refactor the parsing logic for "x.y" to detangle it a bit, NFC.

lib/Parse/ParseExpr.cpp

@@ -1250,24 +1250,51 @@ ParserResult<Expr> Parser::parseExprPostfix(Diag<> ID, bool isExprBasic) {
     // Check for a .foo suffix.
     SourceLoc TokLoc = Tok.getLoc();
     if (consumeIf(tok::period) || consumeIf(tok::period_prefix)) {
-      // Non-identifier cases.
+
-      if (Tok.isNot(tok::identifier) && Tok.isNot(tok::integer_literal) &&
+      // Handle "x.42" - a tuple index.
-          Tok.isNot(tok::kw_init)) {
+      if (Tok.is(tok::integer_literal)) {
-        // A metatype expr.
+        DeclName name = Context.getIdentifier(Tok.getText());
-        if (Tok.is(tok::kw_dynamicType)) {
+        SourceLoc nameLoc = consumeToken(tok::integer_literal);
-          Result = makeParserResult(
+        
-            new (Context) DynamicTypeExpr(Result.get(), consumeToken(),
+        // Don't allow '.<integer literal>' following a numeric literal
-                                       Type()));
+        // expression.
+        if (Result.isNonNull() && isa<NumberLiteralExpr>(Result.get())) {
+          diagnose(nameLoc, diag::numeric_literal_numeric_member)
+            .highlight(Result.get()->getSourceRange());
           continue;
         }
         
-        // A '.self' expr.
+        Result = makeParserResult(
+            new (Context) UnresolvedDotExpr(Result.get(), TokLoc, name,
+                                            DeclNameLoc(nameLoc),
+                                            /*Implicit=*/false));
+        continue;
+      }
+
+      // Handle "x.dynamicType" - A metatype expr.
+      if (Tok.is(tok::kw_dynamicType)) {
+        Result = makeParserResult(
+          new (Context) DynamicTypeExpr(Result.get(), consumeToken(), Type()));
+        continue;
+      }
+
+      // Handle "x.self" expr.
       if (Tok.is(tok::kw_self)) {
         Result = makeParserResult(
           new (Context) DotSelfExpr(Result.get(), TokLoc, consumeToken()));
         continue;
       }
       
+      // Handle "x.<tab>" for code completion.
+      if (Tok.is(tok::code_complete)) {
+        if (CodeCompletion && Result.isNonNull())
+          CodeCompletion->completeDotExpr(Result.get(), /*DotLoc=*/TokLoc);
+        // Eat the code completion token because we handled it.
+        consumeToken(tok::code_complete);
+        Result.setHasCodeCompletion();
+        return Result;
+      }
+      
       // If we have '.<keyword><code_complete>', try to recover by creating
       // an identifier with the same spelling as the keyword.
       if (Tok.isKeyword() && peekToken().is(tok::code_complete)) {
@@ -1279,34 +1306,14 @@ ParserResult<Expr> Parser::parseExprPostfix(Diag<> ID, bool isExprBasic) {
         consumeToken();
       }
 
-        if (Tok.is(tok::code_complete)) {
+      // Non-identifier cases.
-          if (CodeCompletion && Result.isNonNull())
+      if (Tok.isNot(tok::identifier, tok::kw_init)) {
-            CodeCompletion->completeDotExpr(Result.get(), /*DotLoc=*/TokLoc);
-          // Eat the code completion token because we handled it.
-          consumeToken(tok::code_complete);
-          Result.setHasCodeCompletion();
-          return Result;
-        }
         checkForInputIncomplete();
         diagnose(Tok, diag::expected_member_name);
         return nullptr;
       }
 
-      // Don't allow '.<integer literal>' following a numeric literal
+      assert(Tok.isAny(tok::identifier, tok::kw_init));
-      // expression.
-      if (Tok.is(tok::integer_literal) && Result.isNonNull() &&
-          (isa<FloatLiteralExpr>(Result.get()) ||
-           isa<IntegerLiteralExpr>(Result.get()))) {
-        diagnose(Tok, diag::numeric_literal_numeric_member)
-          .highlight(Result.get()->getSourceRange());
-        consumeToken();
-        continue;
-      }
-
-      if (Result.isParseError())
-        continue;
-
-      if (Tok.isAny(tok::identifier, tok::kw_init)) {
       DeclNameLoc NameLoc;
       DeclName Name = parseUnqualifiedDeclName(/*allowInit=*/true,
                                                NameLoc,
@@ -1332,14 +1339,6 @@ ParserResult<Expr> Parser::parseExprPostfix(Diag<> ID, bool isExprBasic) {
                    Result.get(), LAngleLoc, Context.AllocateCopy(locArgs),
                    RAngleLoc));
       }
-      } else {
-        DeclName name = Context.getIdentifier(Tok.getText());
-        SourceLoc nameLoc = consumeToken(tok::integer_literal);
-        Result = makeParserResult(
-            new (Context) UnresolvedDotExpr(Result.get(), TokLoc, name,
-                                            DeclNameLoc(nameLoc),
-                                            /*Implicit=*/false));
-      }
 
       // If there is an expr-call-suffix, parse it and form a call.
       if (Tok.isFollowingLParen())