fix double generating or_block

Author: yuyi98

vlib/v/gen/c/assign.v

@@ -103,8 +103,10 @@ fn (mut g Gen) assign_stmt(node_ ast.AssignStmt) {
 	mut return_type := ast.void_type
 	is_decl := node.op == .decl_assign
 	g.assign_op = node.op
+	g.inside_assign = true
 	defer {
 		g.assign_op = .unknown
+		g.inside_assign = false
 	}
 	op := if is_decl { token.Kind.assign } else { node.op }
 	right_expr := node.right[0]

vlib/v/gen/c/cgen.v

@@ -120,6 +120,7 @@ mut:
 	inside_ternary            int  // ?: comma separated statements on a single line
 	inside_map_postfix        bool // inside map++/-- postfix expr
 	inside_map_infix          bool // inside map<</+=/-= infix expr
+	inside_assign             bool
 	inside_map_index          bool
 	inside_opt_or_res         bool
 	inside_opt_data           bool
@@ -4123,7 +4124,7 @@ fn (mut g Gen) ident(node ast.Ident) {
 				styp := g.base_type(node.info.typ)
 				g.write('(*(${styp}*)${name}.data)')
 			}
-			if node.or_expr.kind != .absent {
+			if node.or_expr.kind != .absent && !(g.inside_assign && !g.is_assign_lhs) {
 				stmt_str := g.go_before_stmt(0).trim_space()
 				g.empty_line = true
 				g.or_block(name, node.or_expr, node.info.typ)

vlib/v/tests/option_var_2_test.v

@@ -15,10 +15,12 @@ fn test_option_var() {
 		assert true
 	}
 
+	mut counter := 0
 	val := other or {
-		println('without name')
+		counter++
 		'default'
 	}
 
 	assert val == 'default'
+	assert counter == 1
 }