From b4207e1be79d35ad79527733fcbc7ecf637a0775 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Mon, 23 Sep 2019 02:14:10 +0300
Subject: [PATCH] compiler: allow "u64_var == 0" without casting the const
 literal

---
 compiler/parser.v       | 11 +++++++----
 compiler/table.v        |  7 +++++++
 vlib/builtin/int_test.v |  1 +
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/compiler/parser.v b/compiler/parser.v
index e8dfd225cf..7713e3883c 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -62,6 +62,7 @@ mut:
 	v_script bool // "V bash", import all os functions into global space
 	var_decl_name string 	// To allow declaring the variable so that it can be used in the struct initialization
 	is_alloc   bool // Whether current expression resulted in an allocation
+	is_const_literal bool // `1`, `2.0` etc, so that `u64 == 0` works
 	cur_gen_type string // "App" to replace "T" in current generic function
 	is_vweb bool
 	is_sql bool
@@ -1463,6 +1464,7 @@ fn (p mut Parser) bterm() string {
 // also called on *, &, @, . (enum)
 fn (p mut Parser) name_expr() string {
 	p.has_immutable_field = false
+	p.is_const_literal = false
 	ph := p.cgen.add_placeholder()
 	// amp
 	ptr := p.tok == .amp
@@ -2119,10 +2121,11 @@ fn (p mut Parser) indot_expr() string {
 
 // returns resulting type
 fn (p mut Parser) expression() string {
-	if p.scanner.file_path.contains('test_test') {
-		println('expression() pass=$p.pass tok=')
-		p.print_tok()
-	}
+	p.is_const_literal = true
+	//if p.scanner.file_path.contains('test_test') {
+		//println('expression() pass=$p.pass tok=')
+		//p.print_tok()
+	//}
 	ph := p.cgen.add_placeholder()
 	mut typ := p.indot_expr()
 	is_str := typ=='string'
diff --git a/compiler/table.v b/compiler/table.v
index 3f4d5dc75e..992819f9f7 100644
--- a/compiler/table.v
+++ b/compiler/table.v
@@ -610,6 +610,13 @@ fn (p mut Parser) _check_types(got_, expected_ string, throw bool) bool {
 	if expected=='void*' && got=='int' {
 		return true
 	}
+	// Allow `myu64 == 1`
+	//if p.fileis('_test') && is_number_type(got) && is_number_type(expected)  {
+		//p.warn('got=$got exp=$expected $p.is_const_literal')
+	//}
+	if is_number_type(got) && is_number_type(expected) && p.is_const_literal {
+		return true
+	}	
 	expected = expected.replace('*', '')
 	got = got.replace('*', '')
 	if got != expected {
diff --git a/vlib/builtin/int_test.v b/vlib/builtin/int_test.v
index 56af9167cf..eae41cce39 100644
--- a/vlib/builtin/int_test.v
+++ b/vlib/builtin/int_test.v
@@ -8,6 +8,7 @@ fn test_const() {
 	assert b == true
 	assert a == 3
 	assert u == u64(1)
+	assert u == 1 // make sure this works without the cast
 }
 
 fn test_str_methods() {