!! (WIP) track the enclosing ! expression

Author: Zalathar

compiler/rustc_mir_build/src/build/coverageinfo.rs

@@ -2,6 +2,7 @@ use rustc_middle::hir;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::coverage::{BlockMarkerId, BranchSpan, CoverageKind};
 use rustc_middle::mir::{self, BasicBlock, SourceInfo, Statement, StatementKind};
+use rustc_middle::thir::Expr;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{ExpnKind, Span, DUMMY_SP};
@@ -151,6 +152,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     pub(crate) fn coverage_add_branch(
         &mut self,
         cond_source_info: SourceInfo,
+        enclosing_not_expr: Option<&Expr<'tcx>>,
         then_blk: &mut BasicBlock,
         else_blk: &mut BasicBlock,
     ) {
@@ -174,13 +176,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             id
         };
 
-        let true_marker = inject_branch_marker(then_blk);
-        let false_marker = inject_branch_marker(else_blk);
+        let mut span = cond_source_info.span;
+        let mut true_marker = inject_branch_marker(then_blk);
+        let mut false_marker = inject_branch_marker(else_blk);
 
-        hir_info_builder.branch_spans.push(BranchSpan {
-            span: cond_source_info.span,
-            true_marker,
-            false_marker,
-        });
+        if let Some(enclosing_not_expr) = enclosing_not_expr {
+            span = enclosing_not_expr.span;
+            std::mem::swap(&mut true_marker, &mut false_marker);
+        }
+
+        hir_info_builder.branch_spans.push(BranchSpan { span, true_marker, false_marker });
     }
 }

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

@@ -44,6 +44,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         self.then_else_break_inner(
             block,
             expr,
+            None,
             temp_scope_override,
             break_scope,
             variable_source_info,
@@ -54,6 +55,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         &mut self,
         mut block: BasicBlock,
         expr: &Expr<'tcx>,
+        enclosing_not_expr: Option<&Expr<'tcx>>, // Only used by coverage instrumentation
         temp_scope_override: Option<region::Scope>,
         break_scope: region::Scope,
         variable_source_info: SourceInfo,
@@ -107,9 +109,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let local_scope = this.local_scope();
                 let (success_block, failure_block) =
                     this.in_if_then_scope(local_scope, expr_span, |this| {
-                        this.then_else_break(
+                        this.then_else_break_inner(
                             block,
                             &this.thir[arg],
+                            Some(expr),
                             temp_scope_override,
                             local_scope,
                             variable_source_info,
@@ -121,9 +124,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             ExprKind::Scope { region_scope, lint_level, value } => {
                 let region_scope = (region_scope, this.source_info(expr_span));
                 this.in_scope(region_scope, lint_level, |this| {
-                    this.then_else_break(
+                    this.then_else_break_inner(
                         block,
                         &this.thir[value],
+                        enclosing_not_expr,
                         temp_scope_override,
                         break_scope,
                         variable_source_info,
@@ -162,7 +166,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 if let Some(coverage) = &this.coverage
                     && coverage.branch_coverage_enabled
                 {
-                    this.coverage_add_branch(source_info, &mut then_block, &mut else_block);
+                    this.coverage_add_branch(
+                        source_info,
+                        enclosing_not_expr,
+                        &mut then_block,
+                        &mut else_block,
+                    );
                 }
 
                 this.cfg.terminate(block, source_info, term);