fix interop and indexing oversights

examples/programs/array_const_size_error/main.bro

@@ -0,0 +1,5 @@
+main func() i32 {
+	n usize = 4
+	items [n]mut i32 = undefined
+	return 0
+}

examples/programs/index_int_constraint_error/main.bro

@@ -0,0 +1,6 @@
+main func() i32 {
+	items [3]mut i32 = undefined
+	i int = 1
+	items[i] = 42
+	return 0
+}

examples/programs/index_signed_error/main.bro

@@ -0,0 +1,6 @@
+main func() i32 {
+	items [3]mut i32 = undefined
+	i i32 = 1
+	items[i] = 42
+	return 0
+}

examples/programs/milestone_24/main.bro

@@ -0,0 +1,93 @@
+CAP :: 4
+LEN :: CAP + 1
+
+Kind :: enum {
+	circle
+	square
+	triangle
+}
+
+take_c_int func(value c_int) c_int {
+	return value
+}
+
+take_c_uchar func(value c_uchar) c_uchar {
+	return value
+}
+
+take_c_float func(value c_float) c_float {
+	return value
+}
+
+take_c_double func(value c_double) c_double {
+	return value
+}
+
+take_c_string func(value ?*c_char) i32 {
+	_ = value
+	return 0
+}
+
+next_kind func(k Kind) Kind {
+	return match k {
+		.circle:   .square
+		.square:   .triangle
+		.triangle: .circle
+	}
+}
+
+score_for func(k Kind) i32 {
+	score :: {
+		yield match k {
+			.circle:   1
+			.square:   2
+			.triangle: 3
+		}
+	}
+	return score
+}
+
+main func() i32 {
+	items [LEN]mut i32 = undefined
+	items[0] = 10
+	items[1] = 20
+
+	idx u8 = 2
+	items[idx] = items[0] + items[1]
+	if (items[2] != 30) return 1
+
+	native_i i32 = 12
+	if (take_c_int(native_i) != 12) return 2
+
+	native_u u8 = 7
+	if (take_c_uchar(native_u) != 7) return 3
+
+	native_f f32 = 3.25
+	cf :: take_c_float(native_f)
+	if (cf < 3.0 or cf > 4.0) return 4
+	if (cf == 0.0) return 5
+
+	native_d f64 = 5.0
+	cd :: take_c_double(native_d)
+	if (cd != 5.0) return 6
+
+	as_i32 :: i32(cf)
+	if (as_i32 != 3) return 7
+	as_float :: f32(native_i)
+	if (as_float < 11.5 or as_float > 12.5) return 8
+	as_c_float :: c_float(as_i32)
+	if (as_c_float != 3.0) return 9
+
+	kind :: next_kind(.circle)
+	if (kind != .square) return 10
+	if (score_for(kind) != 2) return 11
+
+	label :: match kind {
+		.circle:   "circle"
+		.square:   "square"
+		.triangle: "triangle"
+	}
+	if (take_c_string(label) != 0) return 12
+
+	return 0
+}

examples/programs/scalar_cast_error/main.bro

@@ -0,0 +1,5 @@
+main func() i32 {
+	flag bool = true
+	value :: i32(flag)
+	return value
+}