--- a/src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/MemoryAddress.java	Wed Jan 08 22:44:34 2020 +0100
+++ b/src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/MemoryAddress.java	Wed Jan 08 23:12:45 2020 +0000
@@ -74,7 +74,13 @@
 
     /**
      * Compares the specified object with this address for equality. Returns {@code true} if and only if the specified
-     * object is also a address, and it is equal to this address.
+     * object is also an address, and it refers to the same memory location as this address.
+     *
+     * @apiNote two addresses might be considered equal despite their associated segments differ. This
+     * can happen, for instance, if the segment associated with one address is a <em>slice</em>
+     * (see {@link MemorySegment#asSlice(long, long)}) of the segment associated with the other address. Moreover,
+     * two addresses might be considered equals despite differences in the temporal bounds associated with their
+     * corresponding segments (this is possible, for example, as a result of calls to {@link MemorySegment#acquire()}).
      *
      * @param that the object to be compared for equality with this address.
      * @return {@code true} if the specified object is equal to this address.

--- a/src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/MemoryLayout.java	Wed Jan 08 22:44:34 2020 +0100
+++ b/src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/MemoryLayout.java	Wed Jan 08 23:12:45 2020 +0000
@@ -55,14 +55,14 @@
  * <p>
  * Non-platform classes should not implement {@linkplain MemoryLayout} directly.
  *
- * <h2>Size, alignment and byte order</h2>
+ * <h2><a id = "layout-align">Size, alignment and byte order</a></h2>
  *
  * All layouts have a size; layout size for value and padding layouts is always explicitly denoted; this means that a layout description
  * always has the same size in bits, regardless of the platform in which it is used. For derived layouts, the size is computed
  * as follows:
  * <ul>
  *     <li>for a <em>finite</em> sequence layout <em>S</em> whose element layout is <em>E</em> and size is L,
- *     the size of <em>S</em> is that of <em>E, multiplied by L</em></li>
+ *     the size of <em>S</em> is that of <em>E</em>, multiplied by <em>L</em></li>
  *     <li>the size of an <em>unbounded</em> sequence layout is <em>unknown</em></li>
  *     <li>for a group layout <em>G</em> with member layouts <em>M1</em>, <em>M2</em>, ... <em>Mn</em> whose sizes are
  *     <em>S1</em>, <em>S2</em>, ... <em>Sn</em>, respectively, the size of <em>G</em> is either <em>S1 + S2 + ... + Sn</em> or
@@ -180,6 +180,9 @@
      * <li>{@code A=512} is the most strict alignment required by the x86/SV ABI (for AVX-512 data).</li>
      * </ul>
      *
+     * If no explicit alignment constraint was set on this layout (see {@link #withBitAlignment(long)}),
+     * then this method returns the <a href="#layout-align">natural alignment</a> constraint (in bits) associated with this layout.
+     *
      * @return the layout alignment constraint, in bits.
      */
     long bitAlignment();
@@ -195,6 +198,9 @@
      * <li>{@code A=64} is the most strict alignment required by the x86/SV ABI (for AVX-512 data).</li>
      * </ul>
      *
+     * If no explicit alignment constraint was set on this layout (see {@link #withBitAlignment(long)}),
+     * then this method returns the <a href="#layout-align">natural alignment</a> constraint (in bytes) associated with this layout.
+     *
      * @return the layout alignment constraint, in bytes.
      * @throws UnsupportedOperationException if {@code bitAlignment()} is not a multiple of 8.
      */
@@ -352,7 +358,16 @@
 
     /**
      * Compares the specified object with this layout for equality. Returns {@code true} if and only if the specified
-     * object is also a layout, and it is equal to this layout.
+     * object is also a layout, and it is equal to this layout. Two layouts are considered equal if they are of
+     * the same kind, have the same size, name and alignment constraints. Furthermore, depending on the layout kind, additional
+     * conditions must be satisfied:
+     * <ul>
+     *     <li>two value layouts are considered equal if they have the same endianness (see {@link ValueLayout#order()})</li>
+     *     <li>two sequence layouts are considered equal if they have the same element count (see {@link SequenceLayout#elementCount()}), and
+     *     if their element layouts (see {@link SequenceLayout#elementLayout()}) are also equal</li>
+     *     <li>two group layouts are considered equal if they are of the same kind (see {@link GroupLayout#isStruct()},
+     *     {@link GroupLayout#isUnion()}) and if their member layouts (see {@link GroupLayout#memberLayouts()}) are also equal</li>
+     * </ul>
      *
      * @param that the object to be compared for equality with this layout.
      * @return {@code true} if the specified object is equal to this layout.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/foreign/TestTypeAccess.java	Wed Jan 08 23:12:45 2020 +0000
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ *  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ *  This code is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 only, as
+ *  published by the Free Software Foundation.
+ *
+ *  This code is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  version 2 for more details (a copy is included in the LICENSE file that
+ *  accompanied this code).
+ *
+ *  You should have received a copy of the GNU General Public License version
+ *  2 along with this work; if not, write to the Free Software Foundation,
+ *  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *   Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ *  or visit www.oracle.com if you need additional information or have any
+ *  questions.
+ *
+ */
+
+/*
+ * @test
+ * @run testng TestTypeAccess
+ */
+
+import jdk.incubator.foreign.MemorySegment;
+import jdk.incubator.foreign.MemoryLayouts;
+import org.testng.annotations.*;
+
+import java.lang.invoke.VarHandle;
+import java.lang.invoke.WrongMethodTypeException;
+
+public class TestTypeAccess {
+
+    static final VarHandle INT_HANDLE = MemoryLayouts.JAVA_INT.varHandle(int.class);
+
+    @Test(expectedExceptions=ClassCastException.class)
+    public void testMemoryAddressCoordinateAsString() {
+        try (MemorySegment s = MemorySegment.allocateNative(8)) {
+            int v = (int)INT_HANDLE.get("string");
+        }
+    }
+
+    @Test(expectedExceptions=WrongMethodTypeException.class)
+    public void testMemoryCoordinatePrimitive() {
+        try (MemorySegment s = MemorySegment.allocateNative(8)) {
+            int v = (int)INT_HANDLE.get(1);
+        }
+    }
+}