Porting old code: Delphi compiler error E2064 Left side cannot be assigned to
Posted by jpluimers on 2021/05/27
Quoting this in full because it nicely illustrated the introduction of an intermediate variable that cannot be assigned to a second time after initial setup by the with statement: [WayBack] Embarcadero Newsgroup Archive :: embarcadero.public.delphi.ide :: Re: Delphi 2010 Compile error E2064 Left side cannot be assigned to.
Subject: Re: Delphi 2010 Compile error E2064 Left side cannot be assigned to Posted by: Uwe Schuster (jediv…@bitcommander.de) Date: Sat, 10 Oct 2009 Finn Tolderlund wrote:
> I get this error in Delphi 2010 with the code below:
> But if I remove the()from the line, it compiles and executes ok.
> Is it a bug in the compiler?
> …
>with (Pal.palPalEntry[i]) do // Compile error: E2064 Left side cannot be assigned to
>with Pal.palPalEntry[i] do // Works fineThis is no bug, because the parenthesis generates an intermediate
non-addressable value and D2010 does not longer allow write access to intermediate values with “with”.—
Uwe
This also might explain Delphi 10.2 Tokyo introduced a “with” warning: for most “with” statements, W1048 is raised ([RSP-17326] with statements generate W1048 unsafe typecast warning – Embarcadero Technologies), assuming that the intermediate is a pointer variable.
–jeroen
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