.NET compiler and “Not all code paths return a value”

Question

Why in code like below is the .NET compiler not able to establish that all code paths do return a value?

bool Test(bool param) {
    bool test = true;
    if         


        

Answer 1

Let's backward analyze the code:

Problem: Code doesn't return any value.

Question: Where in code a value is returned?

Answer: Just at the last line.

Conclusion: So that line of code (last line) should always return a value.

Question: Does last line always return a value?

Answer: No, it only returns value if test is false while it has been set to true at the first line.

Conclusion: As compiler says, this function never returns a value while it is supposed to return bool.