C's most infamous parsing difficulty is:

    A * B;

Is it A multiplied by B, or B declared as a pointer to A? It can't be resolved without a symbol table. But there's another way that works very well: it's a declaration. The reason is simple. The multiply has no purpose, and so nobody would write that. C doesn't have metaprogramming, so it won't be generating such code as an edge case (unless using the preprocessor for metaprogramming, in which case you deserve what you get).

But there's a worse problem:

    (A) - B

Is it A minus B, or casting negative B to type A? There's just no way to know without a symbol table. One might think who would write code that has a vacuous set of parentheses around an identifier? It turns out they don't, but they write macros that parenthesize the arguments, and the preprocessed result has those vacuous parentheses.

D resolves both issues with:

1. if it parses like a declaration, it's a declaration

2. a cast expression is preceded by the keyword `cast`

and D is easy to parse without a symbol table.