diff --git a/crates/aiken-lang/src/expr.rs b/crates/aiken-lang/src/expr.rs
index b5dab82f..36cfb1f0 100644
--- a/crates/aiken-lang/src/expr.rs
+++ b/crates/aiken-lang/src/expr.rs
@@ -382,6 +382,11 @@ pub enum UntypedExpr {
         text: Box<Self>,
     },
 
+    TraceIfFalse {
+        location: Span,
+        value: Box<Self>,
+    },
+
     When {
         location: Span,
         subjects: Vec<Self>,
@@ -510,7 +515,8 @@ impl UntypedExpr {
         match self {
             Self::PipeLine { expressions, .. } => expressions.last().location(),
             Self::Trace { then, .. } => then.location(),
-            Self::Fn { location, .. }
+            Self::TraceIfFalse { location, .. }
+            | Self::Fn { location, .. }
             | Self::Var { location, .. }
             | Self::Int { location, .. }
             | Self::ErrorTerm { location, .. }
diff --git a/crates/aiken-lang/src/format.rs b/crates/aiken-lang/src/format.rs
index a6e71b00..9b8cd0d3 100644
--- a/crates/aiken-lang/src/format.rs
+++ b/crates/aiken-lang/src/format.rs
@@ -800,6 +800,8 @@ impl<'comments> Formatter<'comments> {
             }
 
             UntypedExpr::ErrorTerm { .. } => "error".to_doc(),
+
+            UntypedExpr::TraceIfFalse { value, .. } => self.trace_if_false(value),
         };
 
         commented(document, comments)
@@ -814,6 +816,10 @@ impl<'comments> Formatter<'comments> {
         }
     }
 
+    pub fn trace_if_false<'a>(&mut self, value: &'a UntypedExpr) -> Document<'a> {
+        docvec![self.wrap_unary_op(value), "?"]
+    }
+
     pub fn trace<'a>(
         &mut self,
         kind: &'a TraceKind,
diff --git a/crates/aiken-lang/src/tipo/expr.rs b/crates/aiken-lang/src/tipo/expr.rs
index ac5686e4..52019b78 100644
--- a/crates/aiken-lang/src/tipo/expr.rs
+++ b/crates/aiken-lang/src/tipo/expr.rs
@@ -225,6 +225,7 @@ impl<'a, 'b> ExprTyper<'a, 'b> {
             | UntypedExpr::TupleIndex { .. }
             | UntypedExpr::UnOp { .. }
             | UntypedExpr::Var { .. }
+            | UntypedExpr::TraceIfFalse { .. }
             | UntypedExpr::When { .. } => Ok(()),
         }
     }
@@ -361,6 +362,10 @@ impl<'a, 'b> ExprTyper<'a, 'b> {
                 value,
                 op,
             } => self.infer_un_op(location, value, op),
+
+            UntypedExpr::TraceIfFalse { value, location } => {
+                self.infer_trace_if_false(*value, location)
+            }
         }
     }