[Macros] Don't visit macro-generated extensions in visitAuxiliaryDecls.

lib/AST/Decl.cpp

@@ -407,20 +407,6 @@ void Decl::visitAuxiliaryDecls(
     }
   }
 
-  if (auto *nominal = dyn_cast<NominalTypeDecl>(mutableThis)) {
-    auto conformanceBuffers =
-        evaluateOrDefault(ctx.evaluator,
-                          ExpandConformanceMacros{nominal},
-                          {});
-    for (auto bufferID : conformanceBuffers) {
-      auto startLoc = sourceMgr.getLocForBufferStart(bufferID);
-      auto *sourceFile = moduleDecl->getSourceFileContainingLocation(startLoc);
-      for (auto *extension : sourceFile->getTopLevelDecls()) {
-        callback(extension);
-      }
-    }
-  }
-
   if (visitFreestandingExpanded) {
     if (auto *med = dyn_cast<MacroExpansionDecl>(mutableThis)) {
       if (auto bufferID = evaluateOrDefault(

lib/AST/Module.cpp

@@ -4104,8 +4104,7 @@ void FileUnit::getTopLevelDeclsWithAuxiliaryDecls(
   getTopLevelDecls(nonExpandedDecls);
   for (auto *decl : nonExpandedDecls) {
     decl->visitAuxiliaryDecls([&](Decl *auxDecl) {
-      if (!isa<ExtensionDecl>(auxDecl))
-        results.push_back(auxDecl);
+      results.push_back(auxDecl);
     });
     results.push_back(decl);
   }

lib/IRGen/GenDecl.cpp

@@ -5578,11 +5578,6 @@ void IRGenModule::emitNestedTypeDecls(DeclRange members) {
       continue;
 
     member->visitAuxiliaryDecls([&](Decl *decl) {
-      // FIXME: Conformance macros can generate extension decls. These
-      // are visited as top-level decls; skip them here.
-      if (isa<ExtensionDecl>(decl))
-        return;
-
       emitNestedTypeDecls({decl, nullptr});
     });
     switch (member->getKind()) {

lib/Index/Index.cpp

@@ -1148,6 +1148,9 @@ void IndexSwiftASTWalker::visitModule(ModuleDecl &Mod) {
     if (!handleSourceOrModuleFile(*SrcFile))
       return;
     walk(*SrcFile);
+    if (auto *synthesizedSF = SrcFile->getSynthesizedFile()) {
+      walk(synthesizedSF);
+    }
   } else {
     IsModuleFile = true;
     isSystemModule = Mod.isNonUserModule();

lib/SILGen/SILGen.cpp

@@ -2201,10 +2201,6 @@ class SILGenModuleRAII {
     for (auto *D : sf->getTopLevelDecls()) {
       // Emit auxiliary decls.
       D->visitAuxiliaryDecls([&](Decl *auxiliaryDecl) {
-        // Skip extensions decls; they are visited below.
-        if (isa<ExtensionDecl>(auxiliaryDecl))
-          return;
-
         FrontendStatsTracer StatsTracer(SGM.getASTContext().Stats,
                                         "SILgen-decl", auxiliaryDecl);
         SGM.visit(auxiliaryDecl);

lib/SILGen/SILGenType.cpp

@@ -1101,11 +1101,6 @@ class SILGenType : public TypeMemberVisitor<SILGenType> {
     SGM.emitLazyConformancesForType(theType);
 
     forEachMemberToLower(theType, [&](Decl *member) {
-      // FIXME: Conformance macros can generate extension decls. These
-      // are visited as top-level decls; skip them here.
-      if (isa<ExtensionDecl>(member))
-        return;
-
       visit(member);
     });
 

lib/Sema/TypeCheckMacros.cpp

@@ -1442,7 +1442,13 @@ swift::expandConformances(CustomAttr *attr, MacroDecl *macro,
     extension->setExtendedNominal(nominal);
     nominal->addExtension(extension);
 
-    // Make it accessible to getTopLevelDecls()
+    // Most other macro-generated declarations are visited through calling
+    // 'visitAuxiliaryDecls' on the original declaration the macro is attached
+    // to. We don't do this for macro-generated extensions, because the
+    // extension is not a peer of the original declaration. Instead of
+    // requiring all callers of 'visitAuxiliaryDecls' to understand the
+    // hoisting behavior of macro-generated extensions, we make the
+    // extension accessible through 'getTopLevelDecls()'.
     if (auto file = dyn_cast<FileUnit>(
             decl->getDeclContext()->getModuleScopeContext()))
       file->getOrCreateSynthesizedFile().addTopLevelDecl(extension);

lib/Sema/TypeChecker.cpp

@@ -297,6 +297,16 @@ TypeCheckSourceFileRequest::evaluate(Evaluator &eval, SourceFile *SF) const {
       }
     }
 
