Merge pull request #2653 from retronym/ticket/7433

SI-7433 Fix spurious warning about catching control throwable

2 files changed, 13 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/UnCurry.scala b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
index 64f4e579e1..e2ce2743f7 100644
--- a/src/compiler/scala/tools/nsc/transform/UnCurry.scala
+++ b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
@@ -187,8 +187,14 @@ abstract class UnCurry extends InfoTransform
         val keyDef   = ValDef(key, New(ObjectTpe))
         val tryCatch = Try(body, pat -> rhs)
 
-        for (Try(t, catches, _) <- body ; cdef <- catches ; if treeInfo catchesThrowable cdef)
+        import treeInfo.{catchesThrowable, isSyntheticCase}
+        for {
+          Try(t, catches, _) <- body
+          cdef <- catches
+          if catchesThrowable(cdef) && !isSyntheticCase(cdef)
+        } {
           unit.warning(body.pos, "catch block may intercept non-local return from " + meth)
+        }
 
         Block(List(keyDef), tryCatch)
       }
diff --git a/src/reflect/scala/reflect/internal/TreeInfo.scala b/src/reflect/scala/reflect/internal/TreeInfo.scala
index 3a8d3fd460..30ec555bc5 100644
--- a/src/reflect/scala/reflect/internal/TreeInfo.scala
+++ b/src/reflect/scala/reflect/internal/TreeInfo.scala
@@ -553,6 +553,12 @@ abstract class TreeInfo {
     })
   )
 
+  /** Is this CaseDef synthetically generated, e.g. by `MatchTranslation.translateTry`? */
+  def isSyntheticCase(cdef: CaseDef) = cdef.pat.exists {
+    case dt: DefTree => dt.symbol.isSynthetic
+    case _           => false
+  }
+
   /** Is this pattern node a catch-all or type-test pattern? */
   def isCatchCase(cdef: CaseDef) = cdef match {
     case CaseDef(Typed(Ident(nme.WILDCARD), tpt), EmptyTree, _) =>