From 22184435c24aee72bdd6e7f57ea25ff043ff49e3 Mon Sep 17 00:00:00 2001 From: Thomas Lively Date: Tue, 3 Nov 2026 10:57:01 -0800 Subject: [PATCH] [spec] Add exactness variables for principal types Enrich the principal types grammar in the appendix with exactness type variables (\alpha_{exact}) and exact type uses so that instructions like ref.get_desc that preserve exactness across concrete heap types have principal type schemes. --- document/core/appendix/properties.rst | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/document/core/appendix/properties.rst b/document/core/appendix/properties.rst index b731592d3..aa250387c 100644 --- a/document/core/appendix/properties.rst +++ b/document/core/appendix/properties.rst @@ -1472,6 +1472,10 @@ Technically, the :ref:`syntax ` of :ref:`heap `, : \begin{array}{llll} \production{nullability} & \X{null} &::=& \NULL^? ~|~ \alpha_{\X{null}} \\ + \production{exactness} & \X{exact} &::=& + \EXACT^? ~|~ \alpha_{\X{exact}} \\ + \production{exact type use} & \exacttypeuse &::=& + \X{exact}~\typeuse \\ \production{heap type} & \heaptype &::=& \dots ~|~ \alpha_{\heaptype} \\ \production{reference type} & \reftype &::=&