diff --git a/src/distPlus/expressionTree/ExpressionTree.re b/src/distPlus/expressionTree/ExpressionTree.re
index 2611a432..ca57c14f 100644
--- a/src/distPlus/expressionTree/ExpressionTree.re
+++ b/src/distPlus/expressionTree/ExpressionTree.re
@@ -1,31 +1,6 @@
 open ExpressionTypes.ExpressionTree;
 
-let rec toString: node => string =
-  fun
-  | `SymbolicDist(d) => SymbolicDist.T.toString(d)
-  | `RenderedDist(_) => "[renderedShape]"
-  | `AlgebraicCombination(op, t1, t2) =>
-    Operation.Algebraic.format(op, toString(t1), toString(t2))
-  | `PointwiseCombination(op, t1, t2) =>
-    Operation.Pointwise.format(op, toString(t1), toString(t2))
-  | `Normalize(t) => "normalize(k" ++ toString(t) ++ ")"
-  | `Truncate(lc, rc, t) =>
-    Operation.T.truncateToString(lc, rc, toString(t))
-  | `Render(t) => toString(t)
-  | `Symbol(t) => "Symbol: " ++ t
-  | `FunctionCall(name, args) =>
-    "[Function call: ("
-    ++ name
-    ++ (args |> E.A.fmap(toString) |> Js.String.concatMany(_, ","))
-    ++ ")]"
-  | `Function(args, internal) =>
-    "[Function: ("
-    ++ (args |> Js.String.concatMany(_, ","))
-    ++ toString(internal)
-    ++ ")]"
-  | `Array(_) => "Array"
-  | `Hash(_) => "Hash"
-
+let toString = ExpressionTreeBasic.toString;
 let envs = (samplingInputs, environment) => {
   {samplingInputs, environment, evaluateNode: ExpressionTreeEvaluator.toLeaf};
 };
@@ -42,5 +17,5 @@ let toShape = (samplingInputs, environment, node: node) => {
 
 let runFunction = (samplingInputs, environment, inputs, fn: PTypes.Function.t) => {
   let params = envs(samplingInputs, environment);
-  PTypes.Function.run(params, inputs, fn)
-}
+  PTypes.Function.run(params, inputs, fn);
+};
diff --git a/src/distPlus/expressionTree/ExpressionTreeBasic.re b/src/distPlus/expressionTree/ExpressionTreeBasic.re
new file mode 100644
index 00000000..27d5aab4
--- /dev/null
+++ b/src/distPlus/expressionTree/ExpressionTreeBasic.re
@@ -0,0 +1,35 @@
+open ExpressionTypes.ExpressionTree;
+
+let rec toString: node => string =
+  fun
+  | `SymbolicDist(d) => SymbolicDist.T.toString(d)
+  | `RenderedDist(_) => "[renderedShape]"
+  | `AlgebraicCombination(op, t1, t2) =>
+    Operation.Algebraic.format(op, toString(t1), toString(t2))
+  | `PointwiseCombination(op, t1, t2) =>
+    Operation.Pointwise.format(op, toString(t1), toString(t2))
+  | `Normalize(t) => "normalize(k" ++ toString(t) ++ ")"
+  | `Truncate(lc, rc, t) =>
+    Operation.T.truncateToString(lc, rc, toString(t))
+  | `Render(t) => toString(t)
+  | `Symbol(t) => "Symbol: " ++ t
+  | `FunctionCall(name, args) =>
+    "[Function call: ("
+    ++ name
+    ++ (args |> E.A.fmap(toString) |> Js.String.concatMany(_, ","))
+    ++ ")]"
+  | `Function(args, internal) =>
+    "[Function: ("
+    ++ (args |> Js.String.concatMany(_, ","))
+    ++ toString(internal)
+    ++ ")]"
+  | `Array(a) =>
+    "[" ++ (a |> E.A.fmap(toString) |> Js.String.concatMany(_, ",")) ++ "]"
+  | `Hash(h) =>
+    "{"
+    ++ (
+      h
+      |> E.A.fmap(((name, value)) => name ++ ":" ++ toString(value))
+      |> Js.String.concatMany(_, ",")
+    )
+    ++ "}";
diff --git a/src/distPlus/typeSystem/Fns.re b/src/distPlus/typeSystem/Fns.re
index e49f434c..5c5fb426 100644
--- a/src/distPlus/typeSystem/Fns.re
+++ b/src/distPlus/typeSystem/Fns.re
@@ -1,7 +1,9 @@
 open TypeSystem;
 
