run_command: Fix error message on incorrect argument
Be more descriptive so people know what they can do.
@@ -1421,7 +1421,8 @@ class Interpreter(InterpreterBase):
elif isinstance(cmd, str):
cmd = [cmd]
else:
- raise InterpreterException('First argument is of incorrect type.')
+ raise InterpreterException('First argument should be find_program() '
+ 'or string, not {!r}'.format(cmd))
expanded_args = []
for a in mesonlib.flatten(cargs):
if isinstance(a, str):
