Merge pull request #30968 from davidungar/rdar-61461187-tolerate-nonempty-brace-in-brace

[ASTScope lookup] Tolerate non-empty braces in braces

Author: David Ungar

lib/AST/ASTScopeCreation.cpp

@@ -658,9 +658,10 @@ class ScopeCreator final {
     ASTScopeAssert(!n.isDecl(DeclKind::Accessor),
                    "Should not see accessors here");
     // Can occur in illegal code
+    // non-empty brace stmt could define a new insertion point
     if (auto *const s = n.dyn_cast<Stmt *>()) {
       if (auto *const bs = dyn_cast<BraceStmt>(s))
-        ASTScopeAssert(bs->empty(), "Might mess up insertion point");
+        return !bs->empty();
     }
     return !n.isDecl(DeclKind::Var);
   }

test/NameLookup/nonempty-brace-in-brace.swift

@@ -0,0 +1,12 @@
+// RUN: not %target-swift-frontend -typecheck %s  2>&1 |  %FileCheck %s --check-prefix=CHECK-NO-ASSERTION
+
+// Used to trip an assertion
+
+public struct Foo {
+    func bar() {
+        var copySelf = self
+        repeat { copySelf
+
+private extension String {}
+
+// CHECK-NO-ASSERTION-NOT: Assertion