[change-namespace] Fix a misplaced case when there is no trailing newline character at the end of the file.

[ioeric]

Thanks for the fix! :)

change-namespace/ChangeNamespace.cpp

110–112

return (SM.getLocForEndOfFile(LocInfo.first) == End) ? End : End.getLocWithOffset(1);

change-namespace/ChangeNamespace.cpp

SourceLocation getStartOfNextLine(SourceLocation Loc, const SourceManager &SM,
   // Lex from the start of the given location.
   Lexer Lex(SM.getLocForStartOfFile(LocInfo.first), LangOpts, File.begin(),
             TokBegin, File.end());
 
   llvm::SmallVector<char, 16> Line;
   // FIXME: this is a bit hacky to get ReadToEndOfLine work.
   Lex.setParsingPreprocessorDirective(true);
   Lex.ReadToEndOfLine(&Line);
-  // FIXME: should not +1 at EOF.
-  return Loc.getLocWithOffset(Line.size() + 1);
+  auto End = Loc.getLocWithOffset(Line.size());
+  if (SM.getLocForEndOfFile(LocInfo.first) == End)
+    return End;
+  return End.getLocWithOffset(1);
 }
 
 // Returns `R` with new range that refers to code after `Replaces` being
 // applied.
 tooling::Replacement
 getReplacementInChangedCode(const tooling::Replacements &Replaces,
                             const tooling::Replacement &R) {
   unsigned NewStart = Replaces.getShiftedCodePosition(R.getOffset());

unittests/change-namespace/ChangeNamespaceTests.cpp

std::string Expected =
       "namespace y {\n"
       "void f() { na::a_f(); na::static_f(); na::A::f(); }\n"
       "void g() { f(); na::A::g(); }\n"
       "}  // namespace y\n"
       "}  // namespace x\n";
   EXPECT_EQ(format(Expected), runChangeNamespaceOnCode(Code));
 }
 
+TEST_F(ChangeNamespaceTest, NoMisplaceAtEOF) {
+  std::string Code = "namespace na {\n"
+                     "namespace nb {\n"
+                     "class A;\n"
+                     "class B {};\n"
+                     "}"
+                     "}";
+  std::string Expected = "namespace na {\n"
+                         "namespace nb {\n"
+                         "class A;\n"
+                         "}\n"
+                         "}\n"
+                         "namespace x {\n"
+                         "namespace y {\n"
+                         "\n"
+                         "class B {};\n"
+                         "} // namespace y\n"
+                         "} // namespace x\n";
+  EXPECT_EQ(format(Expected), runChangeNamespaceOnCode(Code));
+}
+
 } // anonymous namespace
 } // namespace change_namespace
 } // namespace clang