Diagnostics

The v0.40.x cycle added or formalized four conditional diagnostics. Each one targets a specific, common mistake and points at the fix.

ARIA-IF-001 — stray else

A leading else or else if with no preceding if:

else {                          // ERROR ARIA-IF-001
    println("orphan");
};

Before this diagnostic, a stray else fell through to expression parsing and produced a confusing "Expected expression / found token else" cascade. Now the parser recognizes the orphaned else directly and tells you it has no matching if. Fix: add the if clause it belongs to, or delete the stray else.

ARIA-IF-002 — assignment used as a condition

An assignment (=) where a condition is expected — almost always a typo for the equality test ==:

if (x = 3i32) { ... };          // ERROR ARIA-IF-002: did you mean `==`?

Because Nitpick conditions are strictly bool, an assignment could never be a valid condition, so the compiler can confidently suggest ==. This fires for both if and else if conditions. The equality test is unaffected:

if (x == 3i32) { ... };         // OK

ARIA-IF-003 — if used as an expression

An if statement placed where a value is expected — an initializer, a function argument, or a return position:

int32:x = if (c) { 1i32 } else { 2i32 };   // ERROR ARIA-IF-003

if is a statement and never yields a value. The diagnostic points you at the two value-producing conditionals:

int32:x = is (c) : 1i32 : 2i32;            // the is ternary
int32:y = pick (c) { (true){ give 1i32; }, (*){ give 2i32; } };  // pick + give

while and for in expression position keep the older generic "this is a statement" hint, because they have no value-producing counterpart.

ARIA-IS-001 — incompatible is arms

The two arms of an is ternary have incompatible types:

int32:x = is (c) : 1i32 : "two";           // ERROR ARIA-IS-001

Both arms must share a common type, which becomes the type of the whole expression. Integer arms of different widths are fine (the narrower is widened); mixing a number with a string is not. Fix: make both arms the same kind of value.

Summary