What's C's biggest mistake?

[Don]

Walter Bright wrote:
> Don wrote:
>> Well, if you ask the question "what's C++'s biggest mistake?" it's 
>> much more difficult. C++'s failure to specify the ABI is enough of a 
>> reason to use C instead, I reckon. It think it's an appalling, 
>> inexcusable mistake -- it guaranteed compiled libraries 20 years later 
>> would use extern(C), not extern(C++). And that's not the worst C++ 
>> mistake.
> 
> I'd be hard pressed to come up with C++'s biggest mistake. Perhaps it 
> was failing to address the array => pointer conversion.

I think the biggest mistake was preserving backwards source-code 
compatibility with C, but _still_ managing to lose many of C's 
advantages. As a pure superset of C, it _should_ have been able to 
replace 100% of the uses of C, but failed miserably.