Compiler Errors
* Detected during compilation: These errors occur because the code violates the language's syntax rules or semantic constraints. The compiler cannot understand the code and therefore cannot generate machine instructions.
* Language definition violation: These errors represent a fundamental problem with the code's structure, not just a logical error.
* Examples: Missing semicolons, incorrect function signatures, undefined variables, type mismatches.
Program Bugs
* Detected during runtime: These errors occur when the program executes and encounters a situation it was not designed to handle. The code itself might be syntactically correct but produces unexpected or incorrect results.
* Logical errors: These errors are not violations of the language definition but rather flawed logic in the program.
* Examples: Division by zero, accessing an array out of bounds, incorrect calculations, deadlocks.
The Grey Area:
There are situations where the line blurs. For example, if a program attempts to access memory that is not allocated to it, this is technically a runtime error (segmentation fault). However, it can be argued that this is a violation of the language's memory management rules, which is a language definition issue.
Your Point:
You're right to say that errors the compiler cannot catch or easily generate code for should be considered language definition violations. This means the language itself is not robust enough to prevent these errors from occurring.
Examples:
* Unbounded recursion: A recursive function without a base case can lead to a stack overflow, a runtime error. However, the language could be designed to detect and prevent such situations.
* Memory leaks: Unmanaged memory allocation can lead to memory exhaustion, another runtime error. Languages could be designed to automatically manage memory, reducing the possibility of such errors.
Conclusion:
While the distinction between compiler errors and program bugs is generally clear, there are situations where the line blurs. Errors that the compiler cannot catch or easily generate code for should be considered language definition violations, as they indicate weaknesses in the language's design. These issues should be addressed to make the language more robust and reduce the occurrence of runtime errors.