From 936d60a2621088ba463a44c2f2d6450986022169 Mon Sep 17 00:00:00 2001
From: Eugene Burmako <xeno.by@gmail.com>
Date: Sun, 19 Jan 2014 23:00:09 +0300
Subject: SI-8158 compiler hangs printing out fancy types
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Apparently, even though the compiler has safeguards against infinite type
printouts, having a depth counter, we didn’t account for the cases when
printouts are both self-referential and self-multiplying.

For one, SI-8158 provides an example of such a type, which is a structural
type that refers to itself twice in return types of its methods. At first,
printing such a type would go deeper and deeper, but then it will hit
the depth limit and start multiply indefinitely.

This commit fixes this particular problem by recognizing self-references
as this.type’s and printing them out as such. The subsequent commit will
introduce a more general facility.
---
 test/files/neg/t8158.check          |  4 ++++
 test/files/neg/t8158/Macros_1.scala | 34 ++++++++++++++++++++++++++++++++++
 test/files/neg/t8158/Test_2.scala   | 14 ++++++++++++++
 test/files/run/t5256h.check         |  2 +-
 4 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 test/files/neg/t8158.check
 create mode 100644 test/files/neg/t8158/Macros_1.scala
 create mode 100644 test/files/neg/t8158/Test_2.scala

(limited to 'test/files')

diff --git a/test/files/neg/t8158.check b/test/files/neg/t8158.check
new file mode 100644
index 0000000000..aaa62ddea4
--- /dev/null
+++ b/test/files/neg/t8158.check
@@ -0,0 +1,4 @@
+Test_2.scala:10: error: not enough patterns for <$anon: AnyRef> offering AnyRef{def isEmpty: Boolean; def get: this.type; def unapply(x: String): this.type}: expected 1, found 0
+      case X() =>
+           ^
+one error found
diff --git a/test/files/neg/t8158/Macros_1.scala b/test/files/neg/t8158/Macros_1.scala
new file mode 100644
index 0000000000..b84e3ed8d3
--- /dev/null
+++ b/test/files/neg/t8158/Macros_1.scala
@@ -0,0 +1,34 @@
+import scala.language.experimental.macros
+import scala.reflect.macros.whitebox.Context
+
+object Max {
+  def impl(c: Context)(any: c.Expr[Any]): c.Expr[Any] = {
+    import c.universe._
+    def fail(msg: String) = c.abort(c.enclosingPosition, msg)
+    val t = c.macroApplication match {
+      case q"$_.unapply($unargs)" =>
+        /* hangs
+        */
+        q"""
+          new {
+            def isEmpty = false
+            def get = this
+            def unapply(x: String) = this
+          }.unapply($unargs)
+        """
+        /*
+        if get returns Unit or Boolean:
+        wrong number of patterns for <$anon: AnyRef> offering Unit: expected 1, found 0
+        */
+        /* straightforward
+        q"""
+          new {
+            def unapply(x: String) = true
+          }.unapply($unargs)
+        """
+        */
+      case _ => fail("bad appl")
+    }
+    c.Expr[Any](t)
+  }
+}
\ No newline at end of file
diff --git a/test/files/neg/t8158/Test_2.scala b/test/files/neg/t8158/Test_2.scala
new file mode 100644
index 0000000000..f5ac6616bb
--- /dev/null
+++ b/test/files/neg/t8158/Test_2.scala
@@ -0,0 +1,14 @@
+import scala.language.experimental.macros
+
+object X {
+  def unapply(any: Any): Any = macro Max.impl
+}
+
+class BugTest {
+  def bug(): Unit = {
+    "any" match {
+      case X() =>
+      case _ => ???
+    }
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/t5256h.check b/test/files/run/t5256h.check
index 1a4a92a684..300a40f653 100644
--- a/test/files/run/t5256h.check
+++ b/test/files/run/t5256h.check
@@ -3,5 +3,5 @@ Test.$anon$1
 java.lang.Object {
   final private val x: Int
   def x(): Int
-  def <init>(): java.lang.Object{def x(): Int}
+  def <init>(): this.type
 }
-- 
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