Add a test for a bug I found while writing a script

This bug is complicated, but it is caused when an element from an array
is passed as a parameter, and then a later parameter is named the same
as the array whose element was passed in.

I still don't know how to solve it, but this test fails properly while
the bug still exists.

Signed-off-by: Gavin Howard <[email protected]>

manuals/development.md

@@ -2496,6 +2496,13 @@ array.bc
 
 :   Tests arrays even harder than the arrays standard test.
 
+array2.bc
+
+:   Implements a test where an array element is passed as a parameter to a
+    function, and then another array is passed to a later parameter that is
+    named the same as the first array. This was added because of a bug found
+    while writing a script in bc.
+
 atan.bc
 
 :   Tests arctangent even harder than the arctangent standard test.

tests/bc/scripts/all.txt

@@ -5,6 +5,7 @@ add.bc
 print.bc
 parse.bc
 array.bc
+array2.bc
 atan.bc
 bessel.bc
 functions.bc

tests/bc/scripts/array2.bc

@@ -0,0 +1,20 @@
+#! /usr/bin/bc -q
+
+define z(x, a[]) {
+	return x + a[1]
+}
+
+define y(x, b[]) {
+	return x + b[1]
+}
+
+a[0] = 5
+a[1] = 6
+
+b[0] = 8
+b[1] = 7
+
+z(a[0], b[])
+y(b[0], a[])
+
+halt

tests/bc/scripts/array2.txt

@@ -0,0 +1,2 @@
+12
+14