compiler: use type `unresolved` for unresolved consts

vlib/compiler/aparser.v

@@ -756,9 +756,9 @@ fn (p mut Parser) const_decl() {
 		if p.first_pass() {
 			p.table.register_const(name, typ, p.mod, is_pub)
 		}
-		// Check to see if this constant exists, and is void. If so, try and get the type again:
+		// Check to see if this constant exists, and is unresolved. If so, try and get the type again:
 		if my_const := p.v.table.find_const(name) {
-			if my_const.typ == 'void' {
+			if my_const.typ == 'unresolved' {
 				for i, v in p.v.table.consts {
 					if v.name == name {
 						p.v.table.consts[i].typ = typ

vlib/compiler/expression.v

@@ -457,7 +457,7 @@ fn (p mut Parser) name_expr() string {
 		// First pass, the function can be defined later.
 		if p.first_pass() {
 			p.next()
-			return 'void'
+			return 'unresolved'
 		}
 		// exhaused all options type,enum,const,mod,var,fn etc
 		// so show undefined error (also checks typos)
@@ -680,7 +680,7 @@ fn (p mut Parser) handle_operator(op string, typ string,cpostfix string, ph int,
 		p.cgen.set_placeholder(ph, '${typ}_${cpostfix}(')
 		p.gen(')')
 	}
-	else {
+	else if typ != 'unresolved' {
 		p.error('operator $op not defined on `$typ`')
 	}
 }

vlib/v/tests/const_test.v

@@ -2,6 +2,8 @@ pub const (
 	// c = a // TODO
 	a = b
 	b = 1
+	d = (e / 2) + 7
+	e = 9
 )
 
 struct Foo {
@@ -10,5 +12,6 @@ struct Foo {
 
 fn test_const() {
 	assert a == 1
+	assert d == 11
 	// assert c == 1 // TODO: This will not build yet
 }