factor out the rvalue lifetime rule

remove region_scope_tree from RegionCtxt

Apply suggestions from code review

Co-authored-by: Niko Matsakis <niko@alum.mit.edu>

6 files changed, 30 insertions, 16 deletions

diff --git a/compiler/rustc_mir_build/src/build/block.rs b/compiler/rustc_mir_build/src/build/block.rs
index a83328c0cab..e8b939fb51d 100644
--- a/compiler/rustc_mir_build/src/build/block.rs
+++ b/compiler/rustc_mir_build/src/build/block.rs
@@ -108,7 +108,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     let_scope_stack.push(remainder_scope);
 
                     // Declare the bindings, which may create a source scope.
-                    let remainder_span = remainder_scope.span(this.tcx, this.region_scope_tree);
+                    let remainder_span =
+                        remainder_scope.span(this.tcx, &this.typeck_results.region_scope_tree);
 
                     let visibility_scope =
                         Some(this.new_source_scope(remainder_span, LintLevel::Inherited, None));
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index fbe08dd6f0e..56acf65d9c5 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -699,7 +699,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         self.cfg.push(block, Statement { source_info, kind: StatementKind::StorageLive(local_id) });
         // Altough there is almost always scope for given variable in corner cases
         // like #92893 we might get variable with no scope.
-        if let Some(region_scope) = self.region_scope_tree.var_scope(var.local_id) && schedule_drop{
+        if let Some(region_scope) = self.typeck_results.region_scope_tree.var_scope(var.local_id) && schedule_drop{
             self.schedule_drop(span, region_scope, local_id, DropKind::Storage);
         }
         Place::from(local_id)
@@ -712,7 +712,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         for_guard: ForGuard,
     ) {
         let local_id = self.var_local_id(var, for_guard);
-        if let Some(region_scope) = self.region_scope_tree.var_scope(var.local_id) {
+        if let Some(region_scope) = self.typeck_results.region_scope_tree.var_scope(var.local_id) {
             self.schedule_drop(span, region_scope, local_id, DropKind::Value);
         }
     }
diff --git a/compiler/rustc_mir_build/src/build/mod.rs b/compiler/rustc_mir_build/src/build/mod.rs
index 4ae74433df6..c42f2b3a67a 100644
--- a/compiler/rustc_mir_build/src/build/mod.rs
+++ b/compiler/rustc_mir_build/src/build/mod.rs
@@ -398,7 +398,6 @@ struct Builder<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     infcx: &'a InferCtxt<'a, 'tcx>,
     typeck_results: &'tcx TypeckResults<'tcx>,
-    region_scope_tree: &'tcx region::ScopeTree,
     param_env: ty::ParamEnv<'tcx>,
 
     thir: &'a Thir<'tcx>,
@@ -881,7 +880,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             tcx,
             infcx,
             typeck_results: tcx.typeck_opt_const_arg(def),
-            region_scope_tree: tcx.region_scope_tree(def.did),
             param_env,
             def_id: def.did.to_def_id(),
             hir_id,
diff --git a/compiler/rustc_mir_build/src/build/scope.rs b/compiler/rustc_mir_build/src/build/scope.rs
index 2d14a78accf..53f9706f021 100644
--- a/compiler/rustc_mir_build/src/build/scope.rs
+++ b/compiler/rustc_mir_build/src/build/scope.rs
@@ -916,7 +916,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
 
             if scope.region_scope == region_scope {
-                let region_scope_span = region_scope.span(self.tcx, &self.region_scope_tree);
+                let region_scope_span =
+                    region_scope.span(self.tcx, &self.typeck_results.region_scope_tree);
                 // Attribute scope exit drops to scope's closing brace.
                 let scope_end = self.tcx.sess.source_map().end_point(region_scope_span);
 
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index b9879b9159f..480c5b195cc 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -32,7 +32,8 @@ impl<'tcx> Cx<'tcx> {
     }
 
     pub(super) fn mirror_expr_inner(&mut self, hir_expr: &'tcx hir::Expr<'tcx>) -> ExprId {
-        let temp_lifetime = self.region_scope_tree.temporary_scope(hir_expr.hir_id.local_id);
+        let temp_lifetime =
+            self.rvalue_scopes.temporary_scope(self.region_scope_tree, hir_expr.hir_id.local_id);
         let expr_scope =
             region::Scope { id: hir_expr.hir_id.local_id, data: region::ScopeData::Node };
 
