fixed some info fields in MEG interpolation across sensor types using…

mne/channels/interpolation.py

@@ -484,13 +484,35 @@ def _interpolate_to_meg(inst, sensors, origin, mode):
     if len(picks_meg_good) == 0:
         raise ValueError("No good MEG channels available for interpolation.")
 
-    # Load target sensor configuration
-    info_to = read_meg_canonical_info(sensors)
-    info_to["dev_head_t"] = deepcopy(inst.info["dev_head_t"])
+    # Load target sensor configuration as info file
+    info_cano = read_meg_canonical_info(sensors)
 
     # Get source MEG info
     info_from = pick_info(inst.info, picks_meg_good)
 
+    # Design target info like source, except for channel info and
+    # some (possibly) related fields
+    info_to = deepcopy(info_from)
+    info_to._unlocked = True  # make all info fields modifiable
+    # Update channel info to the desired one
+    info_to["chs"] = deepcopy(info_cano["chs"])
+    info_to["ch_names"] = deepcopy(info_cano["ch_names"])
+    info_to["nchan"] = deepcopy(info_cano["nchan"])
+    # Reset some channel and machine-related fields to avoid confusion later on
+    info_to["device_info"] = None
+    info_to["helium_info"] = None
+    info_to["proj_id"] = None
+    info_to["proj_name"] = None
+    info_to["gantry_angle"] = None
+    # we keep original 'dev_head_t'
+    info_to["ctf_head_t"] = None
+    info_to["dev_ctf_t"] = None
+    # info_to['dig'] = None  # or should they be removed, too?
+    info_to["bads"] = []
+    info_to["projs"] = []
+    info_to["comps"] = []
+    info_to._unlocked = False  # lock info again
+
     # Compute field interpolation mapping
     origin_val = _check_origin(origin, inst.info)
     mapping = _map_meg_or_eeg_channels(info_from, info_to, mode=mode, origin=origin_val)