Merge pull request #65554 from adrian-prantl/107030837-5.9

Remove a stateful workaround for Property Wrappers.

Author: adrian-prantl

lib/SIL/Verifier/SILVerifier.cpp

@@ -6302,6 +6302,15 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
       // inherit the sourrounding scope in IRGenSIL.
       if (SI.getLoc().getKind() == SILLocation::MandatoryInlinedKind)
         continue;
+      // FIXME: There are situations where the execution legitimately goes
+      //        backwards, such as
+      //
+      //            while case let w: String? = Optional.some("b") {}
+      //
+      //        where the RHS of the assignment gets run first and then the
+      //        result is copied into the LHS.
+      if (!llvm::isa<BeginBorrowInst>(&SI) || !llvm::isa<CopyValueInst>(&SI))
+        continue;
 
       // If we haven't seen this debug scope yet, update the
       // map and go on.

lib/SILGen/SILGenFunction.cpp

@@ -370,20 +370,9 @@ SILGenFunction::getOrCreateScope(const ast_scope::ASTScopeImpl *ASTScope,
   // Decide whether to pick a parent scope instead.
   if (ASTScope->ignoreInDebugInfo()) {
     LLVM_DEBUG(llvm::dbgs() << "ignored\n");
-    // FIXME: it would be more deterministic to use
-    //        getOrCreateScope(ASTScope->getParent().getPtrOrNull());
-    //        here. Unfortunately property wrappers rearrange AST
-    //        nodes without marking them as implicit, e.g.:
-    //
-    //           @Wrapper(a) var v = b
-    //        ->
-    //           let _tmp = Constructor(a, b); var v = _tmp
-    //
-    //        Since the arguments to Constructor aren't marked as implicit,
-    //        argument b is in the scope of v, but the call to Constructor
-    //        isn't, which correctly triggers the scope hole verifier.
-    auto *CurScope = B.getCurrentDebugScope();
-    return CurScope->InlinedCallSite != InlinedAt ? FnScope : CurScope;
+    auto *ParentScope = getOrCreateScope(ASTScope->getParent().getPtrOrNull(),
+                                         FnScope, InlinedAt);
+    return ParentScope->InlinedCallSite != InlinedAt ? FnScope : ParentScope;
   }
 
   // Collapse BraceStmtScopes whose parent is a .*BodyScope.

test/DebugInfo/guard-let-scope3.swift

@@ -0,0 +1,19 @@
+// RUN: %target-swift-frontend -g -emit-sil %s -parse-as-library -module-name a | %FileCheck %s
+public class C {}
+public enum MyError : Error {
+  init() { self.init() }
+}
+public class S {
+  private var c = [Int : C?]()
+  public func f(_ i: Int) throws  -> C {
+    guard let x = c[i], let x else {
+    // CHECK: sil_scope [[X1:[0-9]+]] { loc "{{.*}}":[[@LINE-1]]:5
+    // CHECK: sil_scope [[X2:[0-9]+]] { loc "{{.*}}":[[@LINE-2]]:29
+    // CHECK: debug_value {{.*}} : $Optional<C>, let, name "x", {{.*}}, scope [[X1]]
+    // CHECK: debug_value %29 : $C, let, name "x", {{.*}}, scope [[X2]]
+    // CHECK-NEXT:  scope [[X2]]
+      throw MyError()
+    }
+    return x
+  }
+}