dont run invariant for default construction

contracts.dd

@@ -149,7 +149,7 @@ $(H2 In, Out and Inheritance)
 	contracts.
 	)
 
-$(H2 Invariants)
+$(H2 $(LNAME2 Invariants, Invariants))
 
 	$(P Invariants are used to specify characteristics of a class or struct that
 	always must be true (except while executing a member function).
@@ -163,6 +163,12 @@ class Date
     int day;
     int hour;
 
+    this(int d, int h)
+    {
+        day = d;
+        hour = h;
+    }
+
     invariant()
     {
         assert(1 <= day && day <= 31);
@@ -185,6 +191,10 @@ class Date
 	$(LI postconditions)
 	)
 
+	$(P The invariant is not checked if the class or struct is implicitly constructed using
+        the default $(CODE .init) value.
+        )
+
 	$(P The code in the invariant may not call any public non-static members
 	of the class or struct, either directly or indirectly.
 	Doing so will result in a stack overflow, as the invariant will wind
@@ -212,7 +222,7 @@ class Foo
 }
 ------
 
-	The invariant can be checked with an <code>assert()</code> expression:
+	The invariant can be checked with an $(CODE assert()) expression:
 
 	$(OL
 	$(LI classes need to pass a class object)
@@ -235,7 +245,9 @@ assert(&s);               // check that struct S invariant holds
 
 	$(P There can be only one $(I Invariant) per class or struct.)
 
-	$(P When compiling for release, the invariant code is not generated, and the compiled program runs at maximum speed.)
+	$(P When compiling for release, the invariant code is not generated, and the compiled program runs at maximum speed.
+	The compiler is free to assume the invariant holds true, regardless of whether code is generated for it or not, and
+	may optimize code accordingly.)
 
 $(H2 References)