@@ -161,7 +162,8 @@ impl<'tcx> Cx<'tcx> {
         let tcx = self.tcx;
         let expr_ty = self.typeck_results().expr_ty(expr);
         let expr_span = expr.span;
-        let temp_lifetime = self.region_scope_tree.temporary_scope(expr.hir_id.local_id);
+        let temp_lifetime =
+            self.rvalue_scopes.temporary_scope(self.region_scope_tree, expr.hir_id.local_id);
 
         let kind = match expr.kind {
             // Here comes the interesting stuff:
@@ -575,7 +577,9 @@ impl<'tcx> Cx<'tcx> {
             },
             hir::ExprKind::Loop(ref body, ..) => {
                 let block_ty = self.typeck_results().node_type(body.hir_id);
-                let temp_lifetime = self.region_scope_tree.temporary_scope(body.hir_id.local_id);
+                let temp_lifetime = self
+                    .rvalue_scopes
+                    .temporary_scope(self.region_scope_tree, body.hir_id.local_id);
                 let block = self.mirror_block(body);
                 let body = self.thir.exprs.push(Expr {
                     ty: block_ty,
@@ -776,7 +780,8 @@ impl<'tcx> Cx<'tcx> {
         span: Span,
         overloaded_callee: Option<(DefId, SubstsRef<'tcx>)>,
     ) -> Expr<'tcx> {
-        let temp_lifetime = self.region_scope_tree.temporary_scope(expr.hir_id.local_id);
+        let temp_lifetime =
+            self.rvalue_scopes.temporary_scope(self.region_scope_tree, expr.hir_id.local_id);
         let (def_id, substs, user_ty) = match overloaded_callee {
             Some((def_id, substs)) => (def_id, substs, None),
             None => {
@@ -863,7 +868,9 @@ impl<'tcx> Cx<'tcx> {
             // a constant reference (or constant raw pointer for `static mut`) in MIR
             Res::Def(DefKind::Static(_), id) => {
                 let ty = self.tcx.static_ptr_ty(id);
-                let temp_lifetime = self.region_scope_tree.temporary_scope(expr.hir_id.local_id);
+                let temp_lifetime = self
+                    .rvalue_scopes
+                    .temporary_scope(self.region_scope_tree, expr.hir_id.local_id);
                 let kind = if self.tcx.is_thread_local_static(id) {
                     ExprKind::ThreadLocalRef(id)
                 } else {
@@ -939,7 +946,8 @@ impl<'tcx> Cx<'tcx> {
 
         // construct the complete expression `foo()` for the overloaded call,
         // which will yield the &T type
-        let temp_lifetime = self.region_scope_tree.temporary_scope(expr.hir_id.local_id);
+        let temp_lifetime =
+            self.rvalue_scopes.temporary_scope(self.region_scope_tree, expr.hir_id.local_id);
         let fun = self.method_callee(expr, span, overloaded_callee);
         let fun = self.thir.exprs.push(fun);
         let fun_ty = self.thir[fun].ty;
@@ -959,7 +967,9 @@ impl<'tcx> Cx<'tcx> {
         closure_expr: &'tcx hir::Expr<'tcx>,
         place: HirPlace<'tcx>,
     ) -> Expr<'tcx> {
-        let temp_lifetime = self.region_scope_tree.temporary_scope(closure_expr.hir_id.local_id);
+        let temp_lifetime = self
+            .rvalue_scopes
+            .temporary_scope(self.region_scope_tree, closure_expr.hir_id.local_id);
         let var_ty = place.base_ty;
 
         // The result of capture analysis in `rustc_typeck/check/upvar.rs`represents a captured path
@@ -1014,7 +1024,9 @@ impl<'tcx> Cx<'tcx> {
         let upvar_capture = captured_place.info.capture_kind;
         let captured_place_expr =
             self.convert_captured_hir_place(closure_expr, captured_place.place.clone());
-        let temp_lifetime = self.region_scope_tree.temporary_scope(closure_expr.hir_id.local_id);
+        let temp_lifetime = self
+            .rvalue_scopes
+            .temporary_scope(self.region_scope_tree, closure_expr.hir_id.local_id);
 
         match upvar_capture {
             ty::UpvarCapture::ByValue => captured_place_expr,
diff --git a/compiler/rustc_mir_build/src/thir/cx/mod.rs b/compiler/rustc_mir_build/src/thir/cx/mod.rs
index 81eb7efad37..13b4e90ca09 100644
--- a/compiler/rustc_mir_build/src/thir/cx/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/mod.rs
@@ -16,7 +16,7 @@ use rustc_middle::middle::region;
 use rustc_middle::mir::interpret::{LitToConstError, LitToConstInput};
 use rustc_middle::mir::ConstantKind;
 use rustc_middle::thir::*;
-use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::ty::{self, RvalueScopes, Ty, TyCtxt};
 use rustc_span::Span;
 
 pub(crate) fn thir_body<'tcx>(
@@ -51,6 +51,7 @@ struct Cx<'tcx> {
 
     pub(crate) region_scope_tree: &'tcx region::ScopeTree,
     pub(crate) typeck_results: &'tcx ty::TypeckResults<'tcx>,
+    pub(crate) rvalue_scopes: &'tcx RvalueScopes,
 
     /// When applying adjustments to the expression
     /// with the given `HirId`, use the given `Span`,
@@ -71,8 +72,9 @@ impl<'tcx> Cx<'tcx> {
             tcx,
             thir: Thir::new(),
             param_env: tcx.param_env(def.did),
-            region_scope_tree: tcx.region_scope_tree(def.did),
+            region_scope_tree: &typeck_results.region_scope_tree,
             typeck_results,
+            rvalue_scopes: &typeck_results.rvalue_scopes,
             body_owner: def.did.to_def_id(),
             adjustment_span: None,
         }