diff --git a/src/tree/mod.rs b/src/tree/mod.rs
index ef5b344..3dff3b6 100644
--- a/src/tree/mod.rs
+++ b/src/tree/mod.rs
@@ -190,7 +190,7 @@ impl Node {
         match self.eval_with_context(context) {
             Ok(Value::Int(int)) => Ok(int as FloatType),
             Ok(Value::Float(float)) => Ok(float),
-            Ok(value) => Err(EvalexprError::expected_int(value)),
+            Ok(value) => Err(EvalexprError::expected_number(value)),
             Err(error) => Err(error),
         }
     }
@@ -281,7 +281,7 @@ impl Node {
         match self.eval_with_context_mut(context) {
             Ok(Value::Int(int)) => Ok(int as FloatType),
             Ok(Value::Float(float)) => Ok(float),
-            Ok(value) => Err(EvalexprError::expected_int(value)),
+            Ok(value) => Err(EvalexprError::expected_number(value)),
             Err(error) => Err(error),
         }
     }
diff --git a/tests/integration.rs b/tests/integration.rs
index 74e0c95..8f38837 100644
--- a/tests/integration.rs
+++ b/tests/integration.rs
@@ -683,105 +683,402 @@ fn test_shortcut_functions() {
     // With detour via build_operator_tree
 
     assert_eq!(
-        build_operator_tree("\"???\"").unwrap().eval_string(),
-        Ok("???".to_owned())
+        build_operator_tree("\"3.3\"").unwrap().eval_string(),
+        Ok("3.3".to_owned())
+    );
+    assert_eq!(
+        build_operator_tree("3.3").unwrap().eval_string(),
+        Err(EvalexprError::ExpectedString {
+            actual: Value::Float(3.3)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("3..3").unwrap().eval_string(),
+        Err(EvalexprError::VariableIdentifierNotFound("3..3".to_owned()))
     );
     assert_eq!(
         build_operator_tree("string")
             .unwrap()
             .eval_string_with_context(&context),
-        Ok("a string".to_string())
+        Ok("a string".to_owned())
     );
-    assert_eq!(build_operator_tree("3.3").unwrap().eval_float(), Ok(3.3));
     assert_eq!(
         build_operator_tree("3.3")
             .unwrap()
-            .eval_float_with_context(&context),
-        Ok(3.3)
+            .eval_string_with_context(&context),
+        Err(EvalexprError::ExpectedString {
+            actual: Value::Float(3.3)
+        })
     );
-    assert_eq!(build_operator_tree("3").unwrap().eval_int(), Ok(3));
     assert_eq!(
-        build_operator_tree("3")
+        build_operator_tree("3..3")
             .unwrap()
-            .eval_int_with_context(&context),
-        Ok(3)
+            .eval_string_with_context(&context),
+        Err(EvalexprError::VariableIdentifierNotFound("3..3".to_owned()))
     );
-    assert_eq!(build_operator_tree("3").unwrap().eval_number(), Ok(3.0));
-    assert_eq!(
-        build_operator_tree("3")
-            .unwrap()
-            .eval_number_with_context(&context),
-        Ok(3.0)
-    );
-    assert_eq!(
-        build_operator_tree("true").unwrap().eval_boolean(),
-        Ok(true)
-    );
-    assert_eq!(
-        build_operator_tree("true")
-            .unwrap()
-            .eval_boolean_with_context(&context),
-        Ok(true)
-    );
-    assert_eq!(
-        build_operator_tree("3,3").unwrap().eval_tuple(),
-        Ok(vec![Value::Int(3), Value::Int(3)])
-    );
-    assert_eq!(
-        build_operator_tree("3,3")
-            .unwrap()
-            .eval_tuple_with_context(&context),
-        Ok(vec![Value::Int(3), Value::Int(3)])
-    );
-    assert_eq!(
-        build_operator_tree("")
-            .unwrap()
-            .eval_empty_with_context(&context),
-        Ok(EMPTY_VALUE)
-    );
-
     assert_eq!(
         build_operator_tree("string")
             .unwrap()
             .eval_string_with_context_mut(&mut context),
         Ok("a string".to_string())
     );
+    assert_eq!(
+        build_operator_tree("3.3")
+            .unwrap()
+            .eval_string_with_context_mut(&mut context),
+        Err(EvalexprError::ExpectedString {
+            actual: Value::Float(3.3)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("3..3")
+            .unwrap()
+            .eval_string_with_context_mut(&mut context),
+        Err(EvalexprError::VariableIdentifierNotFound("3..3".to_owned()))
+    );
+
+    assert_eq!(build_operator_tree("3.3").unwrap().eval_float(), Ok(3.3));
+    assert_eq!(
+        build_operator_tree("33").unwrap().eval_float(),
+        Err(EvalexprError::ExpectedFloat {
+            actual: Value::Int(33)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("asd()").unwrap().eval_float(),
+        Err(EvalexprError::FunctionIdentifierNotFound("asd".to_owned()))
+    );
+    assert_eq!(
+        build_operator_tree("3.3")
+            .unwrap()
+            .eval_float_with_context(&context),
+        Ok(3.3)
+    );
+    assert_eq!(
+        build_operator_tree("33")
