coverage: Make BcbCounter module-private

Author: Zalathar

compiler/rustc_mir_transform/src/coverage/counters.rs

@@ -13,13 +13,13 @@ use crate::coverage::graph::{BasicCoverageBlock, CoverageGraph, TraverseCoverage
 /// The coverage counter or counter expression associated with a particular
 /// BCB node or BCB edge.
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
-pub(super) enum BcbCounter {
+enum BcbCounter {
     Counter { id: CounterId },
     Expression { id: ExpressionId },
 }
 
 impl BcbCounter {
-    pub(super) fn as_term(&self) -> CovTerm {
+    fn as_term(&self) -> CovTerm {
         match *self {
             BcbCounter::Counter { id, .. } => CovTerm::Counter(id),
             BcbCounter::Expression { id, .. } => CovTerm::Expression(id),
@@ -218,8 +218,8 @@ impl CoverageCounters {
         }
     }
 
-    pub(super) fn bcb_counter(&self, bcb: BasicCoverageBlock) -> Option<BcbCounter> {
-        self.bcb_counters[bcb]
+    pub(super) fn term_for_bcb(&self, bcb: BasicCoverageBlock) -> Option<CovTerm> {
+        self.bcb_counters[bcb].map(|counter| counter.as_term())
     }
 
     /// Returns an iterator over all the nodes/edges in the coverage graph that

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -153,12 +153,8 @@ fn create_mappings<'tcx>(
         &source_file.name.for_scope(tcx.sess, RemapPathScopeComponents::MACRO).to_string_lossy(),
     );
 
-    let term_for_bcb = |bcb| {
-        coverage_counters
-            .bcb_counter(bcb)
-            .expect("all BCBs with spans were given counters")
-            .as_term()
-    };
+    let term_for_bcb =
+        |bcb| coverage_counters.term_for_bcb(bcb).expect("all BCBs with spans were given counters");
     let region_for_span = |span: Span| make_source_region(source_map, file_name, span, body_span);
 
     // Fully destructure the mappings struct to make sure we don't miss any kinds.