vendor/clang/clang-trunk-r238337

1 files changed, 217 insertions, 75 deletions

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index 2a4721f2b3b7..10c68f9da617 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -109,10 +109,8 @@ struct ScalarEnumerationTraits<FormatStyle::NamespaceIndentationKind> {
   }
 };
 
-template <>
-struct ScalarEnumerationTraits<FormatStyle::PointerAlignmentStyle> {
-  static void enumeration(IO &IO,
-                          FormatStyle::PointerAlignmentStyle &Value) {
+template <> struct ScalarEnumerationTraits<FormatStyle::PointerAlignmentStyle> {
+  static void enumeration(IO &IO, FormatStyle::PointerAlignmentStyle &Value) {
     IO.enumCase(Value, "Middle", FormatStyle::PAS_Middle);
     IO.enumCase(Value, "Left", FormatStyle::PAS_Left);
     IO.enumCase(Value, "Right", FormatStyle::PAS_Right);
@@ -144,8 +142,8 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("Language", Style.Language);
 
     if (IO.outputting()) {
-      StringRef StylesArray[] = { "LLVM",    "Google", "Chromium",
-                                  "Mozilla", "WebKit", "GNU" };
+      StringRef StylesArray[] = {"LLVM",    "Google", "Chromium",
+                                 "Mozilla", "WebKit", "GNU"};
       ArrayRef<StringRef> Styles(StylesArray);
       for (size_t i = 0, e = Styles.size(); i < e; ++i) {
         StringRef StyleName(Styles[i]);
@@ -176,6 +174,7 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("AlignEscapedNewlinesLeft", Style.AlignEscapedNewlinesLeft);
     IO.mapOptional("AlignOperands", Style.AlignOperands);
     IO.mapOptional("AlignTrailingComments", Style.AlignTrailingComments);
+    IO.mapOptional("AlignConsecutiveAssignments", Style.AlignConsecutiveAssignments);
     IO.mapOptional("AllowAllParametersOfDeclarationOnNextLine",
                    Style.AllowAllParametersOfDeclarationOnNextLine);
     IO.mapOptional("AllowShortBlocksOnASingleLine",
@@ -273,7 +272,7 @@ template <> struct MappingTraits<FormatStyle> {
 // will be used to get default values for missing keys.
 // If the first element has no Language specified, it will be treated as the
 // default one for the following elements.
-template <> struct DocumentListTraits<std::vector<FormatStyle> > {
+template <> struct DocumentListTraits<std::vector<FormatStyle>> {
   static size_t size(IO &IO, std::vector<FormatStyle> &Seq) {
     return Seq.size();
   }
@@ -331,6 +330,7 @@ FormatStyle getLLVMStyle() {
   LLVMStyle.AlignAfterOpenBracket = true;
   LLVMStyle.AlignOperands = true;
   LLVMStyle.AlignTrailingComments = true;
+  LLVMStyle.AlignConsecutiveAssignments = false;
   LLVMStyle.AllowAllParametersOfDeclarationOnNextLine = true;
   LLVMStyle.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_All;
   LLVMStyle.AllowShortBlocksOnASingleLine = false;
@@ -600,10 +600,10 @@ public:
   FormatTokenLexer(SourceManager &SourceMgr, FileID ID, FormatStyle &Style,
                    encoding::Encoding Encoding)
       : FormatTok(nullptr), IsFirstToken(true), GreaterStashed(false),
-        Column(0), TrailingWhitespace(0), SourceMgr(SourceMgr), ID(ID),
-        Style(Style), IdentTable(getFormattingLangOpts(Style)),
-        Keywords(IdentTable), Encoding(Encoding), FirstInLineIndex(0),
-        FormattingDisabled(false) {
+        LessStashed(false), Column(0), TrailingWhitespace(0),
+        SourceMgr(SourceMgr), ID(ID), Style(Style),
+        IdentTable(getFormattingLangOpts(Style)), Keywords(IdentTable),
+        Encoding(Encoding), FirstInLineIndex(0), FormattingDisabled(false) {
     Lex.reset(new Lexer(ID, SourceMgr.getBuffer(ID), SourceMgr,
                         getFormattingLangOpts(Style)));
     Lex->SetKeepWhitespaceMode(true);
@@ -619,7 +619,7 @@ public:
     do {
       Tokens.push_back(getNextToken());
       tryMergePreviousTokens();
-      if (Tokens.back()->NewlinesBefore > 0)
+      if (Tokens.back()->NewlinesBefore > 0 || Tokens.back()->IsMultiline)
         FirstInLineIndex = Tokens.size() - 1;
     } while (Tokens.back()->Tok.isNot(tok::eof));
     return Tokens;
@@ -633,32 +633,62 @@ private:
       return;
     if (tryMergeConflictMarkers())
       return;
+    if (tryMergeLessLess())
+      return;
 
     if (Style.Language == FormatStyle::LK_JavaScript) {
       if (tryMergeJSRegexLiteral())
         return;
       if (tryMergeEscapeSequence())
         return;
+      if (tryMergeTemplateString())
+        return;
 