+            .unwrap()
+            .eval_float_with_context(&context),
+        Err(EvalexprError::ExpectedFloat {
+            actual: Value::Int(33)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("asd")
+            .unwrap()
+            .eval_float_with_context(&context),
+        Err(EvalexprError::VariableIdentifierNotFound("asd".to_owned()))
+    );
     assert_eq!(
         build_operator_tree("3.3")
             .unwrap()
             .eval_float_with_context_mut(&mut context),
         Ok(3.3)
     );
+    assert_eq!(
+        build_operator_tree("33")
+            .unwrap()
+            .eval_float_with_context_mut(&mut context),
+        Err(EvalexprError::ExpectedFloat {
+            actual: Value::Int(33)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("asd")
+            .unwrap()
+            .eval_float_with_context_mut(&mut context),
+        Err(EvalexprError::VariableIdentifierNotFound("asd".to_owned()))
+    );
+
+    assert_eq!(build_operator_tree("3").unwrap().eval_int(), Ok(3));
+    assert_eq!(
+        build_operator_tree("3.3").unwrap().eval_int(),
+        Err(EvalexprError::ExpectedInt {
+            actual: Value::Float(3.3)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("(,);.").unwrap().eval_int(),
+        Err(EvalexprError::VariableIdentifierNotFound(".".to_owned()))
+    );
+    assert_eq!(
+        build_operator_tree("3")
+            .unwrap()
+            .eval_int_with_context(&context),
+        Ok(3)
+    );
+    assert_eq!(
+        build_operator_tree("3.3")
+            .unwrap()
+            .eval_int_with_context(&context),
+        Err(EvalexprError::ExpectedInt {
+            actual: Value::Float(3.3)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("(,);.")
+            .unwrap()
+            .eval_int_with_context(&context),
+        Err(EvalexprError::VariableIdentifierNotFound(".".to_owned()))
+    );
     assert_eq!(
         build_operator_tree("3")
             .unwrap()
             .eval_int_with_context_mut(&mut context),
         Ok(3)
     );
+    assert_eq!(
+        build_operator_tree("3.3")
+            .unwrap()
+            .eval_int_with_context_mut(&mut context),
+        Err(EvalexprError::ExpectedInt {
+            actual: Value::Float(3.3)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("(,);.")
+            .unwrap()
+            .eval_int_with_context_mut(&mut context),
+        Err(EvalexprError::VariableIdentifierNotFound(".".to_owned()))
+    );
+
+    assert_eq!(build_operator_tree("3").unwrap().eval_number(), Ok(3.0));
+    assert_eq!(
+        build_operator_tree("true").unwrap().eval_number(),
+        Err(EvalexprError::ExpectedNumber {
+            actual: Value::Boolean(true)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("abc").unwrap().eval_number(),
+        Err(EvalexprError::VariableIdentifierNotFound("abc".to_owned()))
+    );
+    assert_eq!(
+        build_operator_tree("3")
+            .unwrap()
+            .eval_number_with_context(&context),
+        Ok(3.0)
+    );
+    assert_eq!(
+        build_operator_tree("true")
+            .unwrap()
+            .eval_number_with_context(&context),
+        Err(EvalexprError::ExpectedNumber {
+            actual: Value::Boolean(true)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("abc")
+            .unwrap()
+            .eval_number_with_context(&context),
+        Err(EvalexprError::VariableIdentifierNotFound("abc".to_owned()))
+    );
     assert_eq!(
         build_operator_tree("3")
             .unwrap()
             .eval_number_with_context_mut(&mut context),
         Ok(3.0)
     );
+    assert_eq!(
+        build_operator_tree("true")
+            .unwrap()
+            .eval_number_with_context_mut(&mut context),
+        Err(EvalexprError::ExpectedNumber {
+            actual: Value::Boolean(true)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("abc")
+            .unwrap()
+            .eval_number_with_context_mut(&mut context),
+        Err(EvalexprError::VariableIdentifierNotFound("abc".to_owned()))
+    );
+
+    assert_eq!(
+        build_operator_tree("true").unwrap().eval_boolean(),
+        Ok(true)
+    );
+    assert_eq!(
+        build_operator_tree("4").unwrap().eval_boolean(),
+        Err(EvalexprError::ExpectedBoolean {
+            actual: Value::Int(4)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("trueee").unwrap().eval_boolean(),
+        Err(EvalexprError::VariableIdentifierNotFound(
+            "trueee".to_owned()
+        ))
+    );
+    assert_eq!(
+        build_operator_tree("true")
+            .unwrap()
+            .eval_boolean_with_context(&context),
+        Ok(true)
+    );
+    assert_eq!(
+        build_operator_tree("4")
+            .unwrap()
+            .eval_boolean_with_context(&context),
