`Case` coercion of Structs loses field names

[alamb]

Describe the bug

Found while working on

• Type Coercion fails for List with inner type struct which has large/view types #14154 it may be the same

When two structs are coerced as part of case, the field names are lost (set to c0)

To Reproduce

create table t as values
(
 100,                                      -- column1 int (so the case isn't constant folded)
 { 'foo': 'bar' },                         -- column2 has List of Struct w/ Utf8
 { 'foo': arrow_cast('baz', 'Utf8View') }  -- column3 has List of Struct w/ Utf8View
);

 -- fields are correctly names 'foo'
SELECT column2, column3  FROM t;

-- +------------+------------+
-- | column2    | column3    |
-- +------------+------------+
-- | {foo: bar} | {foo: baz} |
-- +------------+------------+
-- 1 row(s) fetched.

-- When coerced the field name turns into `c0` should be `foo`
SELECT case when column1 > 0 then column2 else column3 end FROM t;

-- +------------------------------------------------------------------+
-- | CASE WHEN t.column1 > Int64(0) THEN t.column2 ELSE t.column3 END |
-- +------------------------------------------------------------------+
-- | {c0: bar}                                                        |
-- +------------------------------------------------------------------+

Expected behavior

The results should be

{foo: bar}

Additional context

No response

[alamb]

Actually I tested this in DataFuson 43 and it also fails

[ion-elgreco]

I have actually seen this, but thought it was a visual bug 😮

[alamb]

We'll get it fixed

[alamb]

• Do not rename struct fields when coercing types in CASE #14384