Remove old unqualified lookup implementation

include/swift/Basic/LangOptions.h

@@ -254,9 +254,6 @@ namespace swift {
     /// Should  we stress ASTScope-based resolution for debugging?
     bool StressASTScopeLookup = false;
 
-    /// Build the ASTScope tree lazily
-    bool LazyASTScopes = true;
-
     /// Whether to enable the new operator decl and precedencegroup lookup
     /// behavior. This is a staging flag, and will be removed in the future.
     bool EnableNewOperatorLookup = false;

include/swift/Option/FrontendOptions.td

@@ -160,9 +160,6 @@ def crosscheck_unqualified_lookup : Flag<["-"], "crosscheck-unqualified-lookup">
 def stress_astscope_lookup : Flag<["-"], "stress-astscope-lookup">,
   HelpText<"Stress ASTScope-based unqualified name lookup (for testing)">;
 
-def lazy_astscopes : Flag<["-"], "lazy-astscopes">,
-  HelpText<"Build ASTScopes lazily">;
-
 def use_clang_function_types : Flag<["-"], "use-clang-function-types">,
   HelpText<"Use stored Clang function types for computing canonical types.">;
 

lib/AST/ASTScopeCreation.cpp

@@ -354,10 +354,10 @@ class ScopeCreator final {
   ASTScopeImpl *constructExpandAndInsert(ASTScopeImpl *parent, Args... args) {
     auto *child = new (ctx) Scope(args...);
     parent->addChild(child, ctx);
-    if (shouldBeLazy()) {
-      if (auto *ip = child->insertionPointForDeferredExpansion().getPtrOrNull())
-        return ip;
-    }
+
+    if (auto *ip = child->insertionPointForDeferredExpansion().getPtrOrNull())
+      return ip;
+
     ASTScopeImpl *insertionPoint =
         child->expandAndBeCurrentDetectingRecursion(*this);
     ASTScopeAssert(child->verifyThatThisNodeComeAfterItsPriorSibling(),
@@ -646,8 +646,6 @@ class ScopeCreator final {
     return !n.isDecl(DeclKind::Var);
   }
 
-  bool shouldBeLazy() const { return ctx.LangOpts.LazyASTScopes; }
-
 public:
   /// For debugging. Return true if scope tree contains all the decl contexts in
   /// the AST May modify the scope tree in order to update obsolete scopes.
@@ -1121,14 +1119,13 @@ ASTScopeImpl *ASTScopeImpl::expandAndBeCurrent(ScopeCreator &scopeCreator) {
     disownDescendants(scopeCreator);
 
   auto *insertionPoint = expandSpecifically(scopeCreator);
-  if (scopeCreator.shouldBeLazy()) {
-    ASTScopeAssert(!insertionPointForDeferredExpansion() ||
-                       insertionPointForDeferredExpansion().get() ==
-                           insertionPoint,
-                   "In order for lookups into lazily-expanded scopes to be "
-                   "accurate before expansion, the insertion point before "
-                   "expansion must be the same as after expansion.");
-  }
+  ASTScopeAssert(!insertionPointForDeferredExpansion() ||
+                     insertionPointForDeferredExpansion().get() ==
+                         insertionPoint,
+                 "In order for lookups into lazily-expanded scopes to be "
+                 "accurate before expansion, the insertion point before "
+                 "expansion must be the same as after expansion.");
+
   replaceASTAncestorScopes(astAncestorScopes);
   setWasExpanded();
   beCurrent();

lib/AST/ASTScopeSourceRange.cpp

@@ -526,8 +526,6 @@ void ASTScopeImpl::computeAndCacheSourceRangeOfScope(
 }
 
 bool ASTScopeImpl::checkLazySourceRange(const ASTContext &ctx) const {
-  if (!ctx.LangOpts.LazyASTScopes)
-    return true;
   const auto unexpandedRange = sourceRangeForDeferredExpansion();
   const auto expandedRange = computeSourceRangeOfScopeWithChildASTNodes();
   if (unexpandedRange.isInvalid() || expandedRange.isInvalid())