Fixes

Author: lolgab

compiler/src/dotty/tools/dotc/coverage/Serializer.scala

@@ -110,7 +110,7 @@ object Serializer:
         fullClassName,
         classType,
         method,
-        sourceRoot.resolve(sourcePath)
+        sourceRoot.resolve(sourcePath).normalize()
       )
       val start: Int = lines.next().toInt
       val end: Int = lines.next().toInt

compiler/src/dotty/tools/dotc/transform/InstrumentCoverage.scala

@@ -275,7 +275,9 @@ class InstrumentCoverage extends MacroTransform with IdentityDenotTransformer:
         InstrumentedParts.singleExprTree(coverageCall, transformed)
 
     override def transform(tree: Tree)(using Context): Tree =
-      lastCompiledFiles += tree.sourcePos.source.file.absolute.jpath.toString
+      val path = tree.sourcePos.source.file.absolute.jpath
+      if path != null then lastCompiledFiles += path.toString
+
       inContext(transformCtx(tree)) { // necessary to position inlined code properly
         tree match
           // simple cases