transformer: fix struct init comparison turning into boolean (#25724)

Author: felipensp

vlib/v/tests/structs/struct_eq_op_test.v

@@ -0,0 +1,12 @@
+struct MyInt {
+	x int
+}
+
+fn (i1 MyInt) == (i2 MyInt) bool {
+	return i1.x == i2.x
+}
+
+fn test_main() {
+	c := MyInt{30} == MyInt{2}
+	assert !c
+}

vlib/v/transformer/transformer.v

@@ -1137,7 +1137,8 @@ pub fn (mut t Transformer) infix_expr(mut node ast.InfixExpr) ast.Expr {
 				// for `a == a`, `a != a`, `struct.f != struct.f`
 				// Note: can't compare `f32` or `f64` here, as `NaN != NaN` will return true in IEEE 754
 				if node.left.type_name() == node.right.type_name()
-					&& node.left_type !in [ast.f32_type, ast.f64_type] && node.op in [.eq, .ne] {
+					&& node.left_type !in [ast.f32_type, ast.f64_type] && node.op in [.eq, .ne]
+					&& node.left !is ast.StructInit && node.right !is ast.StructInit {
 					left_name := '${node.left}'
 					right_name := '${node.right}'
 					if left_name == right_name {