Better argument validation for core methods.

test/list/remove_at.wren

@@ -23,10 +23,5 @@ var f = [1, 2, 3]
 f.removeAt(-1)
 IO.write(f) // expect: [1, 2]
 
-// Out of bounds.
-// TODO: Signal error in better way.
-IO.write([1, 2, 3].removeAt(3)) // expect: null
-IO.write([1, 2, 3].removeAt(-4)) // expect: null
-
 // Return the removed value.
 IO.write([3, 4, 5].removeAt(1)) // expect: 4

test/list/remove_at_index_not_int.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a.removeAt(1.5) // expect runtime error: Index must be an integer.

test/list/remove_at_index_not_num.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a.removeAt("2") // expect runtime error: Index must be a number.

test/list/remove_at_index_too_large.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a.removeAt(4) // expect runtime error: Index out of bounds.

test/list/remove_at_index_too_small.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a.removeAt(-5) // expect runtime error: Index out of bounds.

test/list/subscript.wren

@@ -10,16 +10,3 @@ IO.write(list[-4]) // expect: a
 IO.write(list[-3]) // expect: b
 IO.write(list[-2]) // expect: c
 IO.write(list[-1]) // expect: d
-
-// Handle out of bounds.
-// TODO: Should halt the fiber or raise an error somehow.
-IO.write(list[4])  // expect: null
-IO.write(list[-5]) // expect: null
-
-// Handle wrong argument type.
-// TODO: Should halt the fiber or raise an error somehow.
-IO.write(list[true]) // expect: null
-
-// Handle non-integer index.
-// TODO: Should halt the fiber or raise an error somehow.
-IO.write(list[1.5]) // expect: null

test/list/subscript_not_int.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a[1.5] // expect runtime error: Subscript must be an integer.

test/list/subscript_not_num.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a["2"] // expect runtime error: Subscript must be a number.

test/list/subscript_setter_not_int.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a[1.5] = 1 // expect runtime error: Subscript must be an integer.

test/list/subscript_setter_not_num.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a["2"] = 1 // expect runtime error: Subscript must be a number.

test/list/subscript_setter_too_large.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a[4] = 1 // expect runtime error: Subscript out of bounds.

test/list/subscript_setter_too_small.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a[-5] = 1 // expect runtime error: Subscript out of bounds.

test/list/subscript_too_large.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a[4] // expect runtime error: Subscript out of bounds.

test/list/subscript_too_small.wren

@@ -0,0 +1,2 @@
+var a = [1, 2, 3]
+a[-5] // expect runtime error: Subscript out of bounds.