A serious security bug... caused by no bounds checking.

[Steven Schveighoffer]

On Thu, 10 Apr 2014 12:49:26 -0400, Tommi <tommitissari at hotmail.com> wrote:

> On Thursday, 10 April 2014 at 15:00:34 UTC, Steven Schveighoffer wrote:

>> No, the author of the @safe code expects bounds checking, it's part of  
>> the requirements. To compile his code with it off is like having a  
>> -compilergeneratedhash switch that overrides any toHash functions with  
>> a compiler generated one. You are changing the agreement between the  
>> compiler and the code.
>
> Obviously if such or any other compiler flags exist, their existence and  
> behaviour has been specified in binding agreement between the compiler  
> and the source code, and thus, no breach of contract has happened if  
> such compiler flags were used.

A compiler flag is a blunt instrument. It affects all code the compiler  
touches, which may or may not affect code that you are intending to change.

For example:

// compiled without -noboundscheck
module compiledlib;

void foo(T)(T[] x) @safe
{
    x[5] = 3;
}

...

// compiled with -noboundscheck
main() @safe
{
    foo([1,2,3]); // memory now corrupted, no warning, no runtime error.
}

-Steve