diff --git a/src/compiler/clvm.rs b/src/compiler/clvm.rs
index a0b7765b..b4b31262 100644
--- a/src/compiler/clvm.rs
+++ b/src/compiler/clvm.rs
@@ -431,6 +431,16 @@ pub fn get_history_len(step: Rc<RunStep>) -> usize {
 
 /// Generically determine whether a value is truthy.
 pub fn truthy(sexp: Rc<SExp>) -> bool {
+    if NewStyleIntConversion::setting() {
+        // The previous truthy would not have taken account of all zero bit
+        // values of lengths other than zero.
+        match sexp.borrow() {
+            SExp::Atom(_, a) => { return a.len() != 0; }
+            SExp::QuotedString(_, _, a) => { return a.len() != 0; }
+            _ => { }
+        }
+    }
+
     // Fails for cons, but cons is truthy
     atom_value(sexp).unwrap_or_else(|_| bi_one()) != bi_zero()
 }
diff --git a/src/tests/classic/zero_constant_generation.rs b/src/tests/classic/zero_constant_generation.rs
index f14e44e8..98814030 100644
--- a/src/tests/classic/zero_constant_generation.rs
+++ b/src/tests/classic/zero_constant_generation.rs
@@ -35,3 +35,43 @@ fn test_fuzz_constant_gen() {
         test_parallel_run(test);
     }
 }
+
+#[test]
+fn test_truthy_in_constant_generation() {
+    let test_program = "(mod X %1 (defconst C (if %c 1 0)) X)";
+
+    let test_parallel_run = |test| {
+        let final_program_classic = test_program.replace("%1", "").replace("%c", test);
+        let final_program_23_1 = test_program
+            .replace("%1", "(include *standard-cl-23.1*)")
+            .replace("%c", test);
+        let classic = do_basic_run(&vec!["run".to_string(), final_program_classic]);
+        let new_ver = do_basic_run(&vec!["run".to_string(), final_program_23_1]);
+        let classic_output = do_basic_brun(&vec!["brun".to_string(), classic, "0x01".to_string()]);
+        let new_output = do_basic_brun(&vec!["brun".to_string(), new_ver, "0x01".to_string()]);
+        assert_eq!(classic_output, new_output);
+    };
+
+    for test in [
+        "0",
+        "\"\"",
+        "()",
+        "0x00",
+        "(concat 0 0)",
+        "(concat 0x00 0x00)",
+        "(concat 0 0x00)",
+        "(concat 1 0x00)",
+        "(concat -1 0x00)",
+        "(concat -129 0x00)",
+        "(concat 0x00 0)",
+        "(concat 0x00 1)",
+        "(concat 0x00 -1)",
+        "(concat 0x00 -129)",
+        "(concat 0x00 (sha256 0x00 0))",
+        "(concat 0x00 (sha256 0 0x00 0))",
+    ]
+    .iter()
+    {
+        test_parallel_run(test);
+    }
+}
diff --git a/src/tests/compiler/mod.rs b/src/tests/compiler/mod.rs
index 1c5db92c..2d6b6813 100644
--- a/src/tests/compiler/mod.rs
+++ b/src/tests/compiler/mod.rs
@@ -11,6 +11,7 @@ mod compiler;
 mod evaluate;
 mod fuzz;
 mod fuzz_assign;
+mod fuzz_program;
 mod optimizer;
 mod preprocessor;
 mod repl;