Inline initialization of integer array

Question

These two lines compile:

uint8[5] foo = [0,0,0,0,0];
int[5] foo = [1,0,0,0,0];

My question is, why do the following two lines not compile and how can I fix them?

int[5] foo = [1,-1,0,0,0];

Error: Unable to deduce common type for array elements

int8[5] foo = [0,0,0,0,0];

Error: Type uint8[5] memory is not implicitly convertible to expected type int8[5] storage ref.

I assume inlining numbers only works with uint?

Solidity Version 0.3.2-9e36bdda

Answer 1

The following code compiles correctly:

uint8[5] foo1 = [0, 0, 0, 0, 0];
int[5]   foo2 = [1, 0, 0, 0, 0];
int[5]   foo3 = [int(1), int(-1), int(0), int(0), int(0)];
int8[5]  foo4 = [int8(0), int8(0), int8(0), int8(0), int8(0)];

Q: why do the following two lines not compile and how can I fix them?

A: Because the compiler cannot deduce the correct types of the array elements to match the array type. See the code above to fix the issue. Reference Solidity Documentation - Types - Explicit Conversions.

Q: I assume inlining numbers only works with uint?

A: See Solidity Documentation - Types - Type Deduction.