-let wrongInputsError = r => {
-  Error("Wrong inputs");
+let wrongInputsError = (r: array(typedValue)) => {
+  let inputs = r |> E.A.fmap(TypedValue.toString) |>Js.String.concatMany(_, ",");
+  Js.log3("Inputs were", inputs, r);
+  Error("Wrong inputs. The inputs were:" ++ inputs);
 };
 
 let to_: (float, float) => result(node, string) =
@@ -46,6 +48,7 @@ let makeDistFloat = (name, fn) =>
     ~run=
       fun
       | [|`SamplingDist(a), `Float(b)|] => fn(a, b)
+      | [|`RenderedDist(a), `Float(b)|] => fn(`RenderedDist(a), b)
       | e => wrongInputsError(e),
     (),
   );
@@ -55,6 +58,7 @@ let makeRenderedDistFloat = (name, fn) =>
     ~name,
     ~outputType=`RenderedDistribution,
     ~inputTypes=[|`RenderedDistribution, `Float|],
+    ~shouldCoerceTypes=true,
     ~run=
       fun
       | [|`RenderedDist(a), `Float(b)|] => fn(a, b)
@@ -70,6 +74,7 @@ let makeDist = (name, fn) =>
     ~run=
       fun
       | [|`SamplingDist(a)|] => fn(a)
+      | [|`RenderedDist(a)|] => fn(`RenderedDist(a))
       | e => wrongInputsError(e),
     (),
   );
diff --git a/src/distPlus/typeSystem/TypeSystem.re b/src/distPlus/typeSystem/TypeSystem.re
index b6f54b46..654d3e98 100644
--- a/src/distPlus/typeSystem/TypeSystem.re
+++ b/src/distPlus/typeSystem/TypeSystem.re
@@ -36,6 +36,22 @@ type functions = array(_function);
 type inputNodes = array(node);
 
 module TypedValue = {
+  let rec toString: typedValue => string =
+    fun
+    | `SamplingDist(_) => "[sampling dist]"
+    | `RenderedDist(_) => "[rendered Shape]"
+    | `Float(f) => "Float: " ++ Js.Float.toString(f)
+    | `Array(a) =>
+      "[" ++ (a |> E.A.fmap(toString) |> Js.String.concatMany(_, ",")) ++ "]"
+    | `Hash(v) =>
+      "{"
+      ++ (
+        v
+        |> E.A.fmap(((name, value)) => name ++ ":" ++ toString(value))
+        |> Js.String.concatMany(_, ",")
+      )
+      ++ "}";
+
   let rec fromNode = (node: node): result(typedValue, string) =>
     switch (ExpressionTypes.ExpressionTree.toFloatIfNeeded(node)) {
     | `SymbolicDist(`Float(r)) => Ok(`Float(r))
@@ -51,7 +67,7 @@ module TypedValue = {
       |> E.A.fmap(((name, t)) => fromNode(t) |> E.R.fmap(r => (name, r)))
       |> E.A.R.firstErrorOrOpen
       |> E.R.fmap(r => `Hash(r))
-    | _ => Error("Wrong type")
+    | e => Error("Wrong type: " ++ ExpressionTreeBasic.toString(e))
     };
 
   // todo: Arrays and hashes
@@ -103,12 +119,12 @@ module TypedValue = {
     };
   };
 
-  let toFloat: typedValue => result(float,string) =
+  let toFloat: typedValue => result(float, string) =
     fun
     | `Float(x) => Ok(x)
     | _ => Error("Not a float");
 
-  let toArray: typedValue => result(array('a),string) =
+  let toArray: typedValue => result(array('a), string) =
     fun
     | `Array(x) => Ok(x)
     | _ => Error("Not an array");
@@ -118,12 +134,13 @@ module TypedValue = {
     | `Hash(x) => Ok(x)
     | _ => Error("Not a named item");
 
-  let toDist =
+  let toDist: typedValue => result(node,string) =
     fun
     | `SamplingDist(`SymbolicDist(c)) => Ok(`SymbolicDist(c))
     | `SamplingDist(`RenderedDist(c)) => Ok(`RenderedDist(c))
+    | `RenderedDist(c) => Ok(`RenderedDist(c))
     | `Float(x) => Ok(`SymbolicDist(`Float(x)))
-    | _ => Error("Cannot be converted into a distribution");
+    | x => Error("Cannot be converted into a distribution: " ++ toString(x));
 };
 
 module Function = {