Sema: Don't visit elements of a BraceStmt twice when checking availability

Author: slavapestov

lib/Sema/TypeCheckAvailability.cpp

@@ -2959,6 +2959,14 @@ class StmtAvailabilityWalker : public ASTWalker {
   explicit StmtAvailabilityWalker(ExportContext where)
     : Where(where) {}
 
+  /// We'll visit each element of a BraceStmt individually.
+  std::pair<bool, Stmt *> walkToStmtPre(Stmt *S) override {
+    if (isa<BraceStmt>(S))
+      return std::make_pair(false, S);
+
+    return std::make_pair(true, S);
+  }
+
   /// We'll visit the expression from performSyntacticExprDiagnostics().
   std::pair<bool, Expr *> walkToExprPre(Expr *E) override {
     return std::make_pair(false, E);

test/attr/attr_inlinable.swift

@@ -18,8 +18,8 @@ func internalFunction() {}
 public func publicFunction() {}
 
 private struct PrivateStruct {}
-// expected-note@-1 3{{struct 'PrivateStruct' is not '@usableFromInline' or public}}
-// expected-note@-2 {{initializer 'init()' is not '@usableFromInline' or public}}
+// expected-note@-1 5{{struct 'PrivateStruct' is not '@usableFromInline' or public}}
+// expected-note@-2 2{{initializer 'init()' is not '@usableFromInline' or public}}
 struct InternalStruct {}
 // expected-note@-1 3{{struct 'InternalStruct' is not '@usableFromInline' or public}}
 // expected-note@-2 {{initializer 'init()' is not '@usableFromInline' or public}}
@@ -350,3 +350,10 @@ public struct PrivateInlinableCrash {
   // expected-error@-1 {{'@inlinable' attribute cannot be applied to stored properties}}
 }
 
+@inlinable public func nestedBraceStmtTest() {
+  if true {
+    let _: PrivateStruct = PrivateStruct()
+    // expected-error@-1 2{{struct 'PrivateStruct' is private and cannot be referenced from an '@inlinable' function}}
+    // expected-error@-2 {{initializer 'init()' is private and cannot be referenced from an '@inlinable' function}}
+  }
+}