Merge pull request #4079 from retronym/ticket/8941

SI-8941 Idempotent presentation compilation of implicit classes

5 files changed, 152 insertions, 0 deletions

diff --git a/test/files/presentation/t8941.check b/test/files/presentation/t8941.check
new file mode 100644
index 0000000000..341804903a
--- /dev/null
+++ b/test/files/presentation/t8941.check
@@ -0,0 +1,7 @@
+reload: Source.scala
+
+askType at Source.scala(6,7)
+================================================================================
+[response] askTypeAt (6,7)
+scala.this.Predef.???
+================================================================================
diff --git a/test/files/presentation/t8941/Runner.scala b/test/files/presentation/t8941/Runner.scala
new file mode 100644
index 0000000000..0a8923a583
--- /dev/null
+++ b/test/files/presentation/t8941/Runner.scala
@@ -0,0 +1,11 @@
+import scala.tools.nsc.interactive.tests.InteractiveTest
+
+object Test extends InteractiveTest {
+  override def runDefaultTests() {
+    // make sure typer is done.. the virtual pattern matcher might translate
+    // some trees and mess up positions. But we'll catch it red handed!
+    // sourceFiles foreach (src => askLoadedTyped(src).get)
+    super.runDefaultTests()
+  }
+
+}
diff --git a/test/files/presentation/t8941/src/Source.scala b/test/files/presentation/t8941/src/Source.scala
new file mode 100644
index 0000000000..7438cccb03
--- /dev/null
+++ b/test/files/presentation/t8941/src/Source.scala
@@ -0,0 +1,8 @@
+object Foo {
+  implicit class MatCreator(val ctx: StringContext) extends AnyVal {
+    def m(args: Any*): Unit = {
+      ctx.checkLengths(args)
+    }
+    ???/*?*/
+  }
+}
diff --git a/test/files/presentation/t8941b/IdempotencyTest.scala b/test/files/presentation/t8941b/IdempotencyTest.scala
new file mode 100644
index 0000000000..af01b36898
--- /dev/null
+++ b/test/files/presentation/t8941b/IdempotencyTest.scala
@@ -0,0 +1,73 @@
+package scala.tools.nsc
+package interactive
+package tests.core
+
+import reporters.{Reporter => CompilerReporter}
+import scala.tools.nsc.interactive.InteractiveReporter
+import scala.reflect.internal.util.SourceFile
+
+/** Determistically interrupts typechecking of `code` when a defintion named
+  * `MagicInterruptionMarker` is typechecked, and then performs a targetted
+  * typecheck of the tree at the specal comment marker marker
+  */  
+abstract class IdempotencyTest { self =>
+  private val settings = new Settings
+  settings.usejavacp.value = true
+
+  private object Break extends scala.util.control.ControlThrowable
+
+  private val compilerReporter: CompilerReporter = new InteractiveReporter {
+    override def compiler = self.compiler
+  }
+
+  object compiler extends Global(settings, compilerReporter) {
+    override def checkForMoreWork(pos: Position) {
+    }
+    override def signalDone(context: Context, old: Tree, result: Tree) {
+      // println("signalDone: " + old.toString.take(50).replaceAll("\n", "\\n"))
+      if (!interrupted && analyzer.lockedCount == 0 && interruptsEnabled && shouldInterrupt(result)) {
+        interrupted = true
+        val typed = typedTreeAt(markerPosition)
+        checkTypedTree(typed)
+        throw Break
+      }
+      super.signalDone(context, old, result)
+    }
+
+    // we're driving manually using our own thread, disable the check here.
+    override def assertCorrectThread() {}
+  }
+
+  import compiler._
+
+  private var interrupted = false
+
+  // Extension points
+  protected def code: String
+  protected def shouldInterrupt(tree: Tree): Boolean = {
+    tree.symbol != null && tree.symbol.name.toString == "MagicInterruptionMarker"
+  }
+  protected def checkTypedTree(tree: Tree): Unit = {}
+  
+
+  private val source: SourceFile = newSourceFile(code)
+  private def markerPosition: Position = source.position(code.indexOf("/*?*/"))
+
+  def assertNoProblems() {
+    val problems = getUnit(source).get.problems
+    assert(problems.isEmpty, problems.mkString("\n"))
+  }
+
+  def show() {
+    reloadSource(source)
+    try {
+      typedTree(source, true)
+      assert(false, "Expected to break out of typechecking.")
+    } catch {
+      case Break => // expected
+    }
+    assertNoProblems()
+  }
+
+  def main(args: Array[String]) { show() }
+}
diff --git a/test/files/presentation/t8941b/Test.scala b/test/files/presentation/t8941b/Test.scala
new file mode 100644
index 0000000000..7269a14286
--- /dev/null
+++ b/test/files/presentation/t8941b/Test.scala
@@ -0,0 +1,53 @@
+import scala.tools.nsc.interactive.tests.core.IdempotencyTest
+
+// At the time of writing this test, removing any part of `enterExistingSym` 
+// leads to a failure.
+object Test {
+  def main(args: Array[String]) {
+    test("""
+      object Foo {
+        def term {
+          def foo(c: String = "") = c
+          class MagicInterruptionMarker
+          foo()/*?*/
+        }
+      }
+    """)
+
+    test("""
+      object Foo {
+        def term {
+          def foo = 42
+          class MagicInterruptionMarker
+          foo/*?*/
+        }
+      }
+    """)
+
+    test("""
+      object Foo {
+        def term {
+          lazy val foo = 42
+          class MagicInterruptionMarker
+          foo/*?*/
+        }
+      }
+    """)
+
+    test("""
+      object Foo {
+        implicit class C(val a: String) extends AnyVal
+        class MagicInterruptionMarker
+        ""/*?*/
+      }
+    """)
+  }
+
+  def test(code0: String) {
+    val t = new IdempotencyTest {
+      def code = code0
+    }
+    t.show()
+  }
+}
+