diff --git a/builtins.go b/builtins.go
index 44dc304..33719b6 100644
--- a/builtins.go
+++ b/builtins.go
@@ -248,7 +248,7 @@ func builtinToString(e *evaluator, xp potentialValue) (value, error) {
 }
 
 func builtinMakeArray(e *evaluator, szp potentialValue, funcp potentialValue) (value, error) {
-	sz, err := e.evaluateNumber(szp)
+	sz, err := e.evaluateInt(szp)
 	if err != nil {
 		return nil, err
 	}
@@ -256,9 +256,8 @@ func builtinMakeArray(e *evaluator, szp potentialValue, funcp potentialValue) (v
 	if err != nil {
 		return nil, err
 	}
-	num := int(sz.value)
 	var elems []potentialValue
-	for i := 0; i < num; i++ {
+	for i := 0; i < sz; i++ {
 		elem := fun.call(args(&readyValue{intToValue(i)}))
 		elems = append(elems, elem)
 	}
@@ -274,7 +273,7 @@ func builtinFlatMap(e *evaluator, funcp potentialValue, arrp potentialValue) (va
 	if err != nil {
 		return nil, err
 	}
-	num := int(arr.length())
+	num := arr.length()
 	// Start with capacity of the original array.
 	// This may spare us a few reallocations.
 	// TODO(sbarzowski) verify that it actually helps
@@ -300,7 +299,7 @@ func builtinFilter(e *evaluator, funcp potentialValue, arrp potentialValue) (val
 	if err != nil {
 		return nil, err
 	}
-	num := int(arr.length())
+	num := arr.length()
 	// Start with capacity of the original array.
 	// This may spare us a few reallocations.
 	// TODO(sbarzowski) verify that it actually helps
@@ -479,17 +478,15 @@ var builtinExponent = liftNumeric(func(f float64) float64 {
 
 func liftBitwise(f func(int64, int64) int64) func(*evaluator, potentialValue, potentialValue) (value, error) {
 	return func(e *evaluator, xp, yp potentialValue) (value, error) {
-		x, err := e.evaluateNumber(xp)
+		x, err := e.evaluateInt64(xp)
 		if err != nil {
 			return nil, err
 		}
-		y, err := e.evaluateNumber(yp)
+		y, err := e.evaluateInt64(yp)
 		if err != nil {
 			return nil, err
 		}
-		xInt := int64(x.value)
-		yInt := int64(y.value)
-		return makeDoubleCheck(e, float64(f(xInt, yInt)))
+		return makeDoubleCheck(e, float64(f(x, y)))
 	}
 }
 
diff --git a/evaluator.go b/evaluator.go
index 43e80a4..5409a85 100644
--- a/evaluator.go
+++ b/evaluator.go
@@ -83,6 +83,50 @@ func (e *evaluator) evaluateNumber(pv potentialValue) (*valueNumber, error) {
 	return e.getNumber(v)
 }
 
+func (e *evaluator) getInt(val value) (int, error) {
+	num, err := e.getNumber(val)
+	if err != nil {
+		return 0, err
+	}
+	// We conservatively convert ot int32, so that it can be machine-sized int
+	// on any machine. And it's used only for indexing anyway.
+	intNum := int(int32(num.value))
+	if float64(intNum) != num.value {
+		return 0, e.Error(fmt.Sprintf("Expected an integer, but got %v", num.value))
+	}
+	return intNum, nil
+}
+
+func (e *evaluator) evaluateInt(pv potentialValue) (int, error) {
+	v, err := e.evaluate(pv)
+	if err != nil {
+		return 0, err
+	}
+	return e.getInt(v)
+}
+
+func (e *evaluator) getInt64(val value) (int64, error) {
+	num, err := e.getNumber(val)
+	if err != nil {
+		return 0, err
+	}
+	// We conservatively convert ot int32, so that it can be machine-sized int
+	// on any machine. And it's used only for indexing anyway.
+	intNum := int64(num.value)
+	if float64(intNum) != num.value {
+		return 0, e.Error(fmt.Sprintf("Expected an integer, but got %v", num.value))
+	}
+	return intNum, nil
+}
+
+func (e *evaluator) evaluateInt64(pv potentialValue) (int64, error) {
+	v, err := e.evaluate(pv)
+	if err != nil {
+		return 0, err
+	}
+	return e.getInt64(v)
+}
+
 func (e *evaluator) getString(val value) (*valueString, error) {
 	switch v := val.(type) {
 	case *valueString:
diff --git a/testdata/bitwise_and3.golden b/testdata/bitwise_and3.golden
index 573541a..836e54d 100644
--- a/testdata/bitwise_and3.golden
+++ b/testdata/bitwise_and3.golden
@@ -1 +1,10 @@
-0
+RUNTIME ERROR: Expected an integer, but got 1e+30
+-------------------------------------------------
+	testdata/bitwise_and3:1:1-10	$
+
+1e30 & 42
+
+-------------------------------------------------
+	During evaluation	
+
+
diff --git a/testdata/std.makeArray_noninteger.golden b/testdata/std.makeArray_noninteger.golden
new file mode 100644
index 0000000..15485d3
--- /dev/null
+++ b/testdata/std.makeArray_noninteger.golden
@@ -0,0 +1,8 @@
+RUNTIME ERROR: Expected an integer, but got 2.5
+-------------------------------------------------
+	<builtin>	builtin function <makeArray>
+
+-------------------------------------------------
+	During evaluation	
+
+
diff --git a/testdata/std.makeArray_noninteger.jsonnet b/testdata/std.makeArray_noninteger.jsonnet
new file mode 100644
index 0000000..c046e67
--- /dev/null
+++ b/testdata/std.makeArray_noninteger.jsonnet
@@ -0,0 +1 @@
+std.makeArray(2.5, function(i) i)
diff --git a/testdata/std.makeArray_noninteger_big.golden b/testdata/std.makeArray_noninteger_big.golden
new file mode 100644
index 0000000..974142d
--- /dev/null
+++ b/testdata/std.makeArray_noninteger_big.golden
@@ -0,0 +1,8 @@
+RUNTIME ERROR: Expected an integer, but got 1e+100
+-------------------------------------------------
+	<builtin>	builtin function <makeArray>
+
+-------------------------------------------------
+	During evaluation	
+
+
diff --git a/testdata/std.makeArray_noninteger_big.jsonnet b/testdata/std.makeArray_noninteger_big.jsonnet
new file mode 100644
index 0000000..9bd2ba3
--- /dev/null
+++ b/testdata/std.makeArray_noninteger_big.jsonnet
@@ -0,0 +1 @@
+std.makeArray(1e100, error "shouldn't happen")