#843 The implicit casting of argument to string works for Instr() and Mid() but not for Left() and Right()

[fxm (freebasic.net)]

For an UDT with a member operator Cast to String, an instance passed as argument is well implicitly converted to string when calling Instr() and Mid(), but not when calling Left() and Right():

Type UDT
  Declare Operator Cast() As String
  Dim As Integer I
End Type
Operator UDT.cast() As String
  Return Str(This.I)
End Operator

Dim As UDT u
u.I = 123

Print Mid(u, 2)
Print Instr(u, "2")
Print Left(u, 2)
Print Right(u, 2)

error 97: Ambiguous call to overloaded function, LEFT() in 'Print Left(u, 2)'
error 97: Ambiguous call to overloaded function, RIGHT() in 'Print Right(u, 2)'

[fxm (freebasic.net)]

Same behavior for ZString and WString.

Example for WString:

Type UDT
  Declare Operator Cast() Byref As Wstring
  Dim As Integer I
End Type
Operator UDT.cast() Byref As Wstring
  Static As Wstring * 21 w
  w = Wstr(This.I)
  Return w
End Operator

Dim As UDT u
u.I = 123

Print Mid(u, 2)
Print Instr(u, "2")
Print Left(u, 2)
Print Right(u, 2)

error 97: Ambiguous call to overloaded function, LEFT() in 'Print Left(u, 2)'
error 97: Ambiguous call to overloaded function, RIGHT() in 'Print Right(u, 2)'

[fxm (freebasic.net)]

That also does not work with Val().

[Jeff Marshall]

Related to [#666]

Pull request at github # 332 Allow overloads for z|w string ptr types and conversions for UDT's casting z|w string ptr types

Fixed in fbc 1.09.0 [4dda1eaab5d9c0f86e44045fcd7540dcfd57709b]

Note:
I just noticed the last message from fxm : 'that also does not work with Val()'
I didn't write any tests specifically for Val(), but this fix also addresses the issue with Val() - it's the same issue as with Left()/Right().