feat(tvix/eval): track span of first force in a thunk blackhole r/6025

This is step 1 towards being able to use all 4 spans that we know when
dealing with infinite recursion. It tracks the span at which the
force of a thunk was first requested when constructing a blackhole, so
that we can highlight the spans of the first and second forces.

These are actually the least relevant spans, but the easiest to put in
place, more coming soon.

Change-Id: I4c7e82f6211b98756439d4148a4191457cc46807
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8269
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 3 insertions, 2 deletions

diff --git a/tvix/eval/src/value/mod.rs b/tvix/eval/src/value/mod.rs
index f57cfda5ee..77d40b0e39 100644
--- a/tvix/eval/src/value/mod.rs
+++ b/tvix/eval/src/value/mod.rs
@@ -22,6 +22,7 @@ mod thunk;
 
 use crate::errors::ErrorKind;
 use crate::opcode::StackIdx;
+use crate::spans::LightSpan;
 use crate::vm::generators::{self, GenCo};
 use crate::AddContext;
 pub use attrs::NixAttrs;
@@ -611,9 +612,9 @@ impl Value {
     }
 
     // TODO(amjoseph): de-asyncify this (when called directly by the VM)
-    pub async fn force(self, co: GenCo) -> Result<Value, ErrorKind> {
+    pub async fn force(self, co: GenCo, span: LightSpan) -> Result<Value, ErrorKind> {
         if let Value::Thunk(thunk) = self {
-            return thunk.force(co).await;
+            return thunk.force(co, span).await;
         }
 
         Ok(self)