internal/core/adt: do not hasNonCycle in one case

With the structural cycle detection rework, this no
longer seems necessary. As it is safer to be
non-permissive, we do not set this flag. We leave
it in, however, to quickly be able to set it if an
issue bisects to this change.

Issue #3731
Issue #3634

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: Ie411bf9eca647e675e5a74b12245175e7aa0909c
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1209385
Reviewed-by: Matthew Sackman <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

Author: mpvl

internal/core/adt/conjunct.go

@@ -110,6 +110,13 @@ func (n *nodeContext) scheduleConjunct(c Conjunct, id CloseInfo) {
 			//		}
 			// panic("inconsistent state: nodes differ")
 		}
+		// TODO: consider setting this as a safety measure.
+		// if c.CloseInfo.CycleType > id.CycleType {
+		// 	id.CycleType = c.CloseInfo.CycleType
+		// }
+		// if c.CloseInfo.IsCyclic {
+		// 	id.IsCyclic = true
+		// }
 	default:
 
 		// In this case, the conjunct is inserted as the result of an expansion

internal/core/adt/unify.go

@@ -764,7 +764,9 @@ func (v *Vertex) lookup(c *OpContext, pos token.Pos, f Feature, flags combinedFl
 
 		// A lookup counts as new structure. See the commend in Section
 		// "Lookups in inline cycles" in cycle.go.
-		state.hasNonCycle = true
+		// TODO: this seems no longer necessary and setting this will cause some
+		// hangs. Investigate.
+		// state.hasNonCycle = true
 
 		// TODO: ideally this should not be run at this point. Consider under
 		// which circumstances this is still necessary, and at least ensure