From a80538426fc6df3385e9567064d32b4b45a81669 Mon Sep 17 00:00:00 2001
From: Ryo Nihei <nihei.dev@gmail.com>
Date: Fri, 30 Jul 2021 23:41:24 +0900
Subject: Detect unused-symbol error

When there are productions and terminals that are cannot be reached from the start symbol, the compiler reports an error.
---
 driver/parser_test.go | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

(limited to 'driver/parser_test.go')

diff --git a/driver/parser_test.go b/driver/parser_test.go
index 73d8fac..e32e34c 100644
--- a/driver/parser_test.go
+++ b/driver/parser_test.go
@@ -148,6 +148,46 @@ bar_text: "bar";
 				),
 			),
 		},
+		// Production `b` is unused.
+		{
+			specSrc: `
+a
+    : foo
+    ;
+b
+    : foo;
+foo: "foo";
+`,
+			src:     `foo`,
+			specErr: true,
+		},
+		// Terminal `bar` is unused.
+		{
+			specSrc: `
+s
+    : foo
+    ;
+foo: "foo";
+bar: "bar";
+`,
+			src:     `foo`,
+			specErr: true,
+		},
+		// Production `b` and terminal `bar` is unused.
+		{
+			specSrc: `
+a
+    : foo
+    ;
+b
+    : bar
+    ;
+foo: "foo";
+bar: "bar";
+`,
+			src:     `foo`,
+			specErr: true,
+		},
 		{
 			specSrc: `
 mode_tran_seq
@@ -258,6 +298,9 @@ bar: "bar";
 		{
 			specSrc: `
 s
+    : foo
+    ;
+foo
     : "foo" #ast #(s $1...)
     ;
 `,
-- 
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