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 * Fix outdated slice syntax in docs.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, 227 deletions

diff --git a/test/cases/while.zig b/test/cases/while.zig
deleted file mode 100644
index f774e0ec6b..0000000000
--- a/test/cases/while.zig
+++ /dev/null
@@ -1,227 +0,0 @@
-const assert = @import("std").debug.assert;
-
-test "while loop" {
-    var i: i32 = 0;
-    while (i < 4) {
-        i += 1;
-    }
-    assert(i == 4);
-    assert(whileLoop1() == 1);
-}
-fn whileLoop1() i32 {
-    return whileLoop2();
-}
-fn whileLoop2() i32 {
-    while (true) {
-        return 1;
-    }
-}
-test "static eval while" {
-    assert(static_eval_while_number == 1);
-}
-const static_eval_while_number = staticWhileLoop1();
-fn staticWhileLoop1() i32 {
-    return whileLoop2();
-}
-fn staticWhileLoop2() i32 {
-    while (true) {
-        return 1;
-    }
-}
-
-test "continue and break" {
-    runContinueAndBreakTest();
-    assert(continue_and_break_counter == 8);
-}
-var continue_and_break_counter: i32 = 0;
-fn runContinueAndBreakTest() void {
-    var i: i32 = 0;
-    while (true) {
-        continue_and_break_counter += 2;
-        i += 1;
-        if (i < 4) {
-            continue;
-        }
-        break;
-    }
-    assert(i == 4);
-}
-
-test "return with implicit cast from while loop" {
-    returnWithImplicitCastFromWhileLoopTest() catch unreachable;
-}
-fn returnWithImplicitCastFromWhileLoopTest() anyerror!void {
-    while (true) {
-        return;
-    }
-}
-
-test "while with continue expression" {
-    var sum: i32 = 0;
-    {
-        var i: i32 = 0;
-        while (i < 10) : (i += 1) {
-            if (i == 5) continue;
-            sum += i;
-        }
-    }
-    assert(sum == 40);
-}
-
-test "while with else" {
-    var sum: i32 = 0;
-    var i: i32 = 0;
-    var got_else: i32 = 0;
-    while (i < 10) : (i += 1) {
-        sum += 1;
-    } else {
-        got_else += 1;
-    }
-    assert(sum == 10);
-    assert(got_else == 1);
-}
-
-test "while with optional as condition" {
-    numbers_left = 10;
-    var sum: i32 = 0;
-    while (getNumberOrNull()) |value| {
-        sum += value;
-    }
-    assert(sum == 45);
-}
-
-test "while with optional as condition with else" {
-    numbers_left = 10;
-    var sum: i32 = 0;
-    var got_else: i32 = 0;
-    while (getNumberOrNull()) |value| {
-        sum += value;
-        assert(got_else == 0);
-    } else {
-        got_else += 1;
-    }
-    assert(sum == 45);
-    assert(got_else == 1);
-}
-
-test "while with error union condition" {
-    numbers_left = 10;
-    var sum: i32 = 0;
-    var got_else: i32 = 0;
-    while (getNumberOrErr()) |value| {
-        sum += value;
-    } else |err| {
-        assert(err == error.OutOfNumbers);
-        got_else += 1;
-    }
-    assert(sum == 45);
-    assert(got_else == 1);
-}
-
-var numbers_left: i32 = undefined;
-fn getNumberOrErr() anyerror!i32 {
-    return if (numbers_left == 0) error.OutOfNumbers else x: {
-        numbers_left -= 1;
-        break :x numbers_left;
-    };
-}
-fn getNumberOrNull() ?i32 {
-    return if (numbers_left == 0) null else x: {
-        numbers_left -= 1;
-        break :x numbers_left;
-    };
-}
-
-test "while on optional with else result follow else prong" {
-    const result = while (returnNull()) |value| {
-        break value;
-    } else
-        i32(2);
-    assert(result == 2);
-}
-
-test "while on optional with else result follow break prong" {
-    const result = while (returnOptional(10)) |value| {
-        break value;
-    } else
-        i32(2);
-    assert(result == 10);
-}
-
-test "while on error union with else result follow else prong" {
-    const result = while (returnError()) |value| {
-        break value;
-    } else |err|
-        i32(2);
-    assert(result == 2);
-}
-
-test "while on error union with else result follow break prong" {
-    const result = while (returnSuccess(10)) |value| {
-        break value;
-    } else |err|
-        i32(2);
-    assert(result == 10);
-}
-
-test "while on bool with else result follow else prong" {
-    const result = while (returnFalse()) {
-        break i32(10);
-    } else
-        i32(2);
-    assert(result == 2);
-}
-
-test "while on bool with else result follow break prong" {
-    const result = while (returnTrue()) {
-        break i32(10);
-    } else
-        i32(2);
-    assert(result == 10);
-}
-
-test "break from outer while loop" {
-    testBreakOuter();
-    comptime testBreakOuter();
-}
-
-fn testBreakOuter() void {
-    outer: while (true) {
-        while (true) {
-            break :outer;
-        }
-    }
-}
-
-test "continue outer while loop" {
-    testContinueOuter();
-    comptime testContinueOuter();
-}
-
-fn testContinueOuter() void {
-    var i: usize = 0;
-    outer: while (i < 10) : (i += 1) {
-        while (true) {
-            continue :outer;
-        }
-    }
-}
-
-fn returnNull() ?i32 {
-    return null;
-}
-fn returnOptional(x: i32) ?i32 {
-    return x;
-}
-fn returnError() anyerror!i32 {
-    return error.YouWantedAnError;
-}
-fn returnSuccess(x: i32) anyerror!i32 {
-    return x;
-}
-fn returnFalse() bool {
-    return false;
-}
-fn returnTrue() bool {
-    return true;
-}