gh-104050: Add more type hints to Argument Clinic DSLParser()

Tools/clinic/clinic.py

@@ -4526,7 +4526,7 @@ def state_dsl_start(self, line: str | None) -> None:
 
         self.next(self.state_modulename_name, line)
 
-    def state_modulename_name(self, line):
+    def state_modulename_name(self, line: str | None) -> None:
         # looking for declaration, which establishes the leftmost column
         # line should be
         #     modulename.fnname [as c_basename] [-> return annotation]
@@ -4543,7 +4543,7 @@ def state_modulename_name(self, line):
         # this line is permitted to start with whitespace.
         # we'll call this number of spaces F (for "function").
 
-        if not line.strip():
+        if not self.valid_line(line):
             return
 
         self.indent.infer(line)
@@ -4588,9 +4588,9 @@ def state_modulename_name(self, line):
 
         line, _, returns = line.partition('->')
 
-        full_name, _, c_basename = line.partition(' as ')
-        full_name = full_name.strip()
-        c_basename = c_basename.strip() or None
+        left, _, right = line.partition(' as ')
+        full_name = left.strip()
+        c_basename = right.strip() or None
 
         if not is_legal_py_identifier(full_name):
             fail("Illegal function name:", full_name)
@@ -5021,7 +5021,7 @@ def bad_node(self, node):
         key = f"{parameter_name}_as_{c_name}" if c_name else parameter_name
         self.function.parameters[key] = p
 
-    KwargDict = dict[str | None, Any]
+    KwargDict = dict[str, Any]
 
     @staticmethod
     def parse_converter(annotation: ast.expr | None) -> tuple[str, bool, KwargDict]:
@@ -5031,6 +5031,7 @@ def parse_converter(annotation: ast.expr | None) -> tuple[str, bool, KwargDict]:
             case ast.Name(name):
                 return name, False, {}
             case ast.Call(func=ast.Name(name)):
+                assert isinstance(ast.expr, str)
                 symbols = globals()
                 kwargs = {
                     node.arg: eval_ast_expr(node.value, symbols)