an ambiguity in c89 which will never be fixed

A deep dive into an ambiguous edge case in the C89 standard regarding implicit function declarations and scope. When a parameter name shadows a function identifier inside a function prototype's array declarator (e.g., int f(int f[sizeof(f())])), GCC and Clang disagree on whether it's legal. The ambiguity stems from the standard's vague use of 'innermost block' — it's unclear whether this means block scope, file scope, or function prototype scope. Since implicit function declarations were removed in C99, this ambiguity was never resolved and never will be. The post also includes a plea to stop using C89 given that C11 has been available for over 15 years.

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