8315458: Implement JEP 463: Implicitly Declared Classes and Instance Main Method (Second Preview)

Reviewed-by: jlahoda, mcimadamore, vromero, rriggs, alanb, mchung

test/langtools/tools/javac/ImplicitClass/SourceLevelErrorPosition.java

@@ -0,0 +1,13 @@
+/**
+ * @test /nodynamiccopyright/
+ * @bug 8310314
+ * @summary Ensure proper error position for the "implicit classes not supported" error
+ * @compile/fail/ref=SourceLevelErrorPosition.out -XDrawDiagnostics SourceLevelErrorPosition.java
+ */
+class Nested {}
+void main() {
+    System.err.println("");
+}
+void test() {
+    System.err.println("");
+}