Raising meaningful warnings/errors for interpolate_bads, when supplie…

mne/channels/channels.py

@@ -828,6 +828,7 @@ def interpolate_bads(
         method=None,
         exclude=(),
         verbose=None,
+        **kwargs,
     ):
         """Interpolate bad MEG and EEG channels.
 
@@ -896,6 +897,28 @@ def interpolate_bads(
 
         _check_preload(self, "interpolation")
         _validate_type(method, (dict, str, None), "method")
+        bads_to_check = self.info["bads"]
+        for ch_name in bads_to_check:
+            try:
+                ch_idx = self.ch_names.index(ch_name)
+                ch_loc = self.info["chs"][ch_idx]["loc"]
+                is_loc_invalid = np.allclose(ch_loc, 0.0, atol=1e-16) or np.any(
+                    np.isnan(ch_loc)
+                )
+            except ValueError:
+                continue
+
+            if is_loc_invalid:
+                msg = (
+                    f"Bad channel '{ch_name}' is missing valid sensor position (loc) information. "
+                    "Interpolation cannot proceed correctly."
+                )
+                _on_missing(
+                    kwargs.get("on_no_position", "error"),
+                    msg + " If you want to continue despite missing positions, set "
+                    "on_no_position='warn' or 'ignore'.",
+                )
+
         method = _handle_default("interpolation_method", method)
         ch_types = self.get_channel_types(unique=True)
         # figure out if we have "mag" for "meg", "hbo" for "fnirs", ... to filter the