[red-knot] Resolve function annotations before adding function symbol (#13084)

This PR has the `SemanticIndexBuilder` visit function definition
annotations before adding the function symbol/name to the builder.

For example, the following snippet no longer causes a panic:

```python
def bool(x) -> bool:
    Return True
```

Note: This fix changes the ordering of the global symbol table.

Closes #13069

crates/red_knot_python_semantic/src/semantic_index.rs

@@ -575,7 +575,7 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):
         let index = semantic_index(&db, file);
         let global_table = symbol_table(&db, global_scope(&db, file));
 
-        assert_eq!(names(&global_table), vec!["f", "str", "int"]);
+        assert_eq!(names(&global_table), vec!["str", "int", "f"]);
 
         let [(function_scope_id, _function_scope)] = index
             .child_scopes(FileScopeId::global())

crates/red_knot_python_semantic/src/semantic_index/builder.rs

@@ -392,20 +392,6 @@ where
                     self.visit_decorator(decorator);
                 }
 
-                let symbol = self
-                    .add_or_update_symbol(function_def.name.id.clone(), SymbolFlags::IS_DEFINED);
-                self.add_definition(symbol, function_def);
-
-                // The default value of the parameters needs to be evaluated in the
-                // enclosing scope.
-                for default in function_def
-                    .parameters
-                    .iter_non_variadic_params()
-                    .filter_map(|param| param.default.as_deref())
-                {
-                    self.visit_expr(default);
-                }
-
                 self.with_type_params(
                     NodeWithScopeRef::FunctionTypeParameters(function_def),
                     function_def.type_params.as_deref(),
@@ -426,6 +412,21 @@ where
                         builder.pop_scope()
                     },
                 );
+                // The default value of the parameters needs to be evaluated in the
+                // enclosing scope.
+                for default in function_def
+                    .parameters
+                    .iter_non_variadic_params()
+                    .filter_map(|param| param.default.as_deref())
+                {
+                    self.visit_expr(default);
+                }
+                // The symbol for the function name itself has to be evaluated
+                // at the end to match the runtime evaluation of parameter defaults
+                // and return-type annotations.
+                let symbol = self
+                    .add_or_update_symbol(function_def.name.id.clone(), SymbolFlags::IS_DEFINED);
+                self.add_definition(symbol, function_def);
             }
             ast::Stmt::ClassDef(class) => {
                 for decorator in &class.decorator_list {

crates/red_knot_python_semantic/src/types/infer.rs

@@ -374,9 +374,9 @@ impl<'db> TypeInferenceBuilder<'db> {
         let Some(type_params) = function.type_params.as_deref() else {
             panic!("function type params scope without type params");
         };
+        self.infer_optional_expression(function.returns.as_deref());
         self.infer_type_parameters(type_params);
         self.infer_parameters(&function.parameters);
-        self.infer_optional_expression(function.returns.as_deref());
     }
 
     fn infer_function_body(&mut self, function: &ast::StmtFunctionDef) {

crates/red_knot_workspace/resources/test/corpus/25_func_annotations_same_name.py

@@ -0,0 +1,11 @@
+def bool(x) -> bool:
+    return True
+
+
+class MyClass: ...
+
+
+def MyClass() -> MyClass: ...
+
+
+def x(self) -> x: ...

crates/red_knot_workspace/resources/test/corpus/26_func_defaults_same_name.py

@@ -0,0 +1,2 @@
+def bool(x=bool):
+    return x