Project incoming source destinations through tier operations

internal/engine/source_version.go

@@ -53,6 +53,13 @@ type sourceVersionState struct {
 	diagnostics    []Diagnostic
 }
 
+func (state *sourceVersionState) evidenceSince(start int) []*sourceVersionEvidence {
+	if state == nil {
+		return nil
+	}
+	return state.evidence[start:]
+}
+
 func sourceInfosWithVersionEvidence(sources []SourceInfo, evidence []*sourceVersionEvidence, secrets map[string]bool, conservative bool) []SourceInfo {
 	result := cloneSourceInfos(sources)
 	if len(evidence) == 0 {