Avoid NPE when printing TyperStates

Swilvan · Oct 4, 2017 · 539c203 · 539c203
1 parent 9a96ce3
commit 539c203
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/compiler/src/dotty/tools/dotc/core/TyperState.scala b/compiler/src/dotty/tools/dotc/core/TyperState.scala
@@ -165,5 +165,6 @@ class TyperState(previous: TyperState /* | Null */) extends DotClass with Showab
 
   override def toText(printer: Printer): Text = constraint.toText(printer)
 
-  def hashesStr: String = hashCode.toString + " -> " + previous.hashesStr
+  def hashesStr: String =
+    if (previous == null) "" else hashCode.toString + " -> " + previous.hashesStr
 }