type checker regression on 6.1 in subtyping rules for tuple labels

Description

Swift version 6.1 (swift-6.1-RELEASE)
Target: x86_64-unknown-linux-gnu
<stdin>:3:5: error: conflicting arguments to generic parameter 'Elements' ('[(Int, (b: Int, c: Int))]' vs. '[(Int, (Int, Int))]')
1 | func f()
2 | {
3 |     for (a, (b, c)):(Int, (b:Int, c:Int)) in [(1, (2, 3))]
  |     `- error: conflicting arguments to generic parameter 'Elements' ('[(Int, (b: Int, c: Int))]' vs. '[(Int, (Int, Int))]')
4 |     {
5 |     }
<stdin>:3:58: error: conflicting arguments to generic parameter 'Self' ('[(Int, (b: Int, c: Int))]' vs. '[(Int, (Int, Int))]')
1 | func f()
2 | {
3 |     for (a, (b, c)):(Int, (b:Int, c:Int)) in [(1, (2, 3))]
  |                                                          `- error: conflicting arguments to generic parameter 'Self' ('[(Int, (b: Int, c: Int))]' vs. '[(Int, (Int, Int))]')
4 |     {
5 |     }
<stdin>:3:46: error: conflicting arguments to generic parameter 'Element' ('(Int, (b: Int, c: Int))' vs. '(Int, (Int, Int))')
1 | func f()
2 | {
3 |     for (a, (b, c)):(Int, (b:Int, c:Int)) in [(1, (2, 3))]
  |                                              `- error: conflicting arguments to generic parameter 'Element' ('(Int, (b: Int, c: Int))' vs. '(Int, (Int, Int))')
4 |     {
5 |     }

Reproduction

func f()
{
    for (a, (b, c)):(Int, (b:Int, c:Int)) in [(1, (2, 3))]
    {
    }
}

Expected behavior

it compiled on 6.0.3

Environment

Swift version 6.1 (swift-6.1-RELEASE)
Target: x86_64-unknown-linux-gnu

Additional information

No response

Start by reproducing the provided Swift snippet with Swift 6.1 and compare its result with Swift 6.0.3. Trace the type checker's subtyping and tuple-label handling for the annotated for-loop pattern. Done means the reproduction compiles without the conflicting generic-parameter diagnostics while preserving the expected tuple labels.