### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
Index: compiler/org/eclipse/jdt/internal/compiler/lookup/ClassScope.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ClassScope.java,v
retrieving revision 1.146
diff -u -r1.146 ClassScope.java
--- compiler/org/eclipse/jdt/internal/compiler/lookup/ClassScope.java	10 Apr 2007 19:03:10 -0000	1.146
+++ compiler/org/eclipse/jdt/internal/compiler/lookup/ClassScope.java	2 May 2007 16:59:42 -0000
@@ -307,6 +307,10 @@
 			char[][] className = CharOperation.deepCopy(enclosingType.compoundName);
 			className[className.length - 1] =
 				CharOperation.concat(className[className.length - 1], referenceContext.name, '$');
+			ReferenceBinding existingType = packageBinding.getType0(className[className.length - 1]);
+			if (existingType != null)
+				// report the error against the parent - its still safe to answer the member type
+				this.parent.problemReporter().duplicateNestedType(referenceContext);
 			referenceContext.binding = new MemberTypeBinding(className, this, enclosingType);
 		}
 
#P org.eclipse.jdt.core.tests.compiler
Index: src/org/eclipse/jdt/core/tests/compiler/regression/CollisionCase.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/CollisionCase.java,v
retrieving revision 1.7
diff -u -r1.7 CollisionCase.java
--- src/org/eclipse/jdt/core/tests/compiler/regression/CollisionCase.java	29 Mar 2006 03:50:22 -0000	1.7
+++ src/org/eclipse/jdt/core/tests/compiler/regression/CollisionCase.java	2 May 2007 16:59:43 -0000
@@ -66,4 +66,23 @@
 		"foo.bar cannot be resolved to a type\n" + 
 		"----------\n");
 }
+// http://bugs.eclipse.org/bugs/show_bug.cgi?id=84886
+public void test003() {
+	this.runNegativeTest(
+		new String[] {
+			"X.java",
+			"class X {\n" + 
+			"	class MyFoo {\n" + 
+			"		class Bar {}\n" + 
+			"	}\n" + 
+			"	static class MyFoo$Bar {}\n" + 
+			"}\n",
+		},
+		"----------\n" + 
+		"1. ERROR in X.java (at line 5)\n" + 
+		"	static class MyFoo$Bar {}\n" + 
+		"	             ^^^^^^^^^\n" + 
+		"Duplicate nested type MyFoo$Bar\n" + 
+		"----------\n");
+}
 }