Inconsistent query formatting with equals function in type argument #65055
Description
Describe what's wrong
Parsing of type arguments is not consistent with formatting. Operator functions (e.g.: equals) can be parsed as types, because Decimal(12,10) is the same as equals(1,2) from the parser perspective. However when outputting the AST, ASTFunction outputs 1 = 2 instead of equals(1,2), which cannot be parsed as a type. Thus formatQuery(formatQuery(<query with equals(1,2) as type>)) fails to parse the result of the inner formatQuery.
ip-10-2-3-206.eu-west-1.compute.internal :) SELECT formatQuery('ALTER TABLE src (MODIFY COLUMN `B` Nullable(equals(\'test6\',toNullable(5))))')
SELECT formatQuery('ALTER TABLE src (MODIFY COLUMN `B` Nullable(equals(\'test6\',toNullable(5))))')
Query id: 9455f2f0-5533-4c56-b48a-ef1ac05ea1ac
┌─formatQuery('ALTER TABLE src (MODIFY COLUMN `B` Nullable(equals(\'test6\',toNullable(5))))')─┐
1. │ ALTER TABLE src
(MODIFY COLUMN `B` Nullable('test6' = toNullable(5))) │
└──────────────────────────────────────────────────────────────────────────────────────────────┘
1 row in set. Elapsed: 0.019 sec.
ip-10-2-3-206.eu-west-1.compute.internal :) SELECT formatQuery(formatQuery('ALTER TABLE src (MODIFY COLUMN `B` Nullable(equals(\'test6\',toNullable(5))))'))
SELECT formatQuery(formatQuery('ALTER TABLE src (MODIFY COLUMN `B` Nullable(equals(\'test6\',toNullable(5))))'))
Query id: 7a57b554-4c82-4f28-a40d-d31aff95441d
Elapsed: 0.025 sec.
Received exception:
Code: 62. DB::Exception: Syntax error: failed at position 59 ('toNullable') (line 2, col 43): toNullable(5))). Expected one of: literal, NULL, NULL, number, Bool, TRUE, FALSE, string literal: In scope SELECT formatQuery(formatQuery('ALTER TABLE src (MODIFY COLUMN `B` Nullable(equals(\'test6\',toNullable(5))))')). (SYNTAX_ERROR)
ip-10-2-3-206.eu-west-1.compute.internal :)
Found by fuzzer.
How to reproduce
SELECT formatQuery('ALTER TABLE src (MODIFY COLUMN `B` Nullable(equals(\'test6\',toNullable(5))))');
SELECT formatQuery(formatQuery('ALTER TABLE src (MODIFY COLUMN `B` Nullable(equals(\'test6\',toNullable(5))))'));
Expected behavior
If the original query can be parsed, then the formatted query can also be parsed.