From dc1c8a019a23ea1ffab9e5d7c4fd53859a07ee36 Mon Sep 17 00:00:00 2001
From: Markus Sutter <markus.sutter@mibexsoftware.com>
Date: Fri, 4 Jun 2021 08:18:18 +0200
Subject: [PATCH 1/3] Add person readable toString for PositionBridge

There are compile call paths relying on
meaningful toString impl. for error/warning
log messages. Therefor lets add toString, which is:
"concise but informative representation that is easy for a person to read."

Without this, e.g. users of https://github.com/davidB/scala-maven-plugin
get unsuitable compile problems like:
[Warn] dotty.tools.xsbt.PositionBridge@4fbdc20: match may not be exhaustive....

Example call path:
log:45, SbtLogger (sbt_inc)
log:47, Logger (sbt.util)
warn:43, Logger (sbt.util)
logWarning:159, LoggedReporter (sbt.internal.inc)
display:168, LoggedReporter (sbt.internal.inc)
log:142, LoggedReporter (sbt.internal.inc)
doReport:43, DelegatingReporter (dotty.tools.xsbt)
report:150, Reporter (dotty.tools.dotc.reporting)
issueWarning:32, report$ (dotty.tools.dotc)
warning:67, report$ (dotty.tools.dotc)
checkExhaustivity:847, SpaceEngine (dotty.tools.dotc.transform.patmat)
....
---
 sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java b/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java
index 2f20609578db..376ec6b361cb 100644
--- a/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java
+++ b/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java
@@ -39,6 +39,10 @@ public Optional<Integer> pointer() {
     public Optional<String> pointerSpace() {
       return Optional.empty();
     }
+
+    public String toString() {
+      return "";
+    }
   };
 
   public PositionBridge(SourcePosition pos, SourceFile src) {
@@ -116,4 +120,9 @@ public Optional<String> pointerSpace() {
       result.append(lineContent.charAt(i) == '\t' ? '\t' : ' ');
     return Optional.of(result.toString());
   }
+
+  @Override
+  public String toString() {
+      return pos.toString();
+  }
 }

From 2d01ba24720b6493ab3cc31f182b8456697d1219 Mon Sep 17 00:00:00 2001
From: Vadim Chelyshov <qtankle@gmail.com>
Date: Tue, 15 Jun 2021 20:38:02 +0300
Subject: [PATCH 2/3] [Bridge] Position - implement methods for accesing range

---
 .../src/dotty/tools/xsbt/PositionBridge.java  | 49 +++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java b/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java
index 376ec6b361cb..075efd5b53e6 100644
--- a/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java
+++ b/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java
@@ -125,4 +125,53 @@ public Optional<String> pointerSpace() {
   public String toString() {
       return pos.toString();
   }
+  
+  @Override
+  public Optional<Integer> startOffset() {
+    if (src.content().length == 0)
+      return Optional.empty();
+    else
+      return Optional.of(pos.start());
+  }
+
+  @Override
+  public Optional<Integer> endOffset() {
+    if (src.content().length == 0)
+      return Optional.empty();
+    else
+      return Optional.of(pos.end());
+  }
+
+  @Override
+  public Optional<Integer> startLine() {
+    if (src.content().length == 0)
+      return Optional.empty();
+    else
+      return Optional.of(pos.startLine() + 1);
+  }
+
+  @Override
+  public Optional<Integer> endLine() {
+    if (src.content().length == 0)
+      return Optional.empty();
+    else
+      return Optional.of(pos.endLine() + 1);
+  }
+
+  @Override
+  public Optional<Integer> startColumn() {
+    if (src.content().length == 0)
+      return Optional.empty();
+    else
+      return Optional.of(pos.startColumn());
+  }
+
+  @Override
+  public Optional<Integer> endColumn() {
+    if (src.content().length == 0)
+      return Optional.empty();
+    else
+      return Optional.of(pos.endColumn());
+  }
+
 }

From 38156519ffb3288d39c57beb35a1d21c6e2f07b8 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Sat, 5 Jun 2021 13:00:43 +0200
Subject: [PATCH 3/3] Drop flaky test

Fixes #12693
---
 tests/neg/i12640.scala | 17 -----------------
 1 file changed, 17 deletions(-)
 delete mode 100644 tests/neg/i12640.scala

diff --git a/tests/neg/i12640.scala b/tests/neg/i12640.scala
deleted file mode 100644
index 7946525deeeb..000000000000
--- a/tests/neg/i12640.scala
+++ /dev/null
@@ -1,17 +0,0 @@
-package x
-
-trait CpsMonad[F[_]]:
-  def pure[A](x:A): F[A]
-  def flatMap[A,B](fa:F[A])(f: A=>F[B]): F[B]
-
-abstract sealed class CpsStream[-F[_],+T]
-
-case class Cons[F[_],T](head:T, tailFun: ()=>F[CpsStream[F,T]]) extends CpsStream[F,T]
-
-case class Empty[F[_]]() extends CpsStream[F,Nothing]
-
-def unfold[S,F[_]:CpsMonad,T](s0:S)(f:S => F[Option[(S,T)]]):F[CpsStream[F,T]] =
-      summon[CpsMonad[F]].flatMap(f(s0)){
-         case Some(s1,a) => Cons(a, () => unfold(s1,f))  // error // error
-         case None => summon[CpsMonad[F]].pure(Empty[F]())
-      }
\ No newline at end of file