Sonatina internal error: duplicate root object `main` across ingot modules

[g-r-a-n-t]

fe build fails with an internal Sonatina error when an ingot contains 2+ source modules that don’t define a contract (e.g. “library/re-export” modules). It appears each such module is lowered into an EVM object named main, and multiple such modules collide.

Environment

• fe: 26.1.0
• OS: Linux x86_64 (Ubuntu 24.04.1; kernel 6.17.0-23-generic)

Minimal repro

Create a new ingot with multiple library modules and a contract:

fe.toml

[ingot]
name = "dup_main_repro"
version = "0.1.0"

src/lib.fe

pub use libmod::{self, *}
pub use libmod2::{self, *}
pub use contractmod::{self, *}

src/libmod.fe

pub fn helper() -> u256 { 1 }

src/libmod2.fe

pub fn helper2() -> u256 { 2 }

src/contractmod.fe

pub msg AMsg {
    #[selector = sol("foo()")]
    Foo -> u256,
}

pub contract A {
    recv AMsg {
        Foo -> u256 { 1 }
    }
}

Repro commands:

• fe check <dir>: succeeds
• fe build <dir>: fails

Actual result

Error: Failed to compile Sonatina bytecode: internal error: duplicate root object `main` across ingot modules

Evidence (IR contains multiple object @main)

The build can emit Sonatina IR successfully, and the .sona contains multiple main objects:

fe build <dir> --emit ir --out-dir <out-ir>
rg -n '^object @main' <out-ir>/dup_main_repro.sona

Output includes 2 matches (two object @main { ... } blocks).

Workarounds / related behavior

• fe build <dir> --contract A succeeds.
• If the ingot has exactly one non-contract module, fe build <dir> succeeds but emits extra out/main.bin / out/main.runtime.bin artifacts alongside the contract artifacts.
• Real-world example: the chz ingot has two non-contract re-export modules (src/chess.fe and src/contracts.fe), so fe build . fails but fe build . --contract <Name> works.

Expected result

Any of the following would resolve the issue:

• Do not lower non-contract modules into deployable EVM “main” objects when building an ingot.
• Or ensure those objects are uniquely named/mangled per module so multi-file ingots build.
• Or gate emission of such “main” objects behind an explicit flag/target mode.