Parse type parameters in function definitions (RustPython#96)

* Parse type parameters in function definitions
* Add test for combined items

Author: zanieb

parser/src/parser.rs

@@ -663,6 +663,33 @@ class Foo[X, Y: str, *U, **P]():
 ";
         insta::assert_debug_snapshot!(ast::Suite::parse(source, "<test>").unwrap());
     }
+    #[test]
+    #[cfg(feature = "all-nodes-with-ranges")]
+    fn test_parse_function_definition() {
+        let source = "\
+def func(a):
+    ...
+
+def func[T](a: T) -> T:
+    ...
+
+def func[T: str](a: T) -> T:
+    ...
+
+def func[T: (str, bytes)](a: T) -> T:
+    ...
+
+def func[*Ts](*a: *Ts):
+    ...
+
+def func[**P](*args: P.args, **kwargs: P.kwargs):
+    ...
+
+def func[T, U: str, *Ts, **P]():
+    pass
+  ";
+        insta::assert_debug_snapshot!(ast::Suite::parse(source, "<test>").unwrap());
+    }
 
     #[test]
     fn test_parse_dict_comprehension() {

parser/src/python.lalrpop

@@ -965,16 +965,15 @@ WithItem<Goal>: ast::WithItem = {
 };
 
 FuncDef: ast::Stmt = {
-    <location:@L> <decorator_list:Decorator*> <is_async:"async"?> "def" <name:Identifier> <args:Parameters> <r:("->" <Test<"all">>)?> ":" <body:Suite> => {
+    <decorator_list:Decorator*> <location:@L> <is_async:"async"?> "def" <name:Identifier> <type_params:TypeParamList?> <args:Parameters> <r:("->" <Test<"all">>)?> ":" <body:Suite> => {
         let args = Box::new(args);
         let returns = r.map(|x| Box::new(x));
         let end_location = body.last().unwrap().end();
         let type_comment = None;
-        let type_params = Vec::new();
         if is_async.is_some() {
-            ast::StmtAsyncFunctionDef { name, args, body, decorator_list, returns, type_comment, type_params, range: (location..end_location).into() }.into()
+            ast::StmtAsyncFunctionDef { name, args, body, decorator_list, returns, type_comment, type_params: type_params.unwrap_or_default(), range: (location..end_location).into() }.into()
         } else {
-            ast::StmtFunctionDef { name, args, body, decorator_list, returns, type_comment, type_params, range: (location..end_location).into() }.into()
+            ast::StmtFunctionDef { name, args, body, decorator_list, returns, type_comment, type_params: type_params.unwrap_or_default(), range: (location..end_location).into() }.into()
         }
     },
 };