From a87ac8664bcbc8b365eda38abde0ea921e59566b Mon Sep 17 00:00:00 2001
From: Ivan Kochurkin <kvanttt@gmail.com>
Date: Tue, 6 Oct 2015 17:39:01 +0300
Subject: [PATCH] Error in case of mode conflicts with token. fixed #996

---
 .../antlr/v4/test/tool/TestSymbolIssues.java  | 15 +++++++++++++
 .../antlr/v4/semantics/SemanticPipeline.java  |  2 ++
 .../org/antlr/v4/semantics/SymbolChecks.java  | 22 ++++++++++++-------
 tool/src/org/antlr/v4/tool/ErrorType.java     |  6 +++++
 4 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/tool-testsuite/test/org/antlr/v4/test/tool/TestSymbolIssues.java b/tool-testsuite/test/org/antlr/v4/test/tool/TestSymbolIssues.java
index 6934f2cb1..ec0fc4576 100644
--- a/tool-testsuite/test/org/antlr/v4/test/tool/TestSymbolIssues.java
+++ b/tool-testsuite/test/org/antlr/v4/test/tool/TestSymbolIssues.java
@@ -116,10 +116,25 @@ public class TestSymbolIssues extends BaseTest {
 		"warning(" + ErrorType.TOKEN_NAME_REASSIGNMENT.code + "): E.g4:3:4: token name A is already defined\n"
 	};
 
+	static String[] F = {
+		// INPUT
+		"lexer grammar F;\n" +
+		"A: 'a';\n" +
+		"mode M1;\n" +
+		"A1: 'a';\n" +
+		"mode M2;\n" +
+		"A2: 'a';\n" +
+		"M1: 'b';\n",
+
+		// YIELDS
+		"error(" + ErrorType.MODE_CONFLICTS_WITH_TOKEN.code + "): F.g4:3:0: mode M1 conflicts with token with same name\n"
+	};
+
     @Test public void testA() { super.testErrors(A, false); }
     @Test public void testB() { super.testErrors(B, false); }
 	@Test public void testD() { super.testErrors(D, false); }
 	@Test public void testE() { super.testErrors(E, false); }
+	@Test public void testF() { super.testErrors(F, false); }
 
 	@Test public void testStringLiteralRedefs() throws Exception {
 		String grammar =
diff --git a/tool/src/org/antlr/v4/semantics/SemanticPipeline.java b/tool/src/org/antlr/v4/semantics/SemanticPipeline.java
index 3561f91a8..49143d429 100644
--- a/tool/src/org/antlr/v4/semantics/SemanticPipeline.java
+++ b/tool/src/org/antlr/v4/semantics/SemanticPipeline.java
@@ -128,6 +128,8 @@ public class SemanticPipeline {
 							 collector.tokenIDRefs, collector.terminals);
 		}
 
+		symcheck.checkForModeConflicts(g);
+
 		assignChannelTypes(g, collector.channelDefs);
 
 		// CHECK RULE REFS NOW (that we've defined rules in grammar)
diff --git a/tool/src/org/antlr/v4/semantics/SymbolChecks.java b/tool/src/org/antlr/v4/semantics/SymbolChecks.java
index b280f4008..c665ee7b3 100644
--- a/tool/src/org/antlr/v4/semantics/SymbolChecks.java
+++ b/tool/src/org/antlr/v4/semantics/SymbolChecks.java
@@ -31,14 +31,8 @@
 package org.antlr.v4.semantics;
 
 import org.antlr.v4.parse.ANTLRParser;
-import org.antlr.v4.tool.Alternative;
-import org.antlr.v4.tool.Attribute;
-import org.antlr.v4.tool.AttributeDict;
-import org.antlr.v4.tool.ErrorManager;
-import org.antlr.v4.tool.ErrorType;
-import org.antlr.v4.tool.Grammar;
-import org.antlr.v4.tool.LabelElementPair;
-import org.antlr.v4.tool.Rule;
+import org.antlr.v4.runtime.Token;
+import org.antlr.v4.tool.*;
 import org.antlr.v4.tool.ast.GrammarAST;
 
 import java.util.Collection;
@@ -269,6 +263,18 @@ public class SymbolChecks {
 		}
 	}
 
+	public void checkForModeConflicts(Grammar g) {
+		if (g.isLexer()) {
+			LexerGrammar lexerGrammar = (LexerGrammar)g;
+			for (String modeName : lexerGrammar.modes.keySet()) {
+				if (g.getTokenType(modeName) != Token.INVALID_TYPE) {
+					Rule rule = ((Collection<Rule>)lexerGrammar.modes.get(modeName)).iterator().next();
+					g.tool.errMgr.grammarError(ErrorType.MODE_CONFLICTS_WITH_TOKEN, g.fileName, rule.ast.parent.getToken(), modeName);
+				}
+			}
+		}
+	}
+
 	// CAN ONLY CALL THE TWO NEXT METHODS AFTER GRAMMAR HAS RULE DEFS (see semanticpipeline)
 
 	public void checkRuleArgs(Grammar g, List<GrammarAST> rulerefs) {
diff --git a/tool/src/org/antlr/v4/tool/ErrorType.java b/tool/src/org/antlr/v4/tool/ErrorType.java
index 4868931de..6e39c202f 100644
--- a/tool/src/org/antlr/v4/tool/ErrorType.java
+++ b/tool/src/org/antlr/v4/tool/ErrorType.java
@@ -955,6 +955,12 @@ public enum ErrorType {
 	 * <p>custom channels are not supported in combined grammars</p>
 	 */
 	CHANNELS_BLOCK_IN_COMBINED_GRAMMAR(164, "custom channels are not supported in combined grammars", ErrorSeverity.ERROR),
+	/**
+	 * Compiler Error 165.
+	 *
+	 * <p>mode <em>name</em> conflicts with token with same name</p>
+	 */
+	MODE_CONFLICTS_WITH_TOKEN(165, "mode <arg> conflicts with token with same name", ErrorSeverity.ERROR),
 
 	NONCONFORMING_LR_RULE(169, "rule <arg> is left recursive but doesn't conform to a pattern ANTLR can handle", ErrorSeverity.ERROR),