backport copy elision changes

This commit contains everything from the copy-elision-2
branch that does not have to do with copy elision directly,
but is generally useful for master branch.

 * All const values know their parents, when applicable, not
   just structs and unions.
 * Null pointers in const values are represented explicitly,
   rather than as a HardCodedAddr value of 0.
 * Rename "maybe" to "optional" in various code locations.
 * Separate DeclVarSrc and DeclVarGen
 * Separate PtrCastSrc and PtrCastGen
 * Separate CmpxchgSrc and CmpxchgGen
 * Represent optional error set as an integer, using the 0 value.
   In a const value, it uses nullptr.
 * Introduce type_has_one_possible_value and use it where applicable.
 * Fix debug builds not setting memory to 0xaa when storing
   undefined.
 * Separate the type of a variable from the const value of a variable.
 * Use copy_const_val where appropriate.
 * Rearrange structs to pack data more efficiently.
 * Move test/cases/* to test/behavior/*
 * Use `std.debug.assertOrPanic` in behavior tests instead of
   `std.debug.assert`.
 * Fix outdated slice syntax in docs.

1 files changed, 0 insertions, 40 deletions

diff --git a/test/cases/slice.zig b/test/cases/slice.zig
deleted file mode 100644
index b4b43bdd19..0000000000
--- a/test/cases/slice.zig
+++ /dev/null
@@ -1,40 +0,0 @@
-const assert = @import("std").debug.assert;
-const mem = @import("std").mem;
-
-const x = @intToPtr([*]i32, 0x1000)[0..0x500];
-const y = x[0x100..];
-test "compile time slice of pointer to hard coded address" {
-    assert(@ptrToInt(x.ptr) == 0x1000);
-    assert(x.len == 0x500);
-
-    assert(@ptrToInt(y.ptr) == 0x1100);
-    assert(y.len == 0x400);
-}
-
-test "slice child property" {
-    var array: [5]i32 = undefined;
-    var slice = array[0..];
-    assert(@typeOf(slice).Child == i32);
-}
-
-test "runtime safety lets us slice from len..len" {
-    var an_array = []u8{
-        1,
-        2,
-        3,
-    };
-    assert(mem.eql(u8, sliceFromLenToLen(an_array[0..], 3, 3), ""));
-}
-
-fn sliceFromLenToLen(a_slice: []u8, start: usize, end: usize) []u8 {
-    return a_slice[start..end];
-}
-
-test "implicitly cast array of size 0 to slice" {
-    var msg = []u8{};
-    assertLenIsZero(msg);
-}
-
-fn assertLenIsZero(msg: []const u8) void {
-    assert(msg.len == 0);
-}