diff --git a/gnovm/pkg/gnolang/op_assign.go b/gnovm/pkg/gnolang/op_assign.go
index 5e841fb18fd..b42bb4744c0 100644
--- a/gnovm/pkg/gnolang/op_assign.go
+++ b/gnovm/pkg/gnolang/op_assign.go
@@ -20,6 +20,9 @@ func (m *Machine) doOpDefine() {
 				}
 			}
 		}
+		if !m.PreprocessorMode && isUntyped(rvs[i].T) && rvs[i].T.Kind() != BoolKind {
+			panic("untyped conversion should not happen at runtime")
+		}
 		ptr.Assign2(m.Alloc, m.Store, m.Realm, rvs[i], true)
 	}
 }
@@ -41,6 +44,9 @@ func (m *Machine) doOpAssign() {
 				}
 			}
 		}
+		if !m.PreprocessorMode && isUntyped(rvs[i].T) && rvs[i].T.Kind() != BoolKind {
+			panic("untyped conversion should not happen at runtime")
+		}
 		lv.Assign2(m.Alloc, m.Store, m.Realm, rvs[i], true)
 	}
 }
diff --git a/gnovm/pkg/gnolang/op_decl.go b/gnovm/pkg/gnolang/op_decl.go
index c9c04ccf76d..6dbae2d3edf 100644
--- a/gnovm/pkg/gnolang/op_decl.go
+++ b/gnovm/pkg/gnolang/op_decl.go
@@ -29,35 +29,31 @@ func (m *Machine) doOpValueDecl() {
 		} else {
 			tv = rvs[i]
 		}
-		if nt != nil {
-			if nt.Kind() == InterfaceKind {
-				if isUntyped(tv.T) {
-					ConvertUntypedTo(&tv, nil)
-				} else {
-					// keep type as is.
+
+		if isUntyped(tv.T) {
+			if !s.Const {
+				if !m.PreprocessorMode && rvs[i].T.Kind() != BoolKind {
+					panic("untyped conversion should not happen at runtime")
 				}
-			} else {
-				if isUntyped(tv.T) {
-					ConvertUntypedTo(&tv, nt)
-				} else {
-					if debug {
-						if nt.TypeID() != tv.T.TypeID() &&
-							baseOf(nt).TypeID() != tv.T.TypeID() {
-							panic(fmt.Sprintf(
-								"type mismatch: %s vs %s",
-								nt.TypeID(),
-								tv.T.TypeID(),
-							))
-						}
+				ConvertUntypedTo(&tv, nil)
+			}
+		} else if nt != nil {
+			// if nt.T is an interface, maintain tv.T as-is.
+			if nt.Kind() != InterfaceKind {
+				if debug {
+					if nt.TypeID() != tv.T.TypeID() &&
+						baseOf(nt).TypeID() != tv.T.TypeID() {
+						panic(fmt.Sprintf(
+							"type mismatch: %s vs %s",
+							nt.TypeID(),
+							tv.T.TypeID(),
+						))
 					}
-					tv.T = nt
 				}
+				tv.T = nt
 			}
-		} else if s.Const {
-			// leave untyped as is.
-		} else if isUntyped(tv.T) {
-			ConvertUntypedTo(&tv, nil)
 		}
+
 		nx := &s.NameExprs[i]
 		ptr := lb.GetPointerToMaybeHeapDefine(m.Store, nx)
 		ptr.Assign2(m.Alloc, m.Store, m.Realm, tv, false)
diff --git a/gnovm/pkg/gnolang/uverse.go b/gnovm/pkg/gnolang/uverse.go
index 55791ba4900..074f7a51b66 100644
--- a/gnovm/pkg/gnolang/uverse.go
+++ b/gnovm/pkg/gnolang/uverse.go
@@ -1050,6 +1050,9 @@ func makeUverseNode() {
 				}
 			}
 
+			if isUntyped(exception.Value.T) {
+				ConvertUntypedTo(&exception.Value, nil)
+			}
 			m.PushValue(exception.Value)
 			// Recover complete; remove exceptions.
 			m.Exceptions = nil
diff --git a/gnovm/pkg/gnolang/values_conversions.go b/gnovm/pkg/gnolang/values_conversions.go
index 920ed655ec9..ce256680de6 100644
--- a/gnovm/pkg/gnolang/values_conversions.go
+++ b/gnovm/pkg/gnolang/values_conversions.go
@@ -1316,28 +1316,14 @@ func ConvertUntypedTo(tv *TypedValue, t Type) {
 	}
 	switch tv.T {
 	case UntypedBoolType:
-		if debug {
-			if t.Kind() != BoolKind {
-				panic("untyped bool can only be converted to bool kind")
-			}
-		}
 		tv.T = t
 	case UntypedRuneType:
 		ConvertUntypedRuneTo(tv, t)
 	case UntypedBigintType:
-		if preprocessing.Load() == 0 {
-			panic("untyped Bigint conversion should not happen during interpretation")
-		}
 		ConvertUntypedBigintTo(tv, tv.V.(BigintValue), t)
 	case UntypedBigdecType:
-		if preprocessing.Load() == 0 {
-			panic("untyped Bigdec conversion should not happen during interpretation")
-		}
 		ConvertUntypedBigdecTo(tv, tv.V.(BigdecValue), t)
 	case UntypedStringType:
-		if preprocessing.Load() == 0 {
-			panic("untyped String conversion should not happen during interpretation")
-		}
 		if t.Kind() == StringKind {
 			tv.T = t
 			return