id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
1174907042,PR_kwDOAMm_X840t0YV,6390,[skip-ci] Add benchmarks for groupby math,2448579,closed,0,,,0,2022-03-21T05:25:25Z,2022-03-21T07:51:18Z,2022-03-21T07:51:16Z,MEMBER,,0,pydata/xarray/pulls/6390,From #6160,"{""url"": ""https://api.github.com/repos/pydata/xarray/issues/6390/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,pull
1174177534,I_kwDOAMm_X85F_Ib-,6381,vectorized indexing with DataArray should not preserve IndexVariable,2448579,closed,0,,,1,2022-03-19T05:08:39Z,2022-03-21T04:47:47Z,2022-03-21T04:47:47Z,MEMBER,,,,"### What happened?

After vectorized indexing a DataArray with dim `x`by a DataArray `z`, we get a DataArray with dim `z` and `x` as non-dim coordinate. But `x`  is still an IndexVariable, not a normal variable.

### What did you expect to happen?

`x` should be a normal variable.

### Minimal Complete Verifiable Example

```python
import xarray as xr
xr.set_options(display_style=""text"")

da = xr.DataArray([1, 2, 3], dims=""x"", coords={""x"": [0, 1, 2]})
idxr = xr.DataArray([1], dims=""z"", name=""x"", coords={""z"": (""z"", [""a""])})
da.sel(x=idxr)
```

```
<xarray.DataArray (z: 1)>
array([2])
Coordinates:
    x        (z) int64 1
  * z        (z) <U1 'a'
```

`x` is a non-dim coordinate but is backed by a IndexVariable with the wrong name!
```python
da.sel(x=idxr).x.variable
```

```
<xarray.IndexVariable 'z' (z: 1)>
array([1])
```

### Relevant log output

_No response_

### Anything else we need to know?

_No response_

### Environment

xarray main but this bug was present prior to the explicit indexes refactor.","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/6381/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue