From 78cef0cedcb01cfe7fc7e41d2a1d1c5beeab36ec Mon Sep 17 00:00:00 2001 From: Will Dietz Date: Tue, 7 Mar 2023 08:39:28 -0600 Subject: [PATCH] Clarify language about reference uses being above their targets. --- spec.md | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/spec.md b/spec.md index 118f6dc8..04e0b2d8 100644 --- a/spec.md +++ b/spec.md @@ -645,9 +645,10 @@ internally, as described in this section. Input probe references are allowed on internal modules, but they should be used with care because they make it possible to express invalid reference paths. -When probe references are resolved they must target a single element at or -below the resolution point. Support for other scenarios are allowed as -determined by the implementation. +When probe references are used to access the underlying data (e.g., with a +`read`{.firrtl} or `force`{.firrtl}), they must target a statically known +element at or below the point of that use. Support for other scenarios are +allowed as determined by the implementation. Input references are not allowed on public-facing modules: e.g., the top module and external modules.