fix: allow using interface defs from imported modules (vyperlang#3725)

- add interface defs to ModuleT's exposed `get_type_members()`
- slight refactor of ModuleT to have a special helper instead of
dispatching to `self.interface`

tests/functional/codegen/modules/test_interface_imports.py

@@ -0,0 +1,31 @@
+def test_import_interface_types(make_input_bundle, get_contract):
+    ifaces = """
+interface IFoo:
+    def foo() -> uint256: nonpayable
+    """
+
+    foo_impl = """
+import ifaces
+
+implements: ifaces.IFoo
+
+@external
+def foo() -> uint256:
+    return block.number
+    """
+
+    contract = """
+import ifaces
+
+@external
+def test_foo(s: ifaces.IFoo) -> bool:
+    assert s.foo() == block.number
+    return True
+    """
+
+    input_bundle = make_input_bundle({"ifaces.vy": ifaces})
+
+    foo = get_contract(foo_impl, input_bundle=input_bundle)
+    c = get_contract(contract, input_bundle=input_bundle)
+
+    assert c.test_foo(foo.address) is True

tests/functional/syntax/test_interfaces.py

@@ -90,7 +90,7 @@ def foo(): nonpayable
         """
 implements: self.x
     """,
-        StructureException,
+        InvalidType,
     ),
     (
         """

vyper/ast/nodes.py

@@ -1372,8 +1372,8 @@ class ImplementsDecl(Stmt):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
-        if not isinstance(self.annotation, Name):
-            raise StructureException("not an identifier", self.annotation)
+        if not isinstance(self.annotation, (Name, Attribute)):
+            raise StructureException("invalid implements", self.annotation)
 
 
 class If(Stmt):

vyper/semantics/analysis/module.py

@@ -383,8 +383,9 @@ def visit_ImportFrom(self, node):
         self._add_import(node, node.level, qualified_module_name, alias)
 
     def visit_InterfaceDef(self, node):
-        obj = InterfaceT.from_InterfaceDef(node)
-        self.namespace[node.name] = obj
+        interface_t = InterfaceT.from_InterfaceDef(node)
+        node._metadata["interface_type"] = interface_t
+        self.namespace[node.name] = interface_t
 
     def visit_StructDef(self, node):
         struct_t = StructT.from_StructDef(node)

vyper/semantics/types/module.py

@@ -39,6 +39,7 @@ def __init__(self, _id: str, functions: dict, events: dict, structs: dict) -> No
 
         self._helper = VyperType(events | structs)
         self._id = _id
+        self._helper._id = _id
         self.functions = functions
         self.events = events
         self.structs = structs
@@ -267,6 +268,8 @@ def from_InterfaceDef(cls, node: vy_ast.InterfaceDef) -> "InterfaceT":
 
 # Datatype to store all module information.
 class ModuleT(VyperType):
+    _attribute_in_annotation = True
+
     def __init__(self, module: vy_ast.Module, name: Optional[str] = None):
         super().__init__()
 
@@ -276,7 +279,10 @@ def __init__(self, module: vy_ast.Module, name: Optional[str] = None):
 
         # compute the interface, note this has the side effect of checking
         # for function collisions
-        self._helper = self.interface
+        _ = self.interface
+
+        self._helper = VyperType()
+        self._helper._id = self._id
 
         for f in self.function_defs:
             # note: this checks for collisions
@@ -289,6 +295,12 @@ def __init__(self, module: vy_ast.Module, name: Optional[str] = None):
         for s in self.struct_defs:
             # add the type of the struct so it can be used in call position
             self.add_member(s.name, TYPE_T(s._metadata["struct_type"]))  # type: ignore
+            self._helper.add_member(s.name, TYPE_T(s._metadata["struct_type"]))  # type: ignore
+
+        for i in self.interface_defs:
+            # add the type of the interface so it can be used in call position
+            self.add_member(i.name, TYPE_T(i._metadata["interface_type"]))  # type: ignore
+            self._helper.add_member(i.name, TYPE_T(i._metadata["interface_type"]))  # type: ignore
 
         for v in self.variable_decls:
             self.add_member(v.target.id, v.target._metadata["varinfo"])
@@ -322,6 +334,10 @@ def event_defs(self):
     def struct_defs(self):
         return self._module.get_children(vy_ast.StructDef)
 
+    @property
+    def interface_defs(self):
+        return self._module.get_children(vy_ast.InterfaceDef)
+
     @property
     def import_stmts(self):
         return self._module.get_children((vy_ast.Import, vy_ast.ImportFrom))

vyper/semantics/types/utils.py

@@ -127,14 +127,16 @@ def _type_from_annotation(node: vy_ast.VyperNode) -> VyperType:
         except UndeclaredDefinition:
             raise InvalidType(err_msg, node) from None
 
-        interface = module_or_interface
         if hasattr(module_or_interface, "module_t"):  # i.e., it's a ModuleInfo
-            interface = module_or_interface.module_t.interface
+            module_or_interface = module_or_interface.module_t
 
-        if not interface._attribute_in_annotation:
+        if not isinstance(module_or_interface, VyperType):
             raise InvalidType(err_msg, node)
 
-        type_t = interface.get_type_member(node.attr, node)
+        if not module_or_interface._attribute_in_annotation:
+            raise InvalidType(err_msg, node)
+
+        type_t = module_or_interface.get_type_member(node.attr, node)  # type: ignore
         assert isinstance(type_t, TYPE_T)  # sanity check
         return type_t.typedef