Emit (E7xxx)

The last step of kagari build writes the checked program into the .kagari file and verifies it. It runs only on a program without errors from the earlier checks.

E7001 missing-main

Error. The root module has no fn main(), so the engine has nothing to run at boot. main is the plain fn in the root file that describes the game system.

// main.kix: a root file with a story but no `fn main()`
#[entry]
#[scene]
pushdown fn Start() {
    s!(t!["Hello."]);
}

Fix: add fn main() -> System { … } to the root file, returning the game’s System.

E7002 function-too-large

Error. A function needs more than 65 535 registers, or more code words than the bytecode can address. Each local and temporary of a function takes a register, so this happens only for enormous generated functions.

// A function that keeps more than 65 535 locals alive at once.
pub fn huge() -> u32 {
    let a0 = 0u32;
    let a1 = 1u32;
    // … up to a65999 …
    let mut s = 0u32;
    s = s + a0;
    s = s + a1;
    // … up to a65999 …
    s
}

This snippet is abbreviated: a real trigger spells out all 66 000 lets and uses each of them later. Locals that are never used do not take registers.

Fix: split the function into several smaller functions.

E7003 invalid-bytecode

Error. An internal compiler error: the emitted bytecode fails the load-time verifier. The message names the verifier’s complaint. No correct program should produce it.

error[E7003]: internal compiler error: the emitted bytecode fails verification: …

This snippet is illustrative: it shows the shape of the message, since no correct compiler produces this code from any program.

Fix: report a bug with the program that triggers it.