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 * Fix outdated slice syntax in docs.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, 44 deletions

diff --git a/test/cases/pointers.zig b/test/cases/pointers.zig
deleted file mode 100644
index 47afb60a2e..0000000000
--- a/test/cases/pointers.zig
+++ /dev/null
@@ -1,44 +0,0 @@
-const std = @import("std");
-const assert = std.debug.assert;
-
-test "dereference pointer" {
-    comptime testDerefPtr();
-    testDerefPtr();
-}
-
-fn testDerefPtr() void {
-    var x: i32 = 1234;
-    var y = &x;
-    y.* += 1;
-    assert(x == 1235);
-}
-
-test "pointer arithmetic" {
-    var ptr = c"abcd";
-
-    assert(ptr[0] == 'a');
-    ptr += 1;
-    assert(ptr[0] == 'b');
-    ptr += 1;
-    assert(ptr[0] == 'c');
-    ptr += 1;
-    assert(ptr[0] == 'd');
-    ptr += 1;
-    assert(ptr[0] == 0);
-    ptr -= 1;
-    assert(ptr[0] == 'd');
-    ptr -= 1;
-    assert(ptr[0] == 'c');
-    ptr -= 1;
-    assert(ptr[0] == 'b');
-    ptr -= 1;
-    assert(ptr[0] == 'a');
-}
-
-test "double pointer parsing" {
-    comptime assert(PtrOf(PtrOf(i32)) == **i32);
-}
-
-fn PtrOf(comptime T: type) type {
-    return *T;
-}