-      static tok::TokenKind JSIdentity[] = { tok::equalequal, tok::equal };
-      static tok::TokenKind JSNotIdentity[] = { tok::exclaimequal, tok::equal };
-      static tok::TokenKind JSShiftEqual[] = { tok::greater, tok::greater,
-                                               tok::greaterequal };
-      static tok::TokenKind JSRightArrow[] = { tok::equal, tok::greater };
-      // FIXME: We probably need to change token type to mimic operator with the
-      // correct priority.
-      if (tryMergeTokens(JSIdentity))
+      static const tok::TokenKind JSIdentity[] = {tok::equalequal, tok::equal};
+      static const tok::TokenKind JSNotIdentity[] = {tok::exclaimequal,
+                                                     tok::equal};
+      static const tok::TokenKind JSShiftEqual[] = {tok::greater, tok::greater,
+                                                    tok::greaterequal};
+      static const tok::TokenKind JSRightArrow[] = {tok::equal, tok::greater};
+      // FIXME: Investigate what token type gives the correct operator priority.
+      if (tryMergeTokens(JSIdentity, TT_BinaryOperator))
         return;
-      if (tryMergeTokens(JSNotIdentity))
+      if (tryMergeTokens(JSNotIdentity, TT_BinaryOperator))
         return;
-      if (tryMergeTokens(JSShiftEqual))
+      if (tryMergeTokens(JSShiftEqual, TT_BinaryOperator))
         return;
-      if (tryMergeTokens(JSRightArrow))
+      if (tryMergeTokens(JSRightArrow, TT_JsFatArrow))
         return;
     }
   }
 
-  bool tryMergeTokens(ArrayRef<tok::TokenKind> Kinds) {
+  bool tryMergeLessLess() {
+    // Merge X,less,less,Y into X,lessless,Y unless X or Y is less.
+    if (Tokens.size() < 3)
+      return false;
+
+    bool FourthTokenIsLess = false;
+    if (Tokens.size() > 3)
+      FourthTokenIsLess = (Tokens.end() - 4)[0]->is(tok::less);
+
+    auto First = Tokens.end() - 3;
+    if (First[2]->is(tok::less) || First[1]->isNot(tok::less) ||
+        First[0]->isNot(tok::less) || FourthTokenIsLess)
+      return false;
+
+    // Only merge if there currently is no whitespace between the two "<".
+    if (First[1]->WhitespaceRange.getBegin() !=
+        First[1]->WhitespaceRange.getEnd())
+      return false;
+
+    First[0]->Tok.setKind(tok::lessless);
+    First[0]->TokenText = "<<";
+    First[0]->ColumnWidth += 1;
+    Tokens.erase(Tokens.end() - 2);
+    return true;
+  }
+
+  bool tryMergeTokens(ArrayRef<tok::TokenKind> Kinds, TokenType NewType) {
     if (Tokens.size() < Kinds.size())
       return false;
 
@@ -668,8 +698,9 @@ private:
       return false;
     unsigned AddLength = 0;
     for (unsigned i = 1; i < Kinds.size(); ++i) {
-      if (!First[i]->is(Kinds[i]) || First[i]->WhitespaceRange.getBegin() !=
-                                         First[i]->WhitespaceRange.getEnd())
+      if (!First[i]->is(Kinds[i]) ||
+          First[i]->WhitespaceRange.getBegin() !=
+              First[i]->WhitespaceRange.getEnd())
         return false;
       AddLength += First[i]->TokenText.size();
     }
@@ -677,6 +708,7 @@ private:
     First[0]->TokenText = StringRef(First[0]->TokenText.data(),
                                     First[0]->TokenText.size() + AddLength);
     First[0]->ColumnWidth += AddLength;
+    First[0]->Type = NewType;
     return true;
   }
 
