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 * Fix outdated slice syntax in docs.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, 4 insertions, 4 deletions

diff --git a/src/ast_render.cpp b/src/ast_render.cpp
index f7eb646e16..994ba5f5b1 100644
--- a/src/ast_render.cpp
+++ b/src/ast_render.cpp
@@ -233,8 +233,8 @@ static const char *node_type_str(NodeType node_type) {
             return "ErrorType";
         case NodeTypeIfErrorExpr:
             return "IfErrorExpr";
-        case NodeTypeTestExpr:
-            return "TestExpr";
+        case NodeTypeIfOptional:
+            return "IfOptional";
         case NodeTypeErrorSetDecl:
             return "ErrorSetDecl";
         case NodeTypeCancel:
@@ -387,7 +387,7 @@ static bool statement_terminates_without_semicolon(AstNode *node) {
             if (node->data.if_err_expr.else_node)
                 return statement_terminates_without_semicolon(node->data.if_err_expr.else_node);
             return node->data.if_err_expr.then_node->type == NodeTypeBlock;
-        case NodeTypeTestExpr:
+        case NodeTypeIfOptional:
             if (node->data.test_expr.else_node)
                 return statement_terminates_without_semicolon(node->data.test_expr.else_node);
             return node->data.test_expr.then_node->type == NodeTypeBlock;
@@ -974,7 +974,7 @@ static void render_node_extra(AstRender *ar, AstNode *node, bool grouped) {
                 }
                 break;
             }
-        case NodeTypeTestExpr:
+        case NodeTypeIfOptional:
             {
                 fprintf(ar->f, "if (");
                 render_node_grouped(ar, node->data.test_expr.target_node);