Merge branch 'fix-underlying' of https://github.com/dotty-staging/dotty into fix-underlying

Author: odersky

compiler/src/dotty/tools/dotc/core/Types.scala

@@ -4164,7 +4164,7 @@ object Types {
     private var myStableHash: Byte = 0
     private var myGround: Byte = 0
 
-    private var myisStableRunId: RunId = NoRunId
+    private var myIsStableRunId: RunId = NoRunId
     private var myIsStable: Boolean = uninitialized
 
     private var myEvalRunId: RunId = NoRunId