Record bigint feature use from parser

PiperOrigin-RevId: 326120519

Author: JohnLuck77

src/com/google/javascript/jscomp/parsing/parser/Parser.java

@@ -2395,6 +2395,10 @@ private LiteralExpressionTree parseLiteralExpression() {
       recordFeatureUsed(Feature.NUMERIC_SEPARATOR);
     }
 
+    if (literal.type == TokenType.BIGINT) {
+      recordFeatureUsed(Feature.BIGINT);
+    }
+
     return new LiteralExpressionTree(getTreeLocation(start), literal);
   }
 

test/com/google/javascript/jscomp/parsing/ParserTest.java

@@ -3993,6 +3993,12 @@ public void testBigIntLiteralWarning() {
         "This language feature is only supported for ECMASCRIPT_2020 mode or better: bigint");
   }
 
+  @Test
+  public void testBigIntFeatureRecorded() {
+    parse("1n;");
+    expectFeatures(Feature.BIGINT);
+  }
+
   @Test
   public void testBigIntLiteralInCall() {
     parse("alert(1n)");