### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
Index: model/org/eclipse/jdt/internal/core/BinaryMethod.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/BinaryMethod.java,v
retrieving revision 1.106
diff -u -r1.106 BinaryMethod.java
--- model/org/eclipse/jdt/internal/core/BinaryMethod.java	28 Jun 2010 13:07:11 -0000	1.106
+++ model/org/eclipse/jdt/internal/core/BinaryMethod.java	31 Aug 2010 07:11:00 -0000
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2009 IBM Corporation and others.
+ * Copyright (c) 2000, 2010 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -183,8 +183,15 @@
 	IBinaryMethod info = (IBinaryMethod) getElementInfo();
 	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=316937
 	// Use Signature#getParameterCount() only if the argument names are not already available.
-	final int paramCount = info.getArgumentNames() == null ? info.getArgumentNames().length : 
-										Signature.getParameterCount(new String(info.getMethodDescriptor()));
+	int paramCount = Signature.getParameterCount(new String(info.getMethodDescriptor()));
+	if (this.isConstructor()) {
+		final IType declaringType = this.getDeclaringType();
+		if (declaringType.isMember()
+				&& !Flags.isStatic(declaringType.getFlags())) {
+			paramCount--; // remove synthetic argument from constructor param count
+		}
+	}
+
 	if (paramCount != 0) {
 		// don't try to look for javadoc for synthetic methods
 		int modifiers = getFlags();
#P org.eclipse.jdt.core.tests.model
Index: src/org/eclipse/jdt/core/tests/model/ClassFileTests.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/ClassFileTests.java,v
retrieving revision 1.49
diff -u -r1.49 ClassFileTests.java
--- src/org/eclipse/jdt/core/tests/model/ClassFileTests.java	24 Feb 2010 10:44:34 -0000	1.49
+++ src/org/eclipse/jdt/core/tests/model/ClassFileTests.java	31 Aug 2010 07:11:07 -0000
@@ -21,6 +21,7 @@
 import org.eclipse.jdt.core.search.IJavaSearchConstants;
 import org.eclipse.jdt.core.search.IJavaSearchScope;
 import org.eclipse.jdt.core.search.SearchEngine;
+import org.eclipse.jdt.internal.core.ClasspathEntry;
 
 import junit.framework.Test;
 
@@ -1543,5 +1544,55 @@
 		assertStringsEqual("Type parameter bounds signatures", 
 							"TT;\n", typeParam.getBoundsSignatures());
 	}
-
+	//https://bugs.eclipse.org/bugs/show_bug.cgi?id=316937
+	public void testBug316937() throws Exception {
+		try {
+			IJavaProject project = getJavaProject("P");
+			String[] pathAndContents = new String[] {
+					"bug316937/Foo.java",
+					"package bug316937;\n" + "public class Foo {\n"
+							+ "	class Bar {\n"
+							+ "		public Bar(int a, int b) {}\n" + "	}\n"
+							+ "}\n" };
+			addLibrary(project, "lib316937.jar", "src316937.zip",
+					pathAndContents, JavaCore.VERSION_1_5);
+			IPackageFragmentRoot packageFragRoot = project
+					.getPackageFragmentRoot(getFile("/P/lib316937.jar"));
+
+			IType type = packageFragRoot.getPackageFragment("bug316937")
+					.getClassFile("Foo.class").getType();
+			IType subType = type.getType("Bar");
+			IMethod[] methods = subType.getMethods();
+			assertEquals("Constructros", 1, methods.length);
+			IMethod method = methods[0];
+			String[] paramNames = method.getParameterNames();
+			assertStringsEqual("Type parameter names", "a\n" + "b\n",
+					paramNames);
+
+			// Remove the source attachment
+			IClasspathEntry[] rawClasspath = project.getRawClasspath();
+			for (int index = 0; index < rawClasspath.length; index++) {
+				IClasspathEntry entry = rawClasspath[index];
+				if (entry.getPath().toString().endsWith("lib316937.jar")) {
+					((ClasspathEntry) entry).sourceAttachmentPath = null;
+				}
+			}
+			project.setRawClasspath(rawClasspath, null);
+
+			packageFragRoot = project
+					.getPackageFragmentRoot(getFile("/P/lib316937.jar"));
+			type = packageFragRoot.getPackageFragment("bug316937")
+					.getClassFile("Foo.class").getType();
+			subType = type.getType("Bar");
+			methods = subType.getMethods();
+			assertEquals("Constructros", 1, methods.length);
+			method = methods[0];
+			paramNames = method.getParameterNames();
+			assertStringsEqual("Type parameter names", "a\n" + "b\n",
+					paramNames);
+		} finally {
+			removeLibrary(getJavaProject("P"), "lib316937.jar", "src316937.zip");
+		}
+	}
+	
 }