diff --git a/src/core/errors_test.go b/src/core/errors_test.go
index df8b6ae..f3963fe 100644
--- a/src/core/errors_test.go
+++ b/src/core/errors_test.go
@@ -86,6 +86,7 @@ var errs = []struct {
 	{"TypeMismatch14.q", &core.TypeMismatch{Encountered: "int", Expected: "function"}},
 	{"TypeMismatch15.q", &core.TypeMismatch{Encountered: "string", Expected: "int"}},
 	{"TypeMismatch16.q", &core.TypeMismatch{Encountered: "string", Expected: "int"}},
+	{"TypeMismatch17.q", &core.TypeMismatch{Encountered: "(int64, int64)", Expected: "int"}},
 	{"UndefinedStructField.q", &core.UndefinedStructField{Identifier: "p", FieldName: "y"}},
 	{"UnknownEnumMember.q", &core.UnknownEnumMember{EnumName: "MyEnum", MemberName: "unknown"}},
 	{"UnknownIdentifier.q", &core.UnknownIdentifier{Name: "x"}},
diff --git a/src/core/evaluateBinary.go b/src/core/evaluateBinary.go
index c2d47f6..75006c4 100644
--- a/src/core/evaluateBinary.go
+++ b/src/core/evaluateBinary.go
@@ -37,8 +37,10 @@ func (f *Function) evaluateBinary(expr *expression.Expression) (ssa.Value, error
 		return nil, err
 	}
 
-	leftStructType, leftIsStruct := types.Unwrap(leftValue.Type()).(*types.Struct)
-	rightStructType, rightIsStruct := types.Unwrap(rightValue.Type()).(*types.Struct)
+	leftType := leftValue.Type()
+	rightType := rightValue.Type()
+	leftStructType, leftIsStruct := types.Unwrap(leftType).(*types.Struct)
+	rightStructType, rightIsStruct := types.Unwrap(rightType).(*types.Struct)
 
 	if leftIsStruct && rightIsStruct && leftStructType == types.String && rightStructType == types.String {
 		switch expr.Token.Kind {
@@ -67,6 +69,10 @@ func (f *Function) evaluateBinary(expr *expression.Expression) (ssa.Value, error
 		return nil, errors.New(InvalidStructOperation, f.File, expr.Token)
 	}
 
+	if !types.IsCastable(leftType, rightType) && !types.IsCastable(rightType, leftType) {
+		return nil, errors.New(&TypeMismatch{Encountered: leftType.Name(), Expected: rightType.Name()}, f.File, left.Source())
+	}
+
 	v := &ssa.BinaryOp{
 		Left:    leftValue,
 		Right:   rightValue,
diff --git a/src/core/testdata/TypeMismatch17.q b/src/core/testdata/TypeMismatch17.q
new file mode 100644
index 0000000..32e126f
--- /dev/null
+++ b/src/core/testdata/TypeMismatch17.q
@@ -0,0 +1,7 @@
+main() {
+	assert f() == 1
+}
+
+f() -> (int, int) {
+	return 1, 2
+}
\ No newline at end of file
diff --git a/src/types/IsCastable.go b/src/types/IsCastable.go
index 100006b..da4890a 100644
--- a/src/types/IsCastable.go
+++ b/src/types/IsCastable.go
@@ -2,7 +2,7 @@ package types
 
 // IsCastable returns true if the `a` type can be casted to the `b` type using an explicit cast.
 func IsCastable(a Type, b Type) bool {
-	if a == Any {
+	if a == b || a == Any {
 		return true
 	}