[DatePicker] Remove dead dom node

[damir-sirola]

Unable to modify styling on MuiPickersDay because the Typography styling overrides it

Environment

Tech	Version
@material-ui/pickers	3.2.4
material-ui	4.3.3
React	16.9.0
Browser	N/A
Peer library	N/A

Steps to reproduce

1. Modify theme by setting some styling overrides for Typography body2
2. Modify theme by setting some styling overrides for MuiPickersDay

For example

const overrides = {
    MuiTypography: {
        body2: {
            fontWeight: 300
        }
    }
    MuiPickerDay: {
        day: {
            fontWeight: 500
        }
    }
}

Expected behavior

I expect styling defined in MuiPickersDay override to be applied

Actual behavior

Styles specified in Typography are applied because they're stronger than MuiPickersDay.day

Live example

[oliviertassinari]

@damir-sirola Do you have a reproduction? I can't observe the issue. We can't help without.

[oliviertassinari]

It seems that we can lighten the rendering of the day component:

diff --git a/packages/material-ui-lab/src/PickersDay/PickersDay.tsx b/packages/material-ui-lab/src/PickersDay/PickersDay.tsx
index e74ef05239..271e2563e8 100644
--- a/packages/material-ui-lab/src/PickersDay/PickersDay.tsx
+++ b/packages/material-ui-lab/src/PickersDay/PickersDay.tsx
@@ -62,9 +62,6 @@ export const styles = (theme: Theme) =>
         border: `1px solid ${theme.palette.text.secondary}`,
       },
     },
-    dayLabel: {
-      // need for overrides
-    },
     selected: {},
     disabled: {},
   });
@@ -236,7 +233,7 @@ const PickersDay = React.forwardRef(function PickersDay<TDate>(
       onClick={handleClick}
       {...other}
     >
-      <span className={classes.dayLabel}>{utils.format(day, 'dayOfMonth')}</span>
+      {utils.format(day, 'dayOfMonth')}
     </ButtonBase>
   );
 });

It will also help with mui/mui-x#4602.

Does anyone want to work on it? :)

[mxsph]

I've started to work on this issue :)