fix: custom boolean types in conditional statements

gnovm/pkg/gnolang/gno_test.go

@@ -724,3 +724,86 @@ func TestCallFieldLHS(t *testing.T) {
 	assert.Equal(t, 2, x.X)
 	assert.Equal(t, 3, y)
 }
+
+// check nameExpr in if cond
+func TestNameExprIfCond(t *testing.T) {
+	t.Parallel()
+
+	m := NewMachine("test", nil)
+	c := `package test
+func main() {
+	v := T
+	if v {
+		println("X")
+	}
+}
+
+type C bool
+
+const (
+	F C = false
+	T C = true
+)`
+	n := MustParseFile("main.go", c)
+	m.RunFiles(n)
+	m.RunMain()
+}
+
+// check nameExpr in for cond
+func TestNameExprForCond(t *testing.T) {
+	t.Parallel()
+
+	m := NewMachine("test", nil)
+	c := `package test
+func main() {
+	v := T
+	i := 0
+	for v {
+		println("X")
+		if i > 3 {
+			break
+		}
+		i++
+	}
+}
+
+type C bool
+
+const (
+	F C = false
+	T C = true
+)`
+	n := MustParseFile("main.go", c)
+	m.RunFiles(n)
+	m.RunMain()
+}
+
+func TestInvalidAssignment(t *testing.T) {
+	t.Parallel()
+
+	defer func() {
+		if r := recover(); r != nil {
+			assert.Error(t, r.(error), "cannot use bool as test.C without explicit conversion")
+		}
+	}()
+
+	m := NewMachine("test", nil)
+	c := `package test
+func main() {
+	b := true
+	var v C = b
+	fmt.Println(v)
+}
+
+type C bool
+
+const (
+	F C = false
+	T C = true
+)
+	`
+	n := MustParseFile("main.go", c)
+	m.RunFiles(n)
+	m.RunMain()
+	assert.True(t, false) // Should not be reached because should panic
+}

gnovm/pkg/gnolang/preprocess.go

@@ -1701,13 +1701,23 @@ func Preprocess(store Store, ctx BlockNode, n Node) Node {
 
 			// TRANS_LEAVE -----------------------
 			case *ForStmt:
-				// Cond consts become bool *ConstExprs.
-				checkOrConvertType(store, last, &n.Cond, BoolType, false)
+				if nx, ok := (n.Cond).(*NameExpr); ok {
+					// Cond is named type, check if bool
+					checkNameExprType(store, last, nx, BoolType)
+				} else {
+					// Cond consts become bool *ConstExprs.
+					checkOrConvertType(store, last, &n.Cond, BoolType, false)
+				}
 
 			// TRANS_LEAVE -----------------------
 			case *IfStmt:
-				// Cond consts become bool *ConstExprs.
-				checkOrConvertType(store, last, &n.Cond, BoolType, false)
+				if nx, ok := (n.Cond).(*NameExpr); ok {
+					// Cond is named type, check if bool
+					checkNameExprType(store, last, nx, BoolType)
+				} else {
+					// Cond consts become bool *ConstExprs.
+					checkOrConvertType(store, last, &n.Cond, BoolType, false)
+				}
 
 			// TRANS_LEAVE -----------------------
 			case *RangeStmt:
@@ -2713,6 +2723,16 @@ func checkType(xt Type, dt Type, autoNative bool) {
 		dt.String()))
 }
 
+// Checks type of NameExpr
+func checkNameExprType(store Store, last BlockNode, nx *NameExpr, t Type) {
+	xt := evalStaticTypeOf(store, last, Expr(nx))
+	if dxt, ok := xt.(*DeclaredType); ok {
+		checkType(dxt.Base, t, false)
+	} else {
+		panic("cannot assign named type to primitive, or primitive to named type without conversion")
+	}
+}
+
 // Returns any names not yet defined nor predefined in expr.  These happen
 // upon transcribe:enter from the top, so value paths cannot be used.  If no
 // names are un and x is TypeExpr, evalStaticType(store,last, x) must not