diff --git a/dyaml/constructor.d b/dyaml/constructor.d
index 8a86773..ef3b532 100644
--- a/dyaml/constructor.d
+++ b/dyaml/constructor.d
@@ -550,7 +550,7 @@ ubyte[] constructBinary(ref Node node)
             throw new Exception("Unable to decode base64 value: " ~ e.msg);
         }
     }
-    catch(UtfException e)
+    catch(UTFException e)
     {
         throw new Exception("Unable to decode base64 value: " ~ e.msg);
     }
diff --git a/dyaml/exception.d b/dyaml/exception.d
index 8d0f6d9..3ec6cf4 100644
--- a/dyaml/exception.d
+++ b/dyaml/exception.d
@@ -24,7 +24,7 @@ class YAMLException : Exception
 }
 
 ///Position in a YAML stream, used for error messages.
-align(1) struct Mark
+struct Mark
 {
     private:
         ///Line number.
@@ -49,6 +49,8 @@ align(1) struct Mark
         }
 }
 
+static assert(Mark.sizeof == 4, "Unexpected Mark size");
+
 package:
 //Base class of YAML exceptions with marked positions of the problem.
 abstract class MarkedYAMLException : YAMLException
diff --git a/dyaml/node.d b/dyaml/node.d
index 2433e5b..83cfdf8 100644
--- a/dyaml/node.d
+++ b/dyaml/node.d
@@ -200,6 +200,9 @@ struct Node
         //Node collection style. Used to remember style this node was loaded with.
         CollectionStyle collectionStyle = CollectionStyle.Invalid;
 
+        static assert(Value.sizeof <= 24, "Unexpected YAML value size");
+        static assert(Node.sizeof <= 48, "Unexpected YAML node size");
+
     public:
         /**
          * Construct a Node from a value.
@@ -1271,17 +1274,32 @@ struct Node
         }
 
         ///Compare with another _node.
-        const int opCmp(ref const Node node)
+        int opCmp(ref const Node node) const
         {
             return cmp!true(node);
         }
 
         //Compute hash of the node.
-        const hash_t toHash() 
+        hash_t toHash() const nothrow @safe
         {
-            const tagHash = tag_.isNull ? 0 : tag_.toHash();
-            //Variant toHash is not const at the moment, so we need to const-cast.
-            return tagHash + (cast(Value)value_).toHash();
+            // Hack to allow const nothrow @safe. 
+            // Should be rewritten once std.variant is fixed.
+            hash_t unsafeHash() nothrow @trusted
+            {
+                const tagHash = tag_.isNull ? 0 : tag_.toHash();
+                //Variant toHash is not nothrow at the moment, so we need to catch 
+                //an exception that is never thrown.
+                try
+                {
+                    //Variant toHash is not const at the moment, so we need to const-cast.
+                    return tagHash + (cast(Value)value_).toHash();
+                }
+                catch(Exception e)
+                {
+                    assert(false, "Unexpected exception caught");
+                }
+            }
+            return unsafeHash();
         }
 
     package:
diff --git a/dyaml/reader.d b/dyaml/reader.d
index 17cda41..8964348 100644
--- a/dyaml/reader.d
+++ b/dyaml/reader.d
@@ -315,7 +315,7 @@ final class Reader
         void handleLoadCharsException(Exception e, ulong oldPosition)
         {
             try{throw e;}
-            catch(UtfException e)
+            catch(UTFException e)
             {
                 const position = stream_.position;
                 throw new ReaderException(format("Unicode decoding error between bytes ",
diff --git a/dyaml/scanner.d b/dyaml/scanner.d
index cbcbae5..ee7e417 100644
--- a/dyaml/scanner.d
+++ b/dyaml/scanner.d
@@ -1609,7 +1609,7 @@ final class Scanner
             {
                 throw new Error("While scanning a " ~ name, startMark, e.msg, mark);
             }
-            catch(UtfException e)
+            catch(UTFException e)
             {
                 throw new Error("While scanning a " ~ name, startMark, e.msg, mark);
             }
diff --git a/dyaml/zerostring.d b/dyaml/zerostring.d
index cee2cba..990995a 100644
--- a/dyaml/zerostring.d
+++ b/dyaml/zerostring.d
@@ -36,7 +36,7 @@ struct ZeroString(string TypeName)
         }
 
         ///Get the string.
-        @property string get() const
+        @property string get() const nothrow @trusted
         in{assert(!isNull());}
         body
         {
@@ -51,12 +51,12 @@ struct ZeroString(string TypeName)
         }
 
         ///Compute a hash.
-        hash_t toHash() const
+        hash_t toHash() const nothrow @safe
         in{assert(!isNull);}
         body
         {
             auto str = get();
-            return typeid(string).getHash(&str);
+            return getHash(str);
         }
 
         ///Compare with another string.
@@ -68,5 +68,14 @@ struct ZeroString(string TypeName)
         }
 
         ///Is this string null (invalid)?
-        @property bool isNull() const {return str_ is null;}
+        @property bool isNull() const nothrow @safe {return str_ is null;}
+
+    private:
+        ///Hack to allow toHash to be @safe.
+        //
+        //To remove this hack, need a typeid(string).getHash() replacement that does not take a pointer.
+        hash_t getHash(ref string str) const nothrow @trusted
+        {
+            return typeid(string).getHash(&str);
+        }
 }