(> 1e6e3fb)remove useless &mut of extracted_mappings

Author: zhuyunxing

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -103,7 +103,7 @@ fn instrument_function_for_coverage<'tcx>(tcx: TyCtxt<'tcx>, mir_body: &mut mir:
         mir_body,
         tcx,
         &hir_info,
-        &mut extracted_mappings,
+        &extracted_mappings,
         &basic_coverage_blocks,
         &mut coverage_counters,
     );
@@ -148,7 +148,7 @@ fn create_mappings<'tcx>(
     mir_body: &mut mir::Body<'tcx>,
     tcx: TyCtxt<'tcx>,
     hir_info: &ExtractedHirInfo,
-    extracted_mappings: &mut ExtractedMappings,
+    extracted_mappings: &ExtractedMappings,
     basic_coverage_blocks: &CoverageGraph,
     coverage_counters: &mut CoverageCounters,
 ) -> Vec<Mapping> {