interpreter: move KwargInfo('depends') to type_checking

mesonbuild/interpreter/interpreter.py

@@ -50,6 +50,7 @@ from .interpreterobjects import (
     NullSubprojectInterpreter,
 )
 from .type_checking import (
+    DEPENDS_KW,
     DEPFILE_KW,
     ENV_KW,
     INSTALL_MODE_KW,
@@ -1676,12 +1677,7 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
             listify=True,
             default=[],
         ),
-        KwargInfo(
-            'depends',
-            ContainerTypeInfo(list, (build.BuildTarget, build.CustomTarget)),
-            listify=True,
-            default=[],
-        ),
+        DEPENDS_KW,
         ENV_KW.evolve(since='0.57.0'),
     )
     def func_run_target(self, node: mparser.FunctionNode, args: T.Tuple[str],

mesonbuild/interpreter/type_checking.py

@@ -6,7 +6,7 @@
 import typing as T
 
 from .. import compilers
-from ..build import EnvironmentVariables
+from ..build import EnvironmentVariables, CustomTarget, BuildTarget
 from ..coredata import UserFeatureOption
 from ..interpreterbase import TYPE_var
 from ..interpreterbase.decorators import KwargInfo, ContainerTypeInfo
@@ -183,3 +183,10 @@ DEPFILE_KW: KwargInfo[T.Optional[str]] = KwargInfo(
     (str, type(None)),
     validator=lambda x: 'Depfile must be a plain filename with a subdirectory' if has_path_sep(x) else None
 )
+
+DEPENDS_KW: KwargInfo[T.List[T.Union[BuildTarget, CustomTarget]]] = KwargInfo(
+    'depends',
+    ContainerTypeInfo(list, (BuildTarget, CustomTarget)),
+    listify=True,
+    default=[],
+)