagnostic = Diagnostic::new(UnnecessaryParenOnRaiseException, range);

crates/ruff/src/rules/flake8_raise/snapshots/ruff__rules__flake8_raise__tests__unnecessary-paren-on-raise-exception_RSE102.py.snap

@@ -118,7 +118,7 @@ RSE102.py:28:16: RSE102 [*] Unnecessary parentheses on raised exception
 30 | | )
    | |_^ RSE102
 31 |   
-32 |   raise AssertionError
+32 |   # OK
    |
    = help: Remove unnecessary parentheses
 
@@ -131,7 +131,7 @@ RSE102.py:28:16: RSE102 [*] Unnecessary parentheses on raised exception
 30    |-)
    28 |+raise TypeError
 31 29 | 
-32 30 | raise AssertionError
-33 31 | 
+32 30 | # OK
+33 31 | raise AssertionError
 
 

crates/ruff_python_semantic/src/binding.rs

@@ -126,11 +126,11 @@ impl<'a> Binding<'a> {
         }
         matches!(
             existing.kind,
-            BindingKind::ClassDefinition
-                | BindingKind::FunctionDefinition
-                | BindingKind::Import(..)
-                | BindingKind::FromImport(..)
-                | BindingKind::SubmoduleImport(..)
+            BindingKind::ClassDefinition(_)
+                | BindingKind::FunctionDefinition(_)
+                | BindingKind::Import(_)
+                | BindingKind::FromImport(_)
+                | BindingKind::SubmoduleImport(_)
         )
     }
 
@@ -372,14 +372,14 @@ pub enum BindingKind<'a> {
     /// class Foo:
     ///     ...
     /// ```
-    ClassDefinition,
+    ClassDefinition(ScopeId),
 
     /// A binding for a function, like `foo` in:
     /// ```python
     /// def foo():
     ///     ...
     /// ```
-    FunctionDefinition,
+    FunctionDefinition(ScopeId),
 
     /// A binding for an `__all__` export, like `__all__` in:
     /// ```python

crates/ruff_python_semantic/src/model.rs

@@ -414,7 +414,7 @@ impl<'a> SemanticModel<'a> {
 
     /// Lookup a symbol in the current scope. This is a carbon copy of [`Self::resolve_read`], but
     /// doesn't add any read references to the resolved symbol.
-    pub fn lookup(&mut self, symbol: &str) -> Option<BindingId> {
+    pub fn lookup_symbol(&self, symbol: &str) -> Option<BindingId> {
         if self.in_forward_reference() {
             if let Some(binding_id) = self.scopes.global().get(symbol) {
                 if !self.bindings[binding_id].is_unbound() {
@@ -456,6 +456,32 @@ impl<'a> SemanticModel<'a> {
         None
     }
 
+    /// Lookup a qualified attribute in the current scope.
+    ///
+    /// For example, given `["Class", "method"`], resolve the `BindingKind::ClassDefinition`
+    /// associated with `Class`, then the `BindingKind::FunctionDefinition` associated with
+    /// `Class#method`.
+    pub fn lookup_attribute(&'a self, value: &'a Expr) -> Option<BindingId> {
+        let call_path = collect_call_path(value)?;
+
+        // Find the symbol in the current scope.
+        let (symbol, attribute) = call_path.split_first()?;
+        let mut binding_id = self.lookup_symbol(symbol)?;
+
+        // Recursively resolve class attributes, e.g., `foo.bar.baz` in.
+        let mut tail = attribute;
+        while let Some((symbol, rest)) = tail.split_first() {
+            // Find the next symbol in the class scope.
+            let BindingKind::ClassDefinition(scope_id) = self.binding(binding_id).kind else {
+                return None;
+            };
+            binding_id = self.scopes[scope_id].get(symbol)?;
+            tail = rest;
+        }
+
+        Some(binding_id)
+    }
+
     /// Given a `BindingId`, return the `BindingId` of the submodule import that it aliases.
     fn resolve_submodule(
         &self,