Varchar length not honored when casting from json

[kgpai]

Expected Behavior

It seems Presto doesnt honor the length specified when casting json to varchar ; Might be true for other casts too, but I havent verified.

SELECT CAST(json_parse(x) as varchar(1)) from (values '"abcedef"') t(x)

-- output: abcdef 
-- expected: a

SELECT CAST(json_parse(x) as varchar(0)) from (values '"abcedef"') t(x)

-- output: abcdef 
-- expected:     // empty string

Current Behavior

See queries above.

Context

This came up when testing with Presto-native.

[kgpai]

cc: @natashasehgal @amitkdutta @rschlussel