Bug fixes for or-patterns in match statement coverage

Author: ranger-ross

compiler/rustc_mir_build/src/build/coverageinfo.rs

@@ -46,13 +46,12 @@ struct NotInfo {
 pub(crate) struct MatchArm {
     pub(crate) source_info: SourceInfo,
     pub(crate) sub_branches: Vec<MatchArmSubBranch>,
-    pub(crate) arm_block: BasicBlock,
 }
 
 #[derive(Debug)]
 pub(crate) struct MatchArmSubBranch {
     pub(crate) source_info: SourceInfo,
-    pub(crate) start_block: Option<BasicBlock>,
+    pub(crate) block: BasicBlock,
 }
 
 #[derive(Default)]
@@ -193,24 +192,24 @@ impl CoverageInfoBuilder {
 
         let branch_arms = arms
             .iter()
-            .flat_map(|MatchArm { source_info, sub_branches, arm_block }| {
-                let arm_taken_marker =
-                    self.markers.inject_block_marker(cfg, *source_info, *arm_block);
-                let branch_arms = sub_branches
+            .flat_map(|MatchArm { source_info, sub_branches }| {
+                sub_branches
                     .iter()
-                    .filter_map(|sub_branch| {
-                        let Some(block) = sub_branch.start_block else { return None };
-                        let marker =
+                    .map(|sub_branch| {
+                        let block = sub_branch.block;
+
+                        let pre_guard_marker =
                             self.markers.inject_block_marker(cfg, sub_branch.source_info, block);
-                        Some(BranchArm {
+                        let arm_taken_marker =
+                            self.markers.inject_block_marker(cfg, *source_info, block);
+
+                        BranchArm {
                             span: sub_branch.source_info.span,
-                            pre_guard_marker: marker,
+                            pre_guard_marker,
                             arm_taken_marker,
-                        })
+                        }
                     })
-                    .collect::<Vec<_>>();
-
-                branch_arms
+                    .collect::<Vec<_>>()
             })
             .collect::<Vec<_>>();
 

compiler/rustc_mir_build/src/build/matches/mod.rs

@@ -458,7 +458,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         .iter()
                         .map(|b| coverageinfo::MatchArmSubBranch {
                             source_info: this.source_info(b.span),
-                            start_block: b.start_block,
+                            block: b.success_block,
                         })
                         .collect();
 
@@ -475,7 +475,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         coverage_match_arms.push(coverageinfo::MatchArm {
                             source_info: this.source_info(arm.pattern.span),
                             sub_branches,
-                            arm_block,
                         })
                     }
 
@@ -1397,8 +1396,6 @@ pub(crate) struct ArmHasGuard(pub(crate) bool);
 #[derive(Debug)]
 struct MatchTreeSubBranch<'tcx> {
     span: Span,
-    /// The first block in this sub branch.
-    start_block: Option<BasicBlock>,
     /// The block that is branched to if the corresponding subpattern matches.
     success_block: BasicBlock,
     /// The block to branch to if this arm had a guard and the guard fails.
@@ -1449,7 +1446,6 @@ impl<'tcx> MatchTreeSubBranch<'tcx> {
         debug_assert!(candidate.match_pairs.is_empty());
         MatchTreeSubBranch {
             span: candidate.extra_data.span,
-            start_block: candidate.false_edge_start_block,
             success_block: candidate.pre_binding_block.unwrap(),
             otherwise_block: candidate.otherwise_block.unwrap(),
             bindings: parent_data