+    // Type-check macro-generated extensions.
+    if (auto *synthesizedSF = SF->getSynthesizedFile()) {
+      for (auto *decl : synthesizedSF->getTopLevelDecls()) {
+        if (!decl->isImplicit()) {
+          assert(isa<ExtensionDecl>(decl));
+          TypeChecker::typeCheckDecl(decl);
+        }
+      }
+    }
+
     typeCheckDelayedFunctions(*SF);
   }
 

test/Index/index_macros.swift

@@ -81,6 +81,12 @@ struct AddOne {
 // CHECK: [[@LINE-5]]:1 | function/Swift | freeLog() | [[FREE_LOG_USR]] | Ref,Call,Impl,RelCall,RelCont
 // CHECK-NEXT: RelCall,RelCont | instance-method/Swift | freeFunc() | [[FREE_FUNC_USR]]
 
+func testExpr() {
+  #freestandingExpr
+  // CHECK: [[@LINE-1]]:3 | function/Swift | exprLog() | [[EXPR_LOG_USR]] | Ref,Call,Impl,RelCall,RelCont
+  // CHECK-NEXT: RelCall,RelCont | function/Swift | testExpr()
+}
+
 // CHECK: [[@LINE+4]]:40 | macro/Swift | Peer() | [[PEER_USR]] | Ref
 // CHECK: [[@LINE+3]]:23 | macro/Swift | MemberAttribute() | [[MEMBER_ATTRIBUTE_USR]] | Ref
 // CHECK: [[@LINE+2]]:15 | macro/Swift | Member() | [[MEMBER_USR]] | Ref
@@ -112,11 +118,6 @@ struct TestAttached {
 // CHECK: [[@LINE-24]]:39 | function/Swift | peerLog() | [[PEER_LOG_USR]] | Ref,Call,Impl,RelCall,RelCont
 // CHECK-NEXT: RelCall,RelCont | instance-method/Swift | peerFunc() | [[PEER_FUNC_USR]]
 
-// `Conformance` adds `TestProto` as a conformance on an extension of `TestAttached`
-// CHECK: [[@LINE-28]]:1 | extension/ext-struct/Swift | TestAttached | {{.*}} | Def,Impl
-// CHECK: [[@LINE-29]]:1 | protocol/Swift | TestProto | [[PROTO_USR]] | Ref,Impl,RelBase
-// CHECK-NEXT: RelBase | extension/ext-struct/Swift | TestAttached
-
 // CHECK: [[@LINE+1]]:8 | struct/Swift | Outer | [[OUTER_USR:.*]] | Def
 struct Outer {
   // CHECK: [[@LINE+1]]:4 | macro/Swift | PeerMember() | [[PEER_MEMBER_USR]] | Ref
@@ -137,16 +138,19 @@ struct Outer {
 // CHECK: [[@LINE-6]]:16 | function/Swift | memberLog() | [[MEMBER_LOG_USR]] | Ref,Call,Impl,RelCall,RelCont
 // CHECK-NEXT: RelCall,RelCont | instance-method/Swift | memberFunc() | [[INNER_FUNC_USR]]
 
+
+// Expanded extensions are visited last
+
+// `Conformance` adds `TestProto` as a conformance on an extension of `TestAttached`
+// CHECK: [[@LINE-51]]:1 | extension/ext-struct/Swift | TestAttached | {{.*}} | Def,Impl
+// CHECK: [[@LINE-52]]:1 | protocol/Swift | TestProto | [[PROTO_USR]] | Ref,Impl,RelBase
+// CHECK-NEXT: RelBase | extension/ext-struct/Swift | TestAttached
+
 // `Conformance` adds `TestProto` as a conformance on an extension of `TestInner`
-// CHECK: [[@LINE-10]]:3 | extension/ext-struct/Swift | TestInner | {{.*}} | Def,Impl
-// CHECK: [[@LINE-11]]:3 | protocol/Swift | TestProto | [[PROTO_USR]] | Ref,Impl,RelBase
+// CHECK: [[@LINE-18]]:3 | extension/ext-struct/Swift | TestInner | {{.*}} | Def,Impl
+// CHECK: [[@LINE-19]]:3 | protocol/Swift | TestProto | [[PROTO_USR]] | Ref,Impl,RelBase
 // CHECK-NEXT: RelBase | extension/ext-struct/Swift | TestInner
 
-func testExpr() {
-  #freestandingExpr
-  // CHECK: [[@LINE-1]]:3 | function/Swift | exprLog() | [[EXPR_LOG_USR]] | Ref,Call,Impl,RelCall,RelCont
-  // CHECK-NEXT: RelCall,RelCont | function/Swift | testExpr()
-}
 
 //--- IndexMacros.swift
 import SwiftSyntax

test/Macros/macro_expand_conformances.swift

@@ -63,6 +63,12 @@ requireHashable(S2())
 
 requireEquatable(E.Nested())
 
+extension E {
+  @Equatable struct NestedInExtension {}
+}
+
+requireEquatable(E.NestedInExtension())
+
 #if TEST_DIAGNOSTICS
 requireEquatable(PublicEquatable())