From 1fb863e50169df9f97221f058281148aeab955a1 Mon Sep 17 00:00:00 2001
From: Morgan Bazalgette <morgan@morganbaz.com>
Date: Sun, 8 Dec 2024 12:20:25 +0100
Subject: [PATCH] fix(gnovm): in op_binary, return typed booleans where
 appropriate

---
 gnovm/pkg/gnolang/op_binary.go | 35 +++++++++++++++++-----------------
 gnovm/tests/files/bool8.gno    | 17 +++++++++++++++++
 2 files changed, 34 insertions(+), 18 deletions(-)
 create mode 100644 gnovm/tests/files/bool8.gno

diff --git a/gnovm/pkg/gnolang/op_binary.go b/gnovm/pkg/gnolang/op_binary.go
index 6d26fa7ce54..3477fc61bdb 100644
--- a/gnovm/pkg/gnolang/op_binary.go
+++ b/gnovm/pkg/gnolang/op_binary.go
@@ -71,6 +71,17 @@ func (m *Machine) doOpLand() {
 	lv.SetBool(lv.GetBool() && rv.GetBool())
 }
 
+// setMaybeUntypedBool sets lv to b; it will be untyped if both lv and rv are
+// untyped; otherwise, it will be a typed bool.
+func setMaybeUntypedBool(lv, rv *TypedValue, b bool) {
+	tp := BoolType
+	if isUntyped(lv.T) && isUntyped(rv.T) {
+		tp = UntypedBoolType
+	}
+	lv.T, lv.V = tp, nil
+	lv.SetBool(b)
+}
+
 func (m *Machine) doOpEql() {
 	m.PopExpr()
 
@@ -82,9 +93,7 @@ func (m *Machine) doOpEql() {
 	}
 	// set result in lv.
 	res := isEql(m.Store, lv, rv)
-	lv.T = UntypedBoolType
-	lv.V = nil
-	lv.SetBool(res)
+	setMaybeUntypedBool(lv, rv, res)
 }
 
 func (m *Machine) doOpNeq() {
@@ -99,9 +108,7 @@ func (m *Machine) doOpNeq() {
 
 	// set result in lv.
 	res := !isEql(m.Store, lv, rv)
-	lv.T = UntypedBoolType
-	lv.V = nil
-	lv.SetBool(res)
+	setMaybeUntypedBool(lv, rv, res)
 }
 
 func (m *Machine) doOpLss() {
@@ -116,9 +123,7 @@ func (m *Machine) doOpLss() {
 
 	// set the result in lv.
 	res := isLss(lv, rv)
-	lv.T = UntypedBoolType
-	lv.V = nil
-	lv.SetBool(res)
+	setMaybeUntypedBool(lv, rv, res)
 }
 
 func (m *Machine) doOpLeq() {
@@ -133,9 +138,7 @@ func (m *Machine) doOpLeq() {
 
 	// set the result in lv.
 	res := isLeq(lv, rv)
-	lv.T = UntypedBoolType
-	lv.V = nil
-	lv.SetBool(res)
+	setMaybeUntypedBool(lv, rv, res)
 }
 
 func (m *Machine) doOpGtr() {
@@ -150,9 +153,7 @@ func (m *Machine) doOpGtr() {
 
 	// set the result in lv.
 	res := isGtr(lv, rv)
-	lv.T = UntypedBoolType
-	lv.V = nil
-	lv.SetBool(res)
+	setMaybeUntypedBool(lv, rv, res)
 }
 
 func (m *Machine) doOpGeq() {
@@ -167,9 +168,7 @@ func (m *Machine) doOpGeq() {
 
 	// set the result in lv.
 	res := isGeq(lv, rv)
-	lv.T = UntypedBoolType
-	lv.V = nil
-	lv.SetBool(res)
+	setMaybeUntypedBool(lv, rv, res)
 }
 
 func (m *Machine) doOpAdd() {
diff --git a/gnovm/tests/files/bool8.gno b/gnovm/tests/files/bool8.gno
new file mode 100644
index 00000000000..9efbbbe6da2
--- /dev/null
+++ b/gnovm/tests/files/bool8.gno
@@ -0,0 +1,17 @@
+package main
+
+// results from comparisons should not be untyped bools
+
+var a interface{} = true
+
+func main() {
+	buf := "hello="
+	isEqual(a, (buf[len(buf)-1] == '='))
+}
+
+func isEqual(v1, v2 interface{}) {
+	println("v1 == v2", v1 == v2)
+}
+
+// Output:
+// v1 == v2 true