recognise data contructor calls

Author: dingxiangfei2009

compiler/rustc_hir_analysis/src/check/scope_map.rs

@@ -164,6 +164,21 @@ impl<'tcx> ScopeCollector<'tcx> {
             cx: Context { temp_lifetime: TemporaryLifetimeScopes::new_static(), var_parent: None },
         }
     }
+
+    fn is_data_constructor(&self, callee: &hir::Expr<'_>) -> bool {
+        match callee.kind {
+            hir::ExprKind::Path(hir::QPath::Resolved(
+                _,
+                hir::Path {
+                    res:
+                        hir::def::Res::Def(hir::def::DefKind::Ctor(_, _), _)
+                        | hir::def::Res::SelfCtor(_),
+                    ..
+                },
+            )) => true,
+            _ => false,
+        }
+    }
 }
 
 impl<'tcx> ScopeCollector<'tcx> {
@@ -336,7 +351,7 @@ impl<'tcx> Visitor<'tcx> for ScopeCollector<'tcx> {
             }
 
             hir::ExprKind::Struct(_path, fields, struct_base) => {
-                for hir::ExprField { expr, .. } in fields {
+                for &hir::ExprField { expr, .. } in fields {
                     self.cx.temp_lifetime = prev_temp_lifetime;
                     self.cx.temp_lifetime.is_result = true;
                     self.visit_expr(expr);
@@ -349,6 +364,14 @@ impl<'tcx> Visitor<'tcx> for ScopeCollector<'tcx> {
                 }
             }
 
+            hir::ExprKind::Call(callee, args) if self.is_data_constructor(callee) => {
+                for expr in args {
+                    self.cx.temp_lifetime = prev_temp_lifetime;
+                    self.cx.temp_lifetime.is_result = true;
+                    self.visit_expr(expr);
+                }
+            }
+
             hir::ExprKind::Tup(subexprs) => {
                 for subexpr in subexprs {
                     self.cx.temp_lifetime = prev_temp_lifetime;

tests/ui/binding/super-let-positive.rs

@@ -21,6 +21,14 @@ fn example2() -> usize {
     *x.lock().unwrap()
 }
 
+fn example3() {
+    enum Enum<'a> {
+        A(&'a u8),
+    }
+    fn compute() -> u8 { 1 }
+    let x = Enum::A(&compute());
+}
+
 struct A;
 impl A {
     #[inline(never)]