Fix signalling of success/failure (by @mthom)

src/machine/mod.rs

@@ -60,7 +60,6 @@ use std::sync::atomic::AtomicBool;
 
 use self::config::MachineConfig;
 use self::parsed_results::*;
-use tokio::runtime::Runtime;
 use rand::rngs::StdRng;
 use rand::SeedableRng;
 
@@ -118,6 +117,7 @@ include!(concat!(env!("OUT_DIR"), "/libraries.rs"));
 pub static BREAK_FROM_DISPATCH_LOOP_LOC: usize = 0;
 pub static INSTALL_VERIFY_ATTR_INTERRUPT: usize = 1;
 pub static VERIFY_ATTR_INTERRUPT_LOC: usize = 2;
+pub static LIB_QUERY_SUCCESS: usize = 3;
 
 pub struct MachinePreludeView<'a> {
     pub indices: &'a mut IndexStore,
@@ -397,13 +397,14 @@ impl Machine {
     }
 
     pub(crate) fn add_impls_to_indices(&mut self) {
-        let impls_offset = self.code.len() + 3;
+        let impls_offset = self.code.len() + 4;
 
         self.code.extend(
             vec![
                 Instruction::BreakFromDispatchLoop,
                 Instruction::InstallVerifyAttr,
                 Instruction::VerifyAttrInterrupt,
+                Instruction::BreakFromDispatchLoop, // the location of LIB_QUERY_SUCCESS
                 Instruction::ExecuteTermGreaterThan,
                 Instruction::ExecuteTermLessThan,
                 Instruction::ExecuteTermGreaterThanOrEqual,