parser: disallow or{} block for non-optionals

compiler/gen_c.v

@@ -29,6 +29,9 @@ fn (p mut Parser) gen_var_decl(name string, is_static bool) string {
 		// p.assigned_var = ''
 		p.cgen.set_placeholder(pos, '$typ $tmp = ')
 		p.genln(';')
+		if !typ.starts_with('Option_') {
+			p.error('`or` block cannot be applied to non-optional type')
+		}
 		typ = typ.replace('Option_', '')
 		p.next()
 		p.check(.lcbr)

compiler/tests/option_test.v

@@ -31,8 +31,12 @@ fn test_option_for_base_type_without_variable() {
 		println('yep')
 		return
 	}
-	println('nice')
-	println(val2)
+	println('$val2 should have been `none`')
+	assert false
+	// This is invalid:
+	//	x := 5 or {
+	//		return
+	//	}
 }
 
 fn test_if_opt() {