Delphi's latest compiler provides a hint in these cases:
var x: Int32; begin try x := 0; x := 1; writeln(x); end. [dcc32 Hint] Project1.dpr(14): H2077 Value assigned to 'x' never used (Line 14 is the one assigning zero.) ---- On Thu, 09 Feb 2017 04:30:06 -0500 Tim Ward t...@telensa.com [firebird-support] <firebird-support@yahoogroups.com> wrote ---- It' the equivalent in a conventional programming language of saying: x = a; x = b; where the compiler is expected to know that neither a not the first assignment have any side effects other than the assignment (and where the expression b doesn't depend on the value of x)(and where x isn't volatile, ect ect). A compiler *could* detect and warn about such things (ie it's not forbidden by the laws of mathematics) but I don't think I know of any that do. And as there are good reasons for deliberately wanting to do the above it could only be a warning, not an error.