@@ -720,7 +752,7 @@ private:
     unsigned LastColumn = Tokens.back()->OriginalColumn;
     for (auto I = Tokens.rbegin() + 1, E = Tokens.rend(); I != E; ++I) {
       ++TokenCount;
-      if (I[0]->is(tok::slash) && I + 1 != E &&
+      if (I[0]->isOneOf(tok::slash, tok::slashequal) && I + 1 != E &&
           (I[1]->isOneOf(tok::l_paren, tok::semi, tok::l_brace, tok::r_brace,
                          tok::exclaim, tok::l_square, tok::colon, tok::comma,
                          tok::question, tok::kw_return) ||
@@ -745,6 +777,91 @@ private:
     return false;
   }
 
+  bool tryMergeTemplateString() {
+    if (Tokens.size() < 2)
+      return false;
+
+    FormatToken *EndBacktick = Tokens.back();
+    // Backticks get lexed as tok::unknown tokens. If a template string contains
+    // a comment start, it gets lexed as a tok::comment, or tok::unknown if
+    // unterminated.
+    if (!EndBacktick->isOneOf(tok::comment, tok::unknown))
+      return false;
+    size_t CommentBacktickPos = EndBacktick->TokenText.find('`');
+    // Unknown token that's not actually a backtick, or a comment that doesn't
+    // contain a backtick.
+    if (CommentBacktickPos == StringRef::npos)
+      return false;
+
+    unsigned TokenCount = 0;
+    bool IsMultiline = false;
+    unsigned EndColumnInFirstLine =
+        EndBacktick->OriginalColumn + EndBacktick->ColumnWidth;
+    for (auto I = Tokens.rbegin() + 1, E = Tokens.rend(); I != E; I++) {
+      ++TokenCount;
+      if (I[0]->NewlinesBefore > 0 || I[0]->IsMultiline)
+        IsMultiline = true;
+
+      // If there was a preceding template string, this must be the start of a
+      // template string, not the end.
+      if (I[0]->is(TT_TemplateString))
+        return false;
+
+      if (I[0]->isNot(tok::unknown) || I[0]->TokenText != "`") {
+        // Keep track of the rhs offset of the last token to wrap across lines -
+        // its the rhs offset of the first line of the template string, used to
+        // determine its width.
+        if (I[0]->IsMultiline)
+          EndColumnInFirstLine = I[0]->OriginalColumn + I[0]->ColumnWidth;
+        // If the token has newlines, the token before it (if it exists) is the
+        // rhs end of the previous line.
+        if (I[0]->NewlinesBefore > 0 && (I + 1 != E))
+          EndColumnInFirstLine = I[1]->OriginalColumn + I[1]->ColumnWidth;
+
+        continue;
+      }
+
+      Tokens.resize(Tokens.size() - TokenCount);
+      Tokens.back()->Type = TT_TemplateString;
+      const char *EndOffset =
+          EndBacktick->TokenText.data() + 1 + CommentBacktickPos;
+      if (CommentBacktickPos != 0) {
+        // If the backtick was not the first character (e.g. in a comment),
+        // re-lex after the backtick position.
+        SourceLocation Loc = EndBacktick->Tok.getLocation();
+        resetLexer(SourceMgr.getFileOffset(Loc) + CommentBacktickPos + 1);
+      }
+      Tokens.back()->TokenText =
+          StringRef(Tokens.back()->TokenText.data(),
+                    EndOffset - Tokens.back()->TokenText.data());
+
+      unsigned EndOriginalColumn = EndBacktick->OriginalColumn;
+      if (EndOriginalColumn == 0) {
+        SourceLocation Loc = EndBacktick->Tok.getLocation();
+        EndOriginalColumn = SourceMgr.getSpellingColumnNumber(Loc);
+      }
+      // If the ` is further down within the token (e.g. in a comment).
+      EndOriginalColumn += CommentBacktickPos;
+
+      if (IsMultiline) {
+        // ColumnWidth is from backtick to last token in line.
+        // LastLineColumnWidth is 0 to backtick.
+        // x = `some content
+        //     until here`;
+        Tokens.back()->ColumnWidth =
+            EndColumnInFirstLine - Tokens.back()->OriginalColumn;
+        Tokens.back()->LastLineColumnWidth = EndOriginalColumn;
+        Tokens.back()->IsMultiline = true;
+      } else {
+        // Token simply spans from start to end, +1 for the ` itself.
+        Tokens.back()->ColumnWidth =
+            EndOriginalColumn - Tokens.back()->OriginalColumn + 1;
+      }
+      return true;
+    }
+    return false;
+  }
+
   bool tryMerge_TMacro() {
     if (Tokens.size() < 4)
       return false;
@@ -772,6 +889,8 @@ private:
     String->OriginalColumn = Macro->OriginalColumn;
     String->ColumnWidth = encoding::columnWidthWithTabs(
         String->TokenText, String->OriginalColumn, Style.TabWidth, Encoding);
+    String->NewlinesBefore = Macro->NewlinesBefore;
+    String->HasUnescapedNewline = Macro->HasUnescapedNewline;
 
