wip: .vyi files

examples/tokens/ERC721.vy

@@ -14,7 +14,7 @@ interface ERC721Receiver:
             _operator: address,
             _from: address,
             _tokenId: uint256,
-            _data: Bytes[1024]
+            _data: Bytes[...]
         ) -> bytes4: nonpayable
 
 

vyper/ast/annotation.py

@@ -164,6 +164,8 @@ def visit_Constant(self, node):
             node.ast_type = "Str"
         elif isinstance(node.value, bytes):
             node.ast_type = "Bytes"
+        elif isinstance(node.value, Ellipsis.__class__):
+            node.ast_type = "Ellipsis"
         else:
             raise SyntaxException(
                 "Invalid syntax (unsupported Python Constant AST node).",

vyper/ast/nodes.py

@@ -898,12 +898,16 @@ def validate(self):
             raise InvalidLiteral("Cannot have an empty tuple", self)
 
 
-class Dict(ExprNode):
-    __slots__ = ("keys", "values")
+class NameConstant(Constant):
+    __slots__ = ()
 
 
-class NameConstant(Constant):
-    __slots__ = ("value",)
+class Ellipsis(Constant):
+    __slots__ = ()
+
+
+class Dict(ExprNode):
+    __slots__ = ("keys", "values")
 
 
 class Name(ExprNode):

vyper/ast/nodes.pyi

@@ -121,6 +121,10 @@ class Bytes(Constant):
     @property
     def s(self): ...
 
+class NameConstant(Constant): ...
+
+class Ellipsis(Constant): ...
+
 class List(VyperNode):
     elements: list = ...
 
@@ -131,8 +135,6 @@ class Dict(VyperNode):
     keys: list = ...
     values: list = ...
 
-class NameConstant(Constant): ...
-
 class Name(VyperNode):
     id: str = ...
     _type: str = ...

vyper/semantics/analysis/module.py

@@ -378,12 +378,22 @@ def _load_import(self, node: vy_ast.VyperNode, level: int, module_str: str, alia
         except FileNotFoundError:
             pass
 
+        try:
+            file = self.input_bundle.load_file(path.with_suffix(".vyi"))
+            assert isinstance(file, FileInput)  # mypy hint
+            interface_ast = vy_ast.parse_to_ast(file.source_code, contract_name=str(file.path))
+            return InterfaceT.from_vyi(interface_ast)
+        except FileNotFoundError:
+            pass
+
         try:
             file = self.input_bundle.load_file(path.with_suffix(".json"))
             assert isinstance(file, ABIInput)  # mypy hint
             return InterfaceT.from_json_abi(str(file.path), file.abi)
         except FileNotFoundError:
-            raise ModuleNotFoundError(module_str)
+            pass
+
+        raise ModuleNotFoundError(module_str)
 
 
 # convert an import to a path (without suffix)
@@ -425,7 +435,7 @@ def _load_builtin_import(level: int, module_str: str) -> InterfaceT:
         remapped_module = remapped_module.removeprefix("vyper.interfaces")
         remapped_module = vyper.builtins.interfaces.__package__ + remapped_module
 
-    path = _import_to_path(level, remapped_module).with_suffix(".vy")
+    path = _import_to_path(level, remapped_module).with_suffix(".vyi")
 
     try:
         file = input_bundle.load_file(path)
@@ -435,4 +445,4 @@ def _load_builtin_import(level: int, module_str: str) -> InterfaceT:
 
     # TODO: it might be good to cache this computation
     interface_ast = vy_ast.parse_to_ast(file.source_code, module_path=path)
-    return InterfaceT.from_Module(interface_ast, name=module_str)
+    return InterfaceT.from_vyi(interface_ast)