--- a/dmd/InExp.d	Mon Dec 14 14:50:03 2009 +0300
+++ b/dmd/InExp.d	Mon Dec 14 17:43:43 2009 +0300
@@ -6,7 +6,12 @@
 import dmd.Scope;
 import dmd.IRState;
 import dmd.BinExp;
-import dmd.TOK;
+import dmd.TOK;
+import dmd.Type;
+import dmd.TY;
+import dmd.TypeAArray;
+
+import dmd.expression.util.arrayTypeCompatible;
 
 import dmd.backend.elem;
 
@@ -14,18 +19,47 @@
 {
 	this(Loc loc, Expression e1, Expression e2)
 	{
-		assert(false);
-		super(loc, TOK.init, 0, e1, e2);
+		super(loc, TOKin, InExp.sizeof, e1, e2);
 	}
 
 	Expression semantic(Scope sc)
 	{
-		assert(false);
+		if (type)
+			return this;
+
+		super.semanticp(sc);
+
+		Expression e = op_overload(sc);
+		if (e)
+			return e;
+
+		//type = Type.tboolean;
+		Type t2b = e2.type.toBasetype();
+		if (t2b.ty != TY.Taarray)
+		{
+			error("rvalue of in expression must be an associative array, not %s", e2.type.toChars());
+			type = Type.terror;
+		}
+		else
+		{
+			TypeAArray ta = cast(TypeAArray)t2b;
+
+			// Special handling for array keys
+			if (!arrayTypeCompatible(e1.loc, e1.type, ta.index))
+			{
+				// Convert key to type of key
+				e1 = e1.implicitCastTo(sc, ta.index);
+			}
+
+			// Return type is pointer to value
+			type = ta.nextOf().pointerTo();
+		}
+		return this;
 	}
 
 	int isBit()
 	{
-		assert(false);
+		return 0;
 	}
 
 	Identifier opId()