     Tokens.pop_back();
     Tokens.pop_back();
@@ -842,21 +961,33 @@ private:
     return false;
   }
 
+  FormatToken *getStashedToken() {
+    // Create a synthesized second '>' or '<' token.
+    Token Tok = FormatTok->Tok;
+    StringRef TokenText = FormatTok->TokenText;
+
+    unsigned OriginalColumn = FormatTok->OriginalColumn;
+    FormatTok = new (Allocator.Allocate()) FormatToken;
+    FormatTok->Tok = Tok;
+    SourceLocation TokLocation =
+        FormatTok->Tok.getLocation().getLocWithOffset(Tok.getLength() - 1);
+    FormatTok->Tok.setLocation(TokLocation);
+    FormatTok->WhitespaceRange = SourceRange(TokLocation, TokLocation);
+    FormatTok->TokenText = TokenText;
+    FormatTok->ColumnWidth = 1;
+    FormatTok->OriginalColumn = OriginalColumn + 1;
+
+    return FormatTok;
+  }
+
   FormatToken *getNextToken() {
     if (GreaterStashed) {
-      // Create a synthesized second '>' token.
-      // FIXME: Increment Column and set OriginalColumn.
-      Token Greater = FormatTok->Tok;
-      FormatTok = new (Allocator.Allocate()) FormatToken;
-      FormatTok->Tok = Greater;
-      SourceLocation GreaterLocation =
-          FormatTok->Tok.getLocation().getLocWithOffset(1);
-      FormatTok->WhitespaceRange =
-          SourceRange(GreaterLocation, GreaterLocation);
-      FormatTok->TokenText = ">";
-      FormatTok->ColumnWidth = 1;
       GreaterStashed = false;
-      return FormatTok;
+      return getStashedToken();
+    }
+    if (LessStashed) {
+      LessStashed = false;
+      return getStashedToken();
     }
 
     FormatTok = new (Allocator.Allocate()) FormatToken;
@@ -869,20 +1000,32 @@ private:
     // Consume and record whitespace until we find a significant token.
     unsigned WhitespaceLength = TrailingWhitespace;
     while (FormatTok->Tok.is(tok::unknown)) {
-      for (int i = 0, e = FormatTok->TokenText.size(); i != e; ++i) {
-        switch (FormatTok->TokenText[i]) {
+      StringRef Text = FormatTok->TokenText;
+      auto EscapesNewline = [&](int pos) {
+        // A '\r' here is just part of '\r\n'. Skip it.
+        if (pos >= 0 && Text[pos] == '\r')
+          --pos;
+        // See whether there is an odd number of '\' before this.
+        unsigned count = 0;
+        for (; pos >= 0; --pos, ++count)
+          if (Text[pos] != '\\')
+            break;
+        return count & 1;
+      };
+      // FIXME: This miscounts tok:unknown tokens that are not just
+      // whitespace, e.g. a '`' character.
+      for (int i = 0, e = Text.size(); i != e; ++i) {
+        switch (Text[i]) {
         case '\n':
           ++FormatTok->NewlinesBefore;
-          // FIXME: This is technically incorrect, as it could also
-          // be a literal backslash at the end of the line.
-          if (i == 0 || (FormatTok->TokenText[i - 1] != '\\' &&
-                         (FormatTok->TokenText[i - 1] != '\r' || i == 1 ||
-                          FormatTok->TokenText[i - 2] != '\\')))
-            FormatTok->HasUnescapedNewline = true;
+          FormatTok->HasUnescapedNewline = !EscapesNewline(i - 1);
           FormatTok->LastNewlineOffset = WhitespaceLength + i + 1;
           Column = 0;
           break;
         case '\r':
+          FormatTok->LastNewlineOffset = WhitespaceLength + i + 1;
+          Column = 0;
+          break;
         case '\f':
         case '\v':
           Column = 0;
@@ -894,8 +1037,7 @@ private:
           Column += Style.TabWidth - Column % Style.TabWidth;
           break;
         case '\\':
-          if (i + 1 == e || (FormatTok->TokenText[i + 1] != '\r' &&
-                             FormatTok->TokenText[i + 1] != '\n'))
+          if (i + 1 == e || (Text[i + 1] != '\r' && Text[i + 1] != '\n'))
             FormatTok->Type = TT_ImplicitStringLiteral;
           break;
         default:
@@ -920,6 +1062,7 @@ private:
            FormatTok->TokenText[1] == '\n') {
       ++FormatTok->NewlinesBefore;
       WhitespaceLength += 2;
+      FormatTok->LastNewlineOffset = 2;
       Column = 0;
       FormatTok->TokenText = FormatTok->TokenText.substr(2);
     }
@@ -948,6 +1091,10 @@ private:
       FormatTok->Tok.setKind(tok::greater);
       FormatTok->TokenText = FormatTok->TokenText.substr(0, 1);
       GreaterStashed = true;
+    } else if (FormatTok->Tok.is(tok::lessless)) {
+      FormatTok->Tok.setKind(tok::less);
+      FormatTok->TokenText = FormatTok->TokenText.substr(0, 1);
+      LessStashed = true;
     }
 
