Why does Xojo.Core.Dictionary.HasKey(String) work?

General
1

Consider this code, which does hit the breakpoint in 2016r1

[code]Dim D As New Xojo.Core.Dictionary
Dim S As String = DefineEncoding(“a”, Nil)
Dim T As Text = “a”

D.Value(T) = T

If D.HasKey(S) Then
Break
End If[/code]

We have a string with nil encoding, which is found in the dictionary, despite the only key being a Text. String should never implicitly convert to Text, and without an encoding, should raise an exception when trying to explicitly convert. So given all this, why are S and T effectively equivalent in this example? This seems like an implied conversion. It’s convenient, no doubt, but I want to make sure I’m not relying on a bug.

2

This is intentional. The comparisons are mirroring what would happen if it were done with explicit types at compile time:

  Dim S As String = DefineEncoding("a", Nil)
  Dim T As Text = "a"
  
  If s = t Then 
    Break
  End If
3

Why would s = t if s has no encoding by which to convert to Text? Just trying to understand the reasoning here.

4

It converts in the other direction. The common type between Text and String is String.

5

So we’re seeing the implied Text to String conversion, and then String to String comparison here?

6

Yep.