+        Err(EvalexprError::ExpectedBoolean {
+            actual: Value::Int(4)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("trueee")
+            .unwrap()
+            .eval_boolean_with_context(&context),
+        Err(EvalexprError::VariableIdentifierNotFound(
+            "trueee".to_owned()
+        ))
+    );
     assert_eq!(
         build_operator_tree("true")
             .unwrap()
             .eval_boolean_with_context_mut(&mut context),
         Ok(true)
     );
+    assert_eq!(
+        build_operator_tree("4")
+            .unwrap()
+            .eval_boolean_with_context_mut(&mut context),
+        Err(EvalexprError::ExpectedBoolean {
+            actual: Value::Int(4)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("trueee")
+            .unwrap()
+            .eval_boolean_with_context_mut(&mut context),
+        Err(EvalexprError::VariableIdentifierNotFound(
+            "trueee".to_owned()
+        ))
+    );
+
+    assert_eq!(
+        build_operator_tree("3,3").unwrap().eval_tuple(),
+        Ok(vec![Value::Int(3), Value::Int(3)])
+    );
+    assert_eq!(
+        build_operator_tree("33").unwrap().eval_tuple(),
+        Err(EvalexprError::ExpectedTuple {
+            actual: Value::Int(33)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("3a3").unwrap().eval_tuple(),
+        Err(EvalexprError::VariableIdentifierNotFound("3a3".to_owned()))
+    );
+    assert_eq!(
+        build_operator_tree("3,3")
+            .unwrap()
+            .eval_tuple_with_context(&context),
+        Ok(vec![Value::Int(3), Value::Int(3)])
+    );
+    assert_eq!(
+        build_operator_tree("33")
+            .unwrap()
+            .eval_tuple_with_context(&context),
+        Err(EvalexprError::ExpectedTuple {
+            actual: Value::Int(33)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("3a3")
+            .unwrap()
+            .eval_tuple_with_context(&context),
+        Err(EvalexprError::VariableIdentifierNotFound("3a3".to_owned()))
+    );
     assert_eq!(
         build_operator_tree("3,3")
             .unwrap()
             .eval_tuple_with_context_mut(&mut context),
         Ok(vec![Value::Int(3), Value::Int(3)])
     );
+    assert_eq!(
+        build_operator_tree("33")
+            .unwrap()
+            .eval_tuple_with_context_mut(&mut context),
+        Err(EvalexprError::ExpectedTuple {
+            actual: Value::Int(33)
+        })
+    );
+    assert_eq!(
+        build_operator_tree("3a3")
+            .unwrap()
+            .eval_tuple_with_context_mut(&mut context),
+        Err(EvalexprError::VariableIdentifierNotFound("3a3".to_owned()))
+    );
+
+    assert_eq!(
+        build_operator_tree("").unwrap().eval_empty(),
+        Ok(EMPTY_VALUE)
+    );
+    assert_eq!(
+        build_operator_tree("()").unwrap().eval_empty(),
+        Ok(EMPTY_VALUE)
+    );
+    assert_eq!(
+        build_operator_tree("(,)").unwrap().eval_empty(),
+        Err(EvalexprError::ExpectedEmpty {
+            actual: Value::Tuple(vec![Value::Empty, Value::Empty])
+        })
+    );
+    assert_eq!(
+        build_operator_tree("xaq").unwrap().eval_empty(),
+        Err(EvalexprError::VariableIdentifierNotFound("xaq".to_owned()))
+    );
+    assert_eq!(
+        build_operator_tree("")
+            .unwrap()
+            .eval_empty_with_context(&context),
+        Ok(EMPTY_VALUE)
+    );
+    assert_eq!(
+        build_operator_tree("()")
+            .unwrap()
+            .eval_empty_with_context(&context),
+        Ok(EMPTY_VALUE)
+    );
+    assert_eq!(
+        build_operator_tree("(,)")
+            .unwrap()
+            .eval_empty_with_context(&context),
+        Err(EvalexprError::ExpectedEmpty {
+            actual: Value::Tuple(vec![Value::Empty, Value::Empty])
+        })
+    );
+    assert_eq!(
+        build_operator_tree("xaq")
+            .unwrap()
+            .eval_empty_with_context(&context),
+        Err(EvalexprError::VariableIdentifierNotFound("xaq".to_owned()))
+    );
     assert_eq!(
         build_operator_tree("")
             .unwrap()
             .eval_empty_with_context_mut(&mut context),
         Ok(EMPTY_VALUE)
     );
+    assert_eq!(
+        build_operator_tree("()")
+            .unwrap()
+            .eval_empty_with_context_mut(&mut context),
+        Ok(EMPTY_VALUE)
+    );
+    assert_eq!(
+        build_operator_tree("(,)")
+            .unwrap()
+            .eval_empty_with_context_mut(&mut context),
+        Err(EvalexprError::ExpectedEmpty {
+            actual: Value::Tuple(vec![Value::Empty, Value::Empty])
+        })
+    );
+    assert_eq!(
+        build_operator_tree("xaq")
+            .unwrap()
+            .eval_empty_with_context_mut(&mut context),
+        Err(EvalexprError::VariableIdentifierNotFound("xaq".to_owned()))
+    );
 }
 
 #[test]