     // Now FormatTok is the next non-whitespace token.
@@ -975,16 +1122,16 @@ private:
       Column = FormatTok->LastLineColumnWidth;
     }
 
-    FormatTok->IsForEachMacro =
-        std::binary_search(ForEachMacros.begin(), ForEachMacros.end(),
-                           FormatTok->Tok.getIdentifierInfo());
+    if (std::find(ForEachMacros.begin(), ForEachMacros.end(),
+                  FormatTok->Tok.getIdentifierInfo()) != ForEachMacros.end())
+      FormatTok->Type = TT_ForEachMacro;
 
     return FormatTok;
   }
 
   FormatToken *FormatTok;
   bool IsFirstToken;
-  bool GreaterStashed;
+  bool GreaterStashed, LessStashed;
   unsigned Column;
   unsigned TrailingWhitespace;
   std::unique_ptr<Lexer> Lex;
@@ -1072,13 +1219,13 @@ public:
                        << "\n");
   }
 
-  tooling::Replacements format() {
+  tooling::Replacements format(bool *IncompleteFormat) {
     tooling::Replacements Result;
     FormatTokenLexer Tokens(SourceMgr, ID, Style, Encoding);
 
     UnwrappedLineParser Parser(Style, Tokens.getKeywords(), Tokens.lex(),
                                *this);
-    bool StructuralError = Parser.parse();
+    Parser.parse();
     assert(UnwrappedLines.rbegin()->empty());
     for (unsigned Run = 0, RunE = UnwrappedLines.size(); Run + 1 != RunE;
          ++Run) {
@@ -1088,7 +1235,7 @@ public:
         AnnotatedLines.push_back(new AnnotatedLine(UnwrappedLines[Run][i]));
       }
       tooling::Replacements RunResult =
-          format(AnnotatedLines, StructuralError, Tokens);
+          format(AnnotatedLines, Tokens, IncompleteFormat);
       DEBUG({
         llvm::dbgs() << "Replacements for run " << Run << ":\n";
         for (tooling::Replacements::iterator I = RunResult.begin(),
@@ -1107,7 +1254,7 @@ public:
   }
 
   tooling::Replacements format(SmallVectorImpl<AnnotatedLine *> &AnnotatedLines,
-                               bool StructuralError, FormatTokenLexer &Tokens) {
+                               FormatTokenLexer &Tokens, bool *IncompleteFormat) {
     TokenAnnotator Annotator(Style, Tokens.getKeywords());
     for (unsigned i = 0, e = AnnotatedLines.size(); i != e; ++i) {
       Annotator.annotate(*AnnotatedLines[i]);
@@ -1122,8 +1269,9 @@ public:
     ContinuationIndenter Indenter(Style, Tokens.getKeywords(), SourceMgr,
                                   Whitespaces, Encoding,
                                   BinPackInconclusiveFunctions);
-    UnwrappedLineFormatter Formatter(&Indenter, &Whitespaces, Style);
-    Formatter.format(AnnotatedLines, /*DryRun=*/false);
+    UnwrappedLineFormatter(&Indenter, &Whitespaces, Style, Tokens.getKeywords(),