forward-port ClassfileParserTest from Scala 2

Co-authored-by: Lukas Rytz <[email protected]>

Author: 2 people

compiler/test/dotty/tools/backend/jvm/ClassfileParserTest.scala

@@ -0,0 +1,54 @@
+package dotty.tools.backend.jvm
+
+// painful to do Java reflection stuff without this
+import scala.language.unsafeNulls
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+import java.lang.reflect.Member
+
+class ClassfileParserTest {
+  @Test
+  def noConstantPoolLag(): Unit = {
+    def constNames(ms: List[Member]) = ms.collect {
+      case f if f.getName.startsWith("CONSTANT_") => f.getName
+    }.sorted
+
+    val toDotc = Map(
+      "CONSTANT_INTERFACE_METHODREF" -> "CONSTANT_INTFMETHODREF",
+      "CONSTANT_INVOKE_DYNAMIC" -> "CONSTANT_INVOKEDYNAMIC",
+      "CONSTANT_METHOD_HANDLE" -> "CONSTANT_METHODHANDLE",
+      "CONSTANT_METHOD_TYPE" -> "CONSTANT_METHODTYPE",
+      "CONSTANT_NAME_AND_TYPE" -> "CONSTANT_NAMEANDTYPE",
+    ).withDefault(x => x)
+
+    val asmConsts = constNames(Class.forName("scala.tools.asm.Symbol").getDeclaredFields.toList)
+      .map(_.stripSuffix("_TAG"))
+      .map(toDotc)
+      .::("CONSTANT_UNICODE")
+      .sorted
+    // in the Scala 2 version of this test, we also use Java reflection to get the constant
+    // names out of ClassfileConstants. in Dotty, the constants are `inline val`s, invisible
+    // to Java reflection, so we hardcode them here
+    assertEquals(asmConsts, List(
+      // do not add to this list without also making the corresponding change
+      // in ClassfileConstants! that would defeat the purpose of the test
+      "CONSTANT_CLASS",
+      "CONSTANT_DOUBLE",
+      "CONSTANT_FIELDREF",
+      "CONSTANT_FLOAT",
+      "CONSTANT_INTEGER",
+      "CONSTANT_INTFMETHODREF",
+      "CONSTANT_INVOKEDYNAMIC",
+      "CONSTANT_LONG",
+      "CONSTANT_METHODHANDLE",
+      "CONSTANT_METHODREF",
+      "CONSTANT_METHODTYPE",
+      "CONSTANT_NAMEANDTYPE",
+      "CONSTANT_STRING",
+      "CONSTANT_UNICODE",
+      "CONSTANT_UTF8",
+    ))
+  }
+}