Migrated from http://lampsvn.epfl.ch/trac/scala/ticket/2879
Reporter spiros
Steps to reproduce the bug:

1. Create a Scala project named zbuilder
2. Create a Scala class named Test
3. Delete the project selecting the "Delete project contents on disk" checkbox.

As a result of step 3 the project named zbuilder gets successfully deleted from Eclipse and the project's files get deleted from the filesystem.

1. Create a new project with the same name (zbuilder)
2. Create a new Scala class (HelloBuilder), edit it and save the file to compile

After step 5 we get an error dialog and various entries in the error log. The entries are two errors saying "Errors occurred during the build" and "Resource '/zbuilder/src/Test.scala' does not exist" with no stacktrace and a warning with the following entry:

eclipse.buildId=M20090917-0800
java.version=1.6.0_15
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=en_US
Framework arguments:  -product org.eclipse.epp.package.jee.product
Command-line arguments:  -os linux -ws gtk -arch x86_64 -product org.eclipse.epp.package.jee.product


Warning
Sat Jan 09 09:55:31 EET 2010
Errors running builder 'Scala Builder' on project 'zbuilder'.

org.eclipse.core.internal.resources.ResourceException: Resource '/zbuilder/src/Test.scala' does not exist.
at org.eclipse.core.internal.resources.Resource.checkExists(Resource.java:319)
at org.eclipse.core.internal.resources.Resource.checkAccessible(Resource.java:196)
at org.eclipse.core.internal.resources.File.getContents(File.java:286)
at org.eclipse.core.internal.resources.File.getContents(File.java:277)
at scala.tools.eclipse.util.EclipseFile.input(EclipseFile.scala:84)
at scala.tools.nsc.io.AbstractFile.toByteArray(AbstractFile.scala:146)
at scala.tools.nsc.io.SourceReader.read(SourceReader.scala:71)
at scala.tools.nsc.Global.getSourceFile(Global.scala:231)
at scala.tools.nsc.Global$Run$$anonfun$compileFiles$1.apply(Global.scala:820)
at scala.tools.nsc.Global$Run$$anonfun$compileFiles$1.apply(Global.scala:820)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:238)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:238)
at scala.collection.LinearSeqLike$class.foreach(LinearSeqLike.scala:97)
at scala.collection.immutable.List.foreach(List.scala:46)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:238)
at scala.collection.immutable.List.map(List.scala:46)
at scala.tools.nsc.Global$Run.compileFiles(Global.scala:820)
at scala.tools.nsc.interactive.RefinedBuildManager.update0$1(RefinedBuildManager.scala:108)
at scala.tools.nsc.interactive.RefinedBuildManager.update(RefinedBuildManager.scala:158)
at scala.tools.nsc.interactive.RefinedBuildManager.update(RefinedBuildManager.scala:83)
at scala.tools.eclipse.EclipseBuildManager.build(EclipseBuildManager.scala:120)
at scala.tools.eclipse.ScalaProject.build(ScalaProject.scala:396)
at scala.tools.eclipse.ScalaBuilder.build(ScalaBuilder.scala:87)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:627)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:170)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:201)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:253)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:256)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:309)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:341)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:140)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:238)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

See also #2878.
Tested with Eclipse 3.5.1 and SDT r20423.