implement SE-0071 - Allow (most) keywords in member references

Author: lattner

CHANGELOG.md

@@ -3,6 +3,10 @@ Note: This is in reverse chronological order, so newer entries are added to the
 Swift 3.0
 ---------
 
+* [SE-0071](https://github.com/apple/swift-evolution/blob/master/proposals/0071-member-keywords.md):
+  "Allow (most) keywords in member references" is implemented.  This allows the
+  use of members after a dot without backticks, e.g. "foo.default".
+
 * [SE-0057](https://github.com/apple/swift-evolution/blob/master/proposals/0057-importing-objc-generics.md):
   Objective-C lightweight generic classes are now imported as generic types
   in Swift. Because Objective-C generics are not represented at runtime,

include/swift/Parse/Parser.h

@@ -1124,11 +1124,11 @@ class Parser {
   ///     identifier
   ///     identifier '(' ((identifier | '_') ':') + ')'
   ///
-  ///
-  /// \param allowInit Whether to allow 'init' for initializers.
+  /// \param afterDot Whether this identifier is coming after a period, which
+  /// enables '.init' and '.default' like expressions.
   /// \param loc Will be populated with the location of the name.
   /// \param diag The diagnostic to emit if this is not a name.
-  DeclName parseUnqualifiedDeclName(bool allowInit, DeclNameLoc &loc,
+  DeclName parseUnqualifiedDeclName(bool afterDot, DeclNameLoc &loc,
                                     const Diagnostic &diag);
 
   Expr *parseExprIdentifier();

lib/Parse/ParseExpr.cpp

@@ -685,9 +685,7 @@ ParserResult<Expr> Parser::parseExprSuper() {
     }
 
     DeclNameLoc nameLoc;
-    DeclName name = parseUnqualifiedDeclName(
-                      /*allowInit=*/true,
-                      nameLoc,
+    DeclName name = parseUnqualifiedDeclName(/*afterDot=*/true, nameLoc,
                       diag::expected_identifier_after_super_dot_expr);
     if (!name)
       return nullptr;
@@ -894,7 +892,7 @@ getMagicIdentifierLiteralKind(tok Kind) {
 ///
 ///   expr-dot:
 ///     expr-postfix '.' 'type'
-///     expr-postfix '.' identifier generic-args? expr-call-suffix?
+///     expr-postfix '.' (identifier|keyword) generic-args? expr-call-suffix?
 ///     expr-postfix '.' integer_literal
 ///
 ///   expr-subscript:
@@ -1109,7 +1107,7 @@ ParserResult<Expr> Parser::parseExprPostfix(Diag<> ID, bool isExprBasic) {
       return Result;
     }
 
-    Name = parseUnqualifiedDeclName(/*allowInit=*/true, NameLoc, 
+    Name = parseUnqualifiedDeclName(/*afterDot=*/true, NameLoc,
                                     diag::expected_identifier_after_dot_expr);
     if (!Name) return nullptr;
 
@@ -1307,17 +1305,9 @@ ParserResult<Expr> Parser::parseExprPostfix(Diag<> ID, bool isExprBasic) {
         Result.setHasCodeCompletion();
         return Result;
       }
- 
-      // Non-identifier cases.
-      if (Tok.isNot(tok::identifier, tok::kw_init)) {
-        checkForInputIncomplete();
-        diagnose(Tok, diag::expected_member_name);
-        return nullptr;
-      }
 
-      assert(Tok.isAny(tok::identifier, tok::kw_init));
       DeclNameLoc NameLoc;
-      DeclName Name = parseUnqualifiedDeclName(/*allowInit=*/true,
+      DeclName Name = parseUnqualifiedDeclName(/*allowDot=*/true,
                                                NameLoc,
                                                diag::expected_member_name);
       if (!Name) return nullptr;
@@ -1600,18 +1590,17 @@ void Parser::diagnoseEscapedArgumentLabel(const Token &tok) {
     .fixItRemoveChars(end.getAdvancedLoc(-1), end);
 }
 
