diff --git a/tool/src/org/antlr/v4/semantics/BasicSemanticChecks.java b/tool/src/org/antlr/v4/semantics/BasicSemanticChecks.java
index 25722cb18..846c33fa2 100644
--- a/tool/src/org/antlr/v4/semantics/BasicSemanticChecks.java
+++ b/tool/src/org/antlr/v4/semantics/BasicSemanticChecks.java
@@ -191,6 +191,11 @@ public class BasicSemanticChecks extends GrammarTreeVisitor {
 		//if ( ok ) g.ast.setOption(ID.getText(), value);
 	}
 
+	@Override
+	public void defineToken(GrammarAST ID) {
+		checkTokenDefinition(ID.token);
+	}
+
 	@Override
 	public void elementOption(GrammarASTWithOptions elem, GrammarAST ID, GrammarAST valueAST) {
 		String v = null;
@@ -315,20 +320,14 @@ public class BasicSemanticChecks extends GrammarTreeVisitor {
 		}
 	}
 
-	void checkTokenAlias(Token tokenID) {
+	void checkTokenDefinition(Token tokenID) {
 		String fileName = tokenID.getInputStream().getSourceName();
-		if ( Character.isLowerCase(tokenID.getText().charAt(0)) ) {
+		if ( !Character.isUpperCase(tokenID.getText().charAt(0)) ) {
 			g.tool.errMgr.grammarError(ErrorType.TOKEN_NAMES_MUST_START_UPPER,
 									   fileName,
 									   tokenID,
 									   tokenID.getText());
 		}
-		if ( !g.isCombined() ) {
-			g.tool.errMgr.grammarError(ErrorType.CANNOT_ALIAS_TOKENS,
-									   fileName,
-									   tokenID,
-									   tokenID.getText());
-		}
 	}
 
 	/** Check option is appropriate for grammar, rule, subrule */