feat[lang]: add module.__at__() to cast to interface

tests/functional/codegen/modules/test_exports.py

@@ -440,3 +440,26 @@ def __init__():
     # call `c.__default__()`
     env.message_call(c.address)
     assert c.counter() == 6
+
+
+def test_inline_interface_export(make_input_bundle, get_contract):
+    lib1 = """
+interface IAsset:
+    def asset() -> address: view
+
+implements: IAsset
+
+@external
+@view
+def asset() -> address:
+    return self
+    """
+    main = """
+import lib1
+
+exports: lib1.IAsset
+    """
+    input_bundle = make_input_bundle({"lib1.vy": lib1})
+    c = get_contract(main, input_bundle=input_bundle)
+
+    assert c.asset() == c.address

tests/functional/codegen/modules/test_interface_imports.py

@@ -50,11 +50,40 @@ def foo() -> bool:
     # check that this typechecks both directions
     a: lib1.IERC20 = IERC20(msg.sender)
     b: lib2.IERC20 = IERC20(msg.sender)
+    c: IERC20 = lib1.IERC20(msg.sender)  # allowed in call position
 
     # return the equality so we can sanity check it
-    return a == b
+    return a == b and b == c
     """
     input_bundle = make_input_bundle({"lib1.vy": lib1, "lib2.vy": lib2})
     c = get_contract(main, input_bundle=input_bundle)
 
     assert c.foo() is True
+
+
+def test_intrinsic_interface(get_contract, make_input_bundle):
+    lib = """
+@external
+@view
+def foo() -> uint256:
+    # detect self call
+    if msg.sender == self:
+        return 4
+    else:
+        return 5
+    """
+    main = """
+import lib
+
+exports: lib.__interface__
+
+@external
+@view
+def bar() -> uint256:
+    return staticcall lib.__interface__(self).foo()
+    """
+    input_bundle = make_input_bundle({"lib.vy": lib})
+    c = get_contract(main, input_bundle=input_bundle)
+
+    assert c.foo() == 5
+    assert c.bar() == 4

tests/functional/syntax/modules/test_exports.py

@@ -385,6 +385,28 @@ def do_xyz():
     assert e.value._message == "requested `lib1.ifoo` but `lib1` does not implement `lib1.ifoo`!"
 
 
+def test_no_export_unimplemented_inline_interface(make_input_bundle):
+    lib1 = """
+interface ifoo:
+    def do_xyz(): nonpayable
+
+# technically implements ifoo, but missing `implements: ifoo`
+
+@external
+def do_xyz():
+    pass
+    """
+    main = """
+import lib1
+
+exports: lib1.ifoo
+    """
+    input_bundle = make_input_bundle({"lib1.vy": lib1})
+    with pytest.raises(InterfaceViolation) as e:
+        compile_code(main, input_bundle=input_bundle)
+    assert e.value._message == "requested `lib1.ifoo` but `lib1` does not implement `lib1.ifoo`!"
+
+
 def test_export_selector_conflict(make_input_bundle):
     ifoo = """
 @external

vyper/semantics/analysis/module.py

@@ -54,7 +54,7 @@
 )
 from vyper.semantics.data_locations import DataLocation
 from vyper.semantics.namespace import Namespace, get_namespace, override_global_namespace
-from vyper.semantics.types import EventT, FlagT, InterfaceT, StructT
+from vyper.semantics.types import EventT, FlagT, InterfaceT, StructT, is_type_t
 from vyper.semantics.types.function import ContractFunctionT
 from vyper.semantics.types.module import ModuleT
 from vyper.semantics.types.utils import type_from_annotation
@@ -547,7 +547,9 @@ def visit_ExportsDecl(self, node):
             elif isinstance(info.typ, ContractFunctionT):
                 # regular function
                 funcs = [info.typ]
-            elif isinstance(info.typ, InterfaceT):
+            elif is_type_t(info.typ, InterfaceT):
+                interface_t = info.typ.typedef
+
                 if not isinstance(item, vy_ast.Attribute):
                     raise StructureException(
                         "invalid export",
@@ -558,7 +560,7 @@ def visit_ExportsDecl(self, node):
                 if module_info is None:
                     raise StructureException("not a valid module!", item.value)
 
-                if info.typ not in module_info.typ.implemented_interfaces:
+                if interface_t not in module_info.typ.implemented_interfaces:
                     iface_str = item.node_source_code
                     module_str = item.value.node_source_code
                     msg = f"requested `{iface_str}` but `{module_str}`"
@@ -569,7 +571,7 @@ def visit_ExportsDecl(self, node):
                 # find the specific implementation of the function in the module
                 funcs = [
                     module_exposed_fns[fn.name]
-                    for fn in info.typ.functions.values()
+                    for fn in interface_t.functions.values()
                     if fn.is_external
                 ]
             else:

vyper/semantics/analysis/utils.py

@@ -197,7 +197,7 @@ def _raise_invalid_reference(name, node):
         try:
             s = t.get_member(name, node)
 
-            if isinstance(s, (VyperType, TYPE_T)):
+            if isinstance(s, VyperType):
                 # ex. foo.bar(). bar() is a ContractFunctionT
                 return [s]
 

vyper/semantics/types/module.py

@@ -323,16 +323,23 @@ def __init__(self, module: vy_ast.Module, name: Optional[str] = None):
 
         for i in self.import_stmts:
             import_info = i._metadata["import_info"]
-            self.add_member(import_info.alias, import_info.typ)
 
             if hasattr(import_info.typ, "module_t"):
-                self._helper.add_member(import_info.alias, TYPE_T(import_info.typ))
+                module_info = import_info.typ
+                # get_expr_info uses ModuleInfo
+                self.add_member(import_info.alias, module_info)
+                # type_from_annotation uses TYPE_T
+                self._helper.add_member(import_info.alias, TYPE_T(module_info.module_t))
+            else:  # interfaces
+                self.add_member(import_info.alias, TYPE_T(import_info.typ))
 
         for name, interface_t in self.interfaces.items():
             # can access interfaces in type position
             self._helper.add_member(name, TYPE_T(interface_t))
 
-        self.add_member("__interface__", self.interface)
+        # can use module.__interface__ in call position
+        self.add_member("__interface__", TYPE_T(self.interface))
+        self._helper.add_member("__interface__", TYPE_T(self.interface))
 
     # __eq__ is very strict on ModuleT - object equality! this is because we
     # don't want to reason about where a module came from (i.e. input bundle,