-DeclName Parser::parseUnqualifiedDeclName(bool allowInit,
+DeclName Parser::parseUnqualifiedDeclName(bool afterDot,
                                           DeclNameLoc &loc,
                                           const Diagnostic &diag) {
   // Consume the base name.
-  Identifier baseName;
+  Identifier baseName = Context.getIdentifier(Tok.getText());
   SourceLoc baseNameLoc;
-  if (Tok.is(tok::kw_init) && allowInit) {
-    baseName = Context.Id_init;
-    baseNameLoc = consumeToken(tok::kw_init);
-  } else if (Tok.is(tok::identifier) || Tok.is(tok::kw_Self) ||
-             Tok.is(tok::kw_self)) {
+  if (Tok.is(tok::identifier) || Tok.is(tok::kw_Self) ||
+      Tok.is(tok::kw_self)) {
     baseNameLoc = consumeIdentifier(&baseName);
+  } else if (afterDot && Tok.isKeyword()) {
+    baseNameLoc = consumeToken();
   } else {
     checkForInputIncomplete();
     diagnose(Tok, diag);
@@ -1713,7 +1702,7 @@ Expr *Parser::parseExprIdentifier() {
 
   // Parse the unqualified-decl-name.
   DeclNameLoc loc;
-  DeclName name = parseUnqualifiedDeclName(/*allowInit=*/false, loc,
+  DeclName name = parseUnqualifiedDeclName(/*afterDot=*/false, loc,
                                            diag::expected_expr);
 
   SmallVector<TypeRepr*, 8> args;

test/IDE/complete_unresolved_members.swift

@@ -217,6 +217,12 @@ extension C7 {
 var cInst1 = C7()
 cInst1.extendedf1(.#^UNRESOLVED_26^#
 
+      
+// This #if works around:
+// <rdar://problem/26057202> Crash in code completion on invalid input
+#if false
+#endif
+      
 func f() -> SomeEnum1 {
   return .#^UNRESOLVED_27^#
 }

test/expr/delayed-ident/enum.swift

@@ -5,12 +5,15 @@ enum E1 {
   case First
   case Second(Int)
   case Third(Int, Double)
+  case `default`
 }
 
 var e1: E1 = .First
 e1 = .Second(5)
 e1 = .Third(5, 3.14159)
 
+e1 = .default  // SE-0071
+
 // Generic enumeration type
 enum E2<T> {
   case First

test/expr/postfix/dot/dot_keywords.swift

@@ -3,3 +3,38 @@
 let x: Int = 1
 let y: Int = x.self
 let int: Int.Type = Int.self
+
+
+// SE-0071 - Allow (most) keywords in member references
+// https://github.com/apple/swift-evolution/blob/master/proposals/0071-member-keywords.md
+
+struct SE0071Struct {
+  var `default` : Int
+}
+
+func f1(a : SE0071Struct) -> Int {
+  return a.default
+}
+
+func f2(a : SE0071Struct) -> Int {
+  return a.`default`
+}
+
+  
+enum SE0071Enum {
+  case `case`
+}
+
+func f2() -> SE0071Enum {
+  return .case
+}
+
+class SE0071Base {
+  func `default`() {}
+}
+
+class SE0071Derived : SE0071Base {
+  func zonk() {
+    super.default()
+  }
+}

test/expr/unary/selector/selector.swift

@@ -116,7 +116,5 @@ func testParseErrors3(_ c1: C1) {
 
 func testParseErrors4() {
   // Subscripts
-  _ = #selector(C1.subscript) // expected-error{{expected member name following '.'}}
-  // expected-error@-1{{consecutive statements on a line must be separated by ';'}}
-  // expected-error@-2{{expected '(' for subscript parameters}}
+  _ = #selector(C1.subscript) // expected-error{{type 'C1.Type' has no subscript members}}
 }