[TypeChecker] Issue error message when accessing subscript using keyword

include/swift/AST/ASTPrinter.h

@@ -194,7 +194,7 @@ class ASTPrinter {
     return *this;
   }
 
-  void printName(Identifier Name,
+  void printName(DeclName Name,
                  PrintNameContext Context = PrintNameContext::Normal);
 
   void setIndent(unsigned NumSpaces) {

include/swift/AST/Attr.h

@@ -688,21 +688,16 @@ class ObjCAttr final : public DeclAttribute,
     private llvm::TrailingObjects<ObjCAttr, SourceLoc> {
   friend TrailingObjects;
 
-  /// The Objective-C name associated with this entity, stored in its opaque
-  /// representation so that we can use null as an indicator for "no name".
-  void *NameData;
+  /// The Objective-C name associated with this entity
+  Optional<ObjCSelector> Name;
 
   /// Create an implicit @objc attribute with the given (optional) name.
   explicit ObjCAttr(Optional<ObjCSelector> name, bool implicitName)
     : DeclAttribute(DAK_ObjC, SourceLoc(), SourceRange(), /*Implicit=*/true),
-      NameData(nullptr)
+      Name(name)
   {
     ObjCAttrBits.HasTrailingLocationInfo = false;
     ObjCAttrBits.ImplicitName = implicitName;
-
-    if (name) {
-      NameData = name->getOpaqueValue();
-    }
   }
 
   /// Create an @objc attribute written in the source.
@@ -777,14 +772,11 @@ class ObjCAttr final : public DeclAttribute,
                                   bool isNameImplicit);
 
   /// Determine whether this attribute has a name associated with it.
-  bool hasName() const { return NameData != nullptr; }
+  bool hasName() const { return Name.hasValue(); }
 
   /// Retrieve the name of this entity, if specified.
   Optional<ObjCSelector> getName() const {
-    if (!hasName())
-      return None;
-
-    return ObjCSelector::getFromOpaqueValue(NameData);
+    return Name;
   }
 
   /// Determine whether the name associated with this attribute was
@@ -802,13 +794,13 @@ class ObjCAttr final : public DeclAttribute,
       ObjCAttrBits.HasTrailingLocationInfo = false;
     }
 
-    NameData = name.getOpaqueValue();
+    Name = name;
     ObjCAttrBits.ImplicitName = implicit;
   }
 
   /// Clear the name of this entity.
   void clearName() {
-    NameData = nullptr;
+    Name = None;
   }
 
   /// Retrieve the source locations for the names in a non-implicit

include/swift/AST/DebuggerClient.h

@@ -37,7 +37,7 @@ class DebuggerClient {
   // in the global context rather than the current context.
   // This question will only be asked if the decl's current context
   // is a function marked with the LLDBDebuggerFunction attribute.
-  virtual bool shouldGlobalize(Identifier Name, DeclKind kind) = 0;
+  virtual bool shouldGlobalize(DeclName Name, DeclKind kind) = 0;
 
   virtual void didGlobalize (Decl *Decl) = 0;
 
@@ -48,7 +48,7 @@ class DebuggerClient {
   /// be consulted first.  Return true if results have been added
   /// to RV.
   /// FIXME: I don't think this ever does anything useful.
-  virtual bool lookupOverrides(Identifier Name, DeclContext *DC,
+  virtual bool lookupOverrides(DeclName Name, DeclContext *DC,
                                SourceLoc Loc, bool IsTypeLookup,
                                ResultVector &RV) = 0;
 
@@ -57,7 +57,7 @@ class DebuggerClient {
   /// gets a chance to add names to the list of candidates that
   /// have been found in the external module lookup.  
 
-  virtual bool lookupAdditions(Identifier Name, DeclContext *DC,
+  virtual bool lookupAdditions(DeclName Name, DeclContext *DC,
                                SourceLoc Loc, bool IsTypeLookup,
                                ResultVector &RV) = 0;
 

include/swift/AST/Decl.h

@@ -1965,13 +1965,12 @@ class ValueDecl : public Decl {
   }
 
   bool hasName() const { return bool(Name); }
-  /// TODO: Rename to getSimpleName?
-  Identifier getName() const { return Name.getBaseName(); }
+
   bool isOperator() const { return Name.isOperator(); }
 
   /// Returns the string for the base name, or "_" if this is unnamed.
   StringRef getNameStr() const {
-    return hasName() ? getName().str() : "_";
+    return hasName() ? getBaseName().str() : "_";
   }
 
   /// Retrieve the full name of the declaration.
@@ -2186,6 +2185,10 @@ class TypeDecl : public ValueDecl {
   }
 
 public:
+  Identifier getIdentifier() const {
+    return getBaseName().getIdentifier();
+  }
+
   /// The type of this declaration's values. For the type of the
   /// declaration itself, use getInterfaceType(), which returns a
   /// metatype.
@@ -4051,7 +4054,7 @@ class VarDecl : public AbstractStorageDecl {
   llvm::PointerUnion<PatternBindingDecl*, Stmt*> ParentPattern;
 
   VarDecl(DeclKind Kind, bool IsStatic, bool IsLet, SourceLoc NameLoc,
-          Identifier Name, Type Ty, DeclContext *DC)
+          DeclName Name, Type Ty, DeclContext *DC)
     : AbstractStorageDecl(Kind, DC, Name, NameLoc) 
   {
     VarDeclBits.IsUserAccessible = true;
@@ -4068,7 +4071,7 @@ class VarDecl : public AbstractStorageDecl {
   Type typeInContext;
 
 public:
-  VarDecl(bool IsStatic, bool IsLet, SourceLoc NameLoc, Identifier Name,
+  VarDecl(bool IsStatic, bool IsLet, SourceLoc NameLoc, DeclName Name,
           Type Ty, DeclContext *DC)
     : VarDecl(DeclKind::Var, IsStatic, IsLet, NameLoc, Name, Ty, DC) { }
 
@@ -4255,6 +4258,12 @@ class ParamDecl : public VarDecl {
   /// accidental copies.
   ParamDecl(ParamDecl *PD);
 
+  /// Retrieve the identifier for the name of this parameter
+  Identifier getIdentifier() const {
+    // ParamDecls can't carry a special DeclName
+    return getBaseName().getIdentifier();
+  }
+
   /// Retrieve the argument (API) name for this function parameter.
   Identifier getArgumentName() const { return ArgumentName; }
 
@@ -5197,6 +5206,10 @@ class EnumElementDecl : public ValueDecl {
     EnumElementDeclBits.Recursiveness =
         static_cast<unsigned>(ElementRecursiveness::NotRecursive);
   }
+
+  Identifier getIdentifier() {
+    return getBaseName().getIdentifier();
+  }
 
   /// \returns false if there was an error during the computation rendering the
   /// EnumElementDecl invalid, true otherwise.

include/swift/AST/DiagnosticsCommon.def

@@ -50,7 +50,7 @@ ERROR(error_no_group_info,none,
 
 NOTE(previous_decldef,none,
      "previous %select{declaration|definition}0 of %1 is here",
-     (bool, Identifier))
+     (bool, DeclName))
 
 
 // Generic disambiguation

include/swift/AST/DiagnosticsParse.def

@@ -148,7 +148,7 @@ ERROR(lex_conflict_marker_in_file,none,
 //------------------------------------------------------------------------------
 
 NOTE(note_in_decl_extension,none,
-     "in %select{declaration|extension}0 of %1", (bool, Identifier))
+     "in %select{declaration|extension}0 of %1", (bool, DeclName))
 ERROR(line_directive_style_deprecated,none,
         "#line directive was renamed to #sourceLocation",
         ())
@@ -551,9 +551,9 @@ ERROR(multiple_sil_stage_decls, none,
 ERROR(expected_sil_vtable_colon,none,
       "expected ':' in a vtable entry", ())
 ERROR(sil_vtable_func_not_found,none,
-      "sil function not found %0", (Identifier))
+      "sil function not found %0", (DeclName))
 ERROR(sil_vtable_class_not_found,none,
-      "sil class not found %0", (Identifier))
+      "sil class not found %0", (DeclName))
 
 // SIL Global
 ERROR(sil_global_variable_not_found,none,
@@ -567,7 +567,7 @@ ERROR(expected_sil_witness_lparen,none,
 ERROR(expected_sil_witness_rparen,none,
       "expected ')' in a witness table", ())
 ERROR(sil_witness_func_not_found,none,
-      "sil function not found %0", (Identifier))
+      "sil function not found %0", (DeclName))
 ERROR(sil_witness_protocol_not_found,none,
       "sil protocol not found %0", (Identifier))
 ERROR(sil_witness_assoc_not_found,none,
@@ -577,7 +577,7 @@ ERROR(sil_witness_protocol_conformance_not_found,none,
 
 // SIL Coverage Map
 ERROR(sil_coverage_func_not_found, none,
-      "sil function not found %0", (Identifier))
+      "sil function not found %0", (DeclName))
 ERROR(sil_coverage_invalid_hash, none,
       "expected coverage hash", ())
 ERROR(sil_coverage_expected_lbrace, none,
@@ -722,7 +722,7 @@ ERROR(var_pattern_in_var,none,
       "'%select{var|let}0' cannot appear nested inside another 'var' or "
       "'let' pattern", (unsigned))
 ERROR(extra_var_in_multiple_pattern_list,none,
-      "%0 must be bound in every pattern", (Identifier))
+      "%0 must be bound in every pattern", (DeclName))
 ERROR(let_pattern_in_immutable_context,none,
       "'let' pattern cannot appear nested in an already immutable context", ())
 ERROR(inout_must_have_type,none,

include/swift/AST/DiagnosticsSIL.def

@@ -71,7 +71,7 @@ ERROR(could_not_find_pointer_pointee_property,none,
 
 ERROR(writeback_overlap_property,none,
       "inout writeback to computed property %0 occurs in multiple arguments to"
-      " call, introducing invalid aliasing", (Identifier))
+      " call, introducing invalid aliasing", (DeclName))
 ERROR(writeback_overlap_subscript,none,
       "inout writeback through subscript occurs in multiple arguments to call,"
       " introducing invalid aliasing",
@@ -120,7 +120,7 @@ ERROR(self_use_before_fully_init,none,
       "use of 'self' in %select{method call|property access}1 %0 before "
       "%select{all stored properties are initialized|"
       "super.init initializes self|"
-      "self.init initializes self}2", (Identifier, bool, unsigned))
+      "self.init initializes self}2", (DeclName, bool, unsigned))
 ERROR(use_of_self_before_fully_init,none,
       "'self' used before all stored properties are initialized", ())
 ERROR(use_of_self_before_fully_init_protocol,none,
@@ -166,7 +166,7 @@ NOTE(initial_value_provided_in_let_decl,none,
 ERROR(mutating_method_called_on_immutable_value,none,
       "mutating %select{method|property access|subscript|operator}1 %0 may not"
       " be used on immutable value '%2'",
-      (Identifier, unsigned, StringRef))
+      (DeclName, unsigned, StringRef))
 ERROR(immutable_value_passed_inout,none,
       "immutable value '%0' may not be passed inout",
       (StringRef))