[FLINK-19362] Remove confusing comment for `DOT` operator codegen

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 1.11.0
• Fix Version/s: 1.20.0
• Component/s: Table SQL / Runtime
• Labels: auto-deprioritized-major
• Assignee: Unassigned
• Reporter: hailong wang
• Created: 22/Sep/20 14:02
• Updated: 11/Mar/24 12:43

Description

`DOT` operator codegen (ExprCodeGenerator#generateCallExpression) has comment as following:

// due to https://issues.apache.org/jira/browse/CALCITE-2162, expression such as
// "array[1].a.b" won't work now.
if (operands.size > 2) {
  throw new CodeGenException(
    "A DOT operator with more than 2 operands is not supported yet.")
}

But `array[1].a.b` actually can work for flink job. `DOT` will be transform to `RexFieldAccess` for CALCITE-2542. And `generateDot` will never be invoked  except suppporting ITEM for ROW types.

Simply, I think we can only delete the comment which is confusing.