.NET decompiled assembly has an '&' after the type producing build error

Question

I have inherited a few assemblies which as far as I know were produced using Visual Studio 2005, .NET Framework 1.1(?), and VB.NET. Unfortunately, the source code is no longer available to me. As a result, I have used dotPeek to decompile the assemblies (as C#) and attempt to reverse engineer the projects. The resulting source code has a few lines that look similar to:

// ISSUE: explicit reference operation
// ISSUE: variable of a reference type
string& szDataDescr = @str;

The 'string&' is foreign to me (and Visual Studio too apparently). Visual Studio 2015 is not recognizing this as valid, and I am getting compilation errors. Is the '&' something that dotPeek has added, or is it some legacy .NET construct that was valid way back then? Similar comment appears everywhere the 'type&' pattern is used, so I assume it is associated.

Check http://stackoverflow.com/questions/11067395/what-is-the-ampersand-character-at-the-end-of-an-object-type on more about the & — Kees C. Bakker, Jan 05 '17 at 22:34
You are using a pretty crappy decompiler, you got what you paid for. It is formally legal in MSIL, creating a reference to a variable is supported by C++/CLI. But not in VB.NET or C#, variable references break the abstraction of a property. If it was actually written in C++/CLI then, well, stop right now and do this the correct way. Use a telephone next. — Hans Passant, Jan 05 '17 at 23:32

score 2 · Accepted Answer · edited May 23 '17 at 12:33

The & sign after a type name indicates that it's a reference type, and the @ before a variable name generates a reference to that variable.

If you tried to compile the code, you'll get an error because the compiler treats & as the bitwise and, and will complain that you used a type as if it were a variable. But that's ok because you didn't get it from a C# source file.

Best solution is to use a different decompiler.

ILSpy: http://ilspy.net/
.Net Code Reflect: http://www.devextras.com/decompiler/
.Net Reflector: http://www.red-gate.com/products/dotnet-development/reflector/

Check here for more info on what the & does in IL.

.NET decompiled assembly has an '&' after the type producing build error

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