[Sema] Record opaque type decls for type reconstruction in OpaqueResultTypeRequest

instead of in the parser.

Author: hborla

Diff for: include/swift/AST/SourceFile.h

@@ -149,9 +149,12 @@ class SourceFile final : public FileUnit {
   /// The set of validated opaque return type decls in the source file.
   llvm::SmallVector<OpaqueTypeDecl *, 4> OpaqueReturnTypes;
   llvm::StringMap<OpaqueTypeDecl *> ValidatedOpaqueReturnTypes;
-  /// The set of parsed decls with opaque return types that have not yet
-  /// been validated.
-  llvm::SetVector<ValueDecl *> UnvalidatedDeclsWithOpaqueReturnTypes;
+  /// The set of opaque type decls that have not yet been validated.
+  ///
+  /// \note This is populated as opaque type decls are created. Validation
+  /// requires mangling the naming decl, which would lead to circularity
+  /// if it were done from OpaqueResultTypeRequest.
+  llvm::SetVector<OpaqueTypeDecl *> UnvalidatedOpaqueReturnTypes;
 
   /// The list of top-level items in the source file. This is \c None if
   /// they have not yet been parsed.
@@ -643,11 +646,8 @@ class SourceFile final : public FileUnit {
 
   OpaqueTypeDecl *lookupOpaqueResultType(StringRef MangledName) override;
 
-  /// Do not call when inside an inactive clause (\c
-  /// InInactiveClauseEnvironment)) because it will later on result in a lookup
-  /// to something that won't be in the ASTScope tree.
-  void addUnvalidatedDeclWithOpaqueResultType(ValueDecl *vd) {
-    UnvalidatedDeclsWithOpaqueReturnTypes.insert(vd);
+  void addOpaqueResultTypeDecl(OpaqueTypeDecl *decl) {
+    UnvalidatedOpaqueReturnTypes.insert(decl);
   }
 
   ArrayRef<OpaqueTypeDecl *> getOpaqueReturnTypeDecls();

Diff for: include/swift/Parse/Parser.h

@@ -177,9 +177,7 @@ class Parser {
 
   bool InPoundLineEnvironment = false;
   bool InPoundIfEnvironment = false;
-  /// Do not call \c addUnvalidatedDeclWithOpaqueResultType when in an inactive
-  /// clause because ASTScopes are not created in those contexts and lookups to
-  /// those decls will fail.
+  /// ASTScopes are not created in inactive clauses and lookups to decls will fail.
   bool InInactiveClauseEnvironment = false;
   bool InSwiftKeyPath = false;
 

Diff for: lib/AST/Module.cpp

@@ -3484,14 +3484,12 @@ void SourceFile::setTypeRefinementContext(TypeRefinementContext *Root) {
 }
 
 ArrayRef<OpaqueTypeDecl *> SourceFile::getOpaqueReturnTypeDecls() {
-  for (auto *vd : UnvalidatedDeclsWithOpaqueReturnTypes.takeVector()) {
-    if (auto opaqueDecl = vd->getOpaqueResultTypeDecl()) {
-      auto inserted = ValidatedOpaqueReturnTypes.insert(
-                {opaqueDecl->getOpaqueReturnTypeIdentifier().str(),
-                 opaqueDecl});
-      if (inserted.second) {
-        OpaqueReturnTypes.push_back(opaqueDecl);
-      }
+  for (auto *opaqueDecl : UnvalidatedOpaqueReturnTypes.takeVector()) {
+    auto inserted = ValidatedOpaqueReturnTypes.insert(
+              {opaqueDecl->getOpaqueReturnTypeIdentifier().str(),
+               opaqueDecl});
+    if (inserted.second) {
+      OpaqueReturnTypes.push_back(opaqueDecl);
     }
   }
 

Diff for: lib/Parse/ParseDecl.cpp

@@ -7235,12 +7235,6 @@ Parser::parseDeclVar(ParseDeclOptions Flags,
       pattern = patternRes.get();
     }
 
-    bool hasOpaqueReturnTy = false;
-    if (auto typedPattern = dyn_cast<TypedPattern>(pattern)) {
-      hasOpaqueReturnTy = typedPattern->getTypeRepr()->hasOpaque();
-    }
-    auto sf = CurDeclContext->getParentSourceFile();
-    
     // Configure all vars with attributes, 'static' and parent pattern.
     pattern->forEachVariable([&](VarDecl *VD) {
       VD->setStatic(StaticLoc.isValid());
@@ -7252,9 +7246,6 @@ Parser::parseDeclVar(ParseDeclOptions Flags,
       setOriginalDeclarationForDifferentiableAttributes(Attributes, VD);
 
       Decls.push_back(VD);
-      if (hasOpaqueReturnTy && sf && !InInactiveClauseEnvironment) {
-        sf->addUnvalidatedDeclWithOpaqueResultType(VD);
-      }
     });
 
     // Check whether we have already established an initializer context.
@@ -7541,14 +7532,6 @@ ParserResult<FuncDecl> Parser::parseDeclFunc(SourceLoc StaticLoc,
                               GenericParams,
                               BodyParams, FuncRetTy,
                               CurDeclContext);
-
-  // Let the source file track the opaque return type mapping, if any.
-  if (FuncRetTy && FuncRetTy->hasOpaque() &&
-      !InInactiveClauseEnvironment) {
-    if (auto sf = CurDeclContext->getParentSourceFile()) {
-      sf->addUnvalidatedDeclWithOpaqueResultType(FD);
-    }
-  }
 
   // Parse a 'where' clause if present.
   if (Tok.is(tok::kw_where)) {
@@ -8512,14 +8495,6 @@ Parser::parseDeclSubscript(SourceLoc StaticLoc,
       Context, name, StaticLoc, StaticSpelling, SubscriptLoc, Indices.get(),
       ArrowLoc, ElementTy.get(), CurDeclContext, GenericParams);
   Subscript->getAttrs() = Attributes;
-  
-  // Let the source file track the opaque return type mapping, if any.
-  if (ElementTy.get() && ElementTy.get()->hasOpaque() &&
-      !InInactiveClauseEnvironment) {
-    if (auto sf = CurDeclContext->getParentSourceFile()) {
-      sf->addUnvalidatedDeclWithOpaqueResultType(Subscript);
-    }
-  }
 
   DefaultArgs.setFunctionContext(Subscript, Subscript->getIndices());
 

Diff for: lib/Sema/TypeCheckGeneric.cpp

@@ -251,6 +251,13 @@ OpaqueResultTypeRequest::evaluate(Evaluator &evaluator,
 
   auto metatype = MetatypeType::get(interfaceType);
   opaqueDecl->setInterfaceType(metatype);
+
+  // Record the opaque return type decl in the parent source file,
+  // which will be used in IRGen to emit all opaque type decls
+  // in a Swift module for type reconstruction.
+  if (auto *sourceFile = dc->getParentSourceFile())
+    sourceFile->addOpaqueResultTypeDecl(opaqueDecl);
+
   return opaqueDecl;
 }