apply rules by span edition

rust-lang · Jun 27, 2024 · 9804d04 · 9804d04
1 parent 9d9ba75
commit 9804d04
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Showing 5 changed files with 32 additions and 14 deletions.
diff --git a/compiler/rustc_hir_analysis/src/check/region.rs b/compiler/rustc_hir_analysis/src/check/region.rs
@@ -471,7 +471,12 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
 
         hir::ExprKind::If(cond, then, Some(otherwise)) => {
             let expr_cx = visitor.cx;
-            visitor.enter_scope(Scope { id: then.hir_id.local_id, data: ScopeData::IfThen });
+            let data = if expr.span.at_least_rust_2024() && visitor.tcx.features().if_let_rescope {
+                ScopeData::IfThen2024
+            } else {
+                ScopeData::IfThen
+            };
+            visitor.enter_scope(Scope { id: then.hir_id.local_id, data });
             visitor.cx.var_parent = visitor.cx.parent;
             visitor.visit_expr(cond);
             visitor.visit_expr(then);
@@ -481,7 +486,12 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
 
         hir::ExprKind::If(cond, then, None) => {
             let expr_cx = visitor.cx;
-            visitor.enter_scope(Scope { id: then.hir_id.local_id, data: ScopeData::IfThen });
+            let data = if expr.span.at_least_rust_2024() && visitor.tcx.features().if_let_rescope {
+                ScopeData::IfThen2024
+            } else {
+                ScopeData::IfThen
+            };
+            visitor.enter_scope(Scope { id: then.hir_id.local_id, data });
             visitor.cx.var_parent = visitor.cx.parent;
             visitor.visit_expr(cond);
             visitor.visit_expr(then);

diff --git a/compiler/rustc_hir_typeck/src/rvalue_scopes.rs b/compiler/rustc_hir_typeck/src/rvalue_scopes.rs
@@ -70,8 +70,7 @@ pub fn resolve_rvalue_scopes<'a, 'tcx>(
     def_id: DefId,
 ) -> RvalueScopes {
     let tcx = &fcx.tcx;
-    let mut rvalue_scopes =
-        RvalueScopes::new(tcx.features().if_let_rescope && tcx.sess.at_least_rust_2024());
+    let mut rvalue_scopes = RvalueScopes::new();
     debug!("start resolving rvalue scopes, def_id={def_id:?}");
     debug!("rvalue_scope: rvalue_candidates={:?}", scope_tree.rvalue_candidates);
     for (&hir_id, candidate) in &scope_tree.rvalue_candidates {

diff --git a/compiler/rustc_middle/src/middle/region.rs b/compiler/rustc_middle/src/middle/region.rs
@@ -95,6 +95,7 @@ impl fmt::Debug for Scope {
             ScopeData::Arguments => write!(fmt, "Arguments({:?})", self.id),
             ScopeData::Destruction => write!(fmt, "Destruction({:?})", self.id),
             ScopeData::IfThen => write!(fmt, "IfThen({:?})", self.id),
+            ScopeData::IfThen2024 => write!(fmt, "IfThen[edition2024]({:?})", self.id),
             ScopeData::Remainder(fsi) => write!(
                 fmt,
                 "Remainder {{ block: {:?}, first_statement_index: {}}}",
@@ -125,6 +126,11 @@ pub enum ScopeData {
     /// Used for variables introduced in an if-let expression.
     IfThen,
 
+    /// Edition 2024: Scope of the condition and then block of an if expression
+    /// Used for variables introduced in an if-let expression,
+    /// whose lifetimes do not cross beyond this scope.
+    IfThen2024,
+
     /// Scope following a `let id = expr;` binding in a block.
     Remainder(FirstStatementIndex),
 }

diff --git a/compiler/rustc_middle/src/ty/rvalue_scopes.rs b/compiler/rustc_middle/src/ty/rvalue_scopes.rs
@@ -8,13 +8,12 @@ use tracing::debug;
 /// rules laid out in `rustc_hir_analysis::check::rvalue_scopes`.
 #[derive(TyEncodable, TyDecodable, Clone, Debug, Default, Eq, PartialEq, HashStable)]
 pub struct RvalueScopes {
-    rescope_if_let: bool,
     map: ItemLocalMap<Option<Scope>>,
 }
 
 impl RvalueScopes {
-    pub fn new(rescope_if_let: bool) -> Self {
-        Self { rescope_if_let, map: <_>::default() }
+    pub fn new() -> Self {
+        Self { map: <_>::default() }
     }
 
     /// Returns the scope when the temp created by `expr_id` will be cleaned up.
@@ -41,16 +40,14 @@ impl RvalueScopes {
                     debug!("temporary_scope({expr_id:?}) = {id:?} [enclosing]");
                     return Some(id);
                 }
-                ScopeData::IfThen => {
-                    if self.rescope_if_let {
-                        debug!("temporary_scope({expr_id:?}) = {p:?} [enclosing]");
-                        return Some(p);
-                    }
-                    id = p;
+                ScopeData::IfThen2024 => {
+                    debug!("temporary_scope({expr_id:?}) = {p:?} [enclosing]");
+                    return Some(p);
                 }
                 ScopeData::Node
                 | ScopeData::CallSite
                 | ScopeData::Arguments
+                | ScopeData::IfThen
                 | ScopeData::Remainder(_) => id = p,
             }
         }

diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -712,7 +712,13 @@ impl<'tcx> Cx<'tcx> {
             hir::ExprKind::If(cond, then, else_opt) => ExprKind::If {
                 if_then_scope: region::Scope {
                     id: then.hir_id.local_id,
-                    data: region::ScopeData::IfThen,
+                    data: {
+                        if expr.span.at_least_rust_2024() && tcx.features().if_let_rescope {
+                            region::ScopeData::IfThen2024
+                        } else {
+                            region::ScopeData::IfThen
+                        }
+                    },
                 },
                 cond: self.mirror_expr(cond),
                 then: self.mirror_expr(then),