Improve and collate diagnostics for uses of unsafe constructs in declarations

include/swift/AST/DiagnosticsSema.def

@@ -8072,6 +8072,24 @@ NOTE(sending_function_result_with_sending_param_note, none,
 //------------------------------------------------------------------------------
 ERROR(unsafe_attr_disabled,none,
       "attribute requires '-enable-experimental-feature AllowUnsafeAttribute'", ())
+
+GROUPED_WARNING(decl_involves_unsafe,Unsafe,none,
+      "%kindbase0 involves unsafe code; "
+      "use %select{'@unsafe' to indicate that its use is not memory-safe|"
+      "'@safe(unchecked)' to assert that the code is memory-safe}1",
+      (const Decl *, bool))
+NOTE(note_reference_to_unsafe_decl,none,
+      "%select{reference|call}0 to unsafe %kind1",
+      (bool, const ValueDecl *))
+NOTE(note_reference_to_unsafe_typed_decl,none,
+     "%select{reference|call}0 to %kind1 involves unsafe type %2",
+     (bool, const ValueDecl *, Type))
+NOTE(note_reference_to_nonisolated_unsafe,none,
+     "reference to nonisolated(unsafe) %kind0 is unsafe in concurrently-executing code",
+     (const ValueDecl *))
+NOTE(note_reference_unowned_unsafe,none,
+     "reference to unowned(unsafe) %kind0 is unsafe", (const ValueDecl *))
+
 GROUPED_WARNING(override_safe_withunsafe,Unsafe,none,
       "override of safe %0 with unsafe %0", (DescriptiveDeclKind))
 GROUPED_WARNING(witness_unsafe,Unsafe,none,
@@ -8082,10 +8100,11 @@ GROUPED_WARNING(type_witness_unsafe,Unsafe,none,
       (Type, DeclName))
 GROUPED_WARNING(unchecked_conformance_is_unsafe,Unsafe,none,
       "@unchecked conformance involves unsafe code", ())
-GROUPED_WARNING(unowned_unsafe_is_unsafe,Unsafe,none,
-      "unowned(unsafe) involves unsafe code", ())
-GROUPED_WARNING(nonisolated_unsafe_is_unsafe,Unsafe,none,
-      "nonisolated(unsafe) involves unsafe code", ())
+GROUPED_WARNING(reference_unowned_unsafe,Unsafe,none,
+      "reference to unowned(unsafe) %kind0 is unsafe", (const ValueDecl *))
+GROUPED_WARNING(reference_to_nonisolated_unsafe,Unsafe,none,
+      "reference to nonisolated(unsafe) %kind0 is unsafe in concurrently-executing code",
+       (const ValueDecl *))
 GROUPED_WARNING(reference_to_unsafe_decl,Unsafe,none,
       "%select{reference|call}0 to unsafe %kindbase1",
       (bool, const ValueDecl *))

include/swift/AST/SourceFile.h

@@ -27,6 +27,7 @@
 namespace swift {
 
 class PersistentParserState;
+struct SourceFileExtras;
 
 /// Kind of import affecting how a decl can be reexported.
 ///
@@ -243,6 +244,9 @@ class SourceFile final : public FileUnit {
   /// Storage for \c HasImportsMatchingFlagRequest.
   ImportOptions cachedImportOptions;
 
+  /// Extra information for the source file, allocated as needed.
+  SourceFileExtras *extras = nullptr;
+
   friend ASTContext;
 
 public:
@@ -368,6 +372,11 @@ class SourceFile final : public FileUnit {
   /// \c #sourceLocation(file:) declarations.
   llvm::StringMap<SourceFilePathInfo> getInfoForUsedFilePaths() const;
 
+  /// Retrieve "extra" information associated with this source file, which is
+  /// lazily and separately constructed. Use this for scratch information
+  /// that isn't needed for all source files.
+  SourceFileExtras &getExtras() const;
+
   SourceFile(ModuleDecl &M, SourceFileKind K, unsigned bufferID,
              ParsingOptions parsingOpts = {}, bool isPrimary = false);
 

include/swift/AST/SourceFileExtras.h

@@ -0,0 +1,36 @@
+//===--- SourceFileExtras.h - Extra data for a source file ------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_AST_SOURCEFILEEXTRAS_H
+#define SWIFT_AST_SOURCEFILEEXTRAS_H
+
+#include "swift/AST/UnsafeUse.h"
+#include "llvm/ADT/DenseMap.h"
+#include <vector>
+
+namespace swift {
+
+class Decl;
+
+/// Extra information associated with a source file that is lazily created and
+/// stored in a separately-allocated side structure.
+struct SourceFileExtras {
+  /// Captures all of the unsafe uses associated with a given declaration.
+  ///
+  /// The declaration is the entity that can be annotated (e.g., with @unsafe)
+  /// to suppress all of the unsafe-related diagnostics listed here.
+  llvm::DenseMap<const Decl *, std::vector<UnsafeUse>> unsafeUses;
+};
+
+}
+
+#endif // SWIFT_AST_SOURCEFILEEXTRAS_H