assert_static

assert_static is a compile-time assertion with a runtime fallback for dynamic facts. It is stricter than before v0.34.6 when the expression is known false at compile time.

Syntax

Both statement forms are accepted:

assert_static comptime(2i32 + 2i32 == 4i32);
assert_static x > 0i32;

When Z3 proves the condition, the statement is erased.

CTFE-known false is a hard error

As of v0.34.6, user-authored assert_static fails compilation when the compiler can see that the expression is false during CTFE or verification:

func:main = int32() {
    assert_static comptime(false);
    exit 0;
};

Diagnostic:

ARIA-075: ARIA-ASSERT-STATIC-FAIL: assert_static() expression is false at compile time

This catches literal false and evaluated comptime(false) forms before IR codegen.

Dynamic fallback remains

If the condition depends on runtime data and cannot be proven statically, assert_static may remain as a runtime guard:

func:check = NIL(int32:x) {
    assert_static x > 0i32;
    pass(NIL);
};

Use this when a property is expected but still needs a safety net outside the solver's current reach.

Difference from prove

Directive	Proven	CTFE false / disproven	Unknown or dynamic
`prove(expr);`	erased	compile error	compile error
`assert_static expr;`	erased	ARIA-075 compile error when known false	warning/runtime guard path

Built-in macro compatibility