CSharp compile's bug?

[Guest]

bool b = true;
if(!b) goto end;
string str="str";
end:
Console.Write(str);

compiler throw error message 'unassign variable "str"'.
this error explain compiler was find variable define,
but don't execute assing sentence.
Why?Is't a bug?

 

[MSDN]

string st"str"; was not reachable

bool b = true;
string str = string.Empty;
if (!b) goto end;
str = "str";
end:
Console.Write(str);

 

[Guest]

string st"str"; was not reachable

bool b = true;
string str = string.Empty;
if (!b) goto end;
str = "str";
end:
Console.Write(str);

if not reachable so compiler should throw not find error.
but it throw unassign error.
so i think it's a bug.

 

[Jon Skeet [C# MVP]]

bool b = true;
if(!b) goto end;
string str="str";
end:
Console.Write(str);

compiler throw error message 'unassign variable "str"'.
this error explain compiler was find variable define,
but don't execute assing sentence.
Why?Is't a bug?

No, it's not a bug. The C# compiler doesn't attempt to verify that the
"if" condition will never be satisfied unless the expression is a
constant, which in this case it isn't.

The variable str isn't definitely assigned as per the C# language
specification, hence the error.