[SyntaxParse] Fix AST source locations for function types

Base location for function type should include leading trivia.

Author: rintaro

lib/Parse/ParseType.cpp

@@ -362,7 +362,7 @@ Parser::TypeASTResult Parser::parseType(Diag<> MessageID,
     return SILBoxType;
   }
 
-  auto RealTypeLoc = Tok.getLoc();
+  auto RealTypeLoc = leadingTriviaLoc();
 
   ParserResult<TypeRepr> ty =
     parseTypeSimpleOrCompositionAST(MessageID, HandleCodeCompletion);

test/Parse/function_type_range.swift

@@ -0,0 +1,6 @@
+// Ensure that source range for the type does not go past the end of the buffer.
+// RUN: %target-swift-frontend -typecheck %s -dump-ast
+typealias Alias =
+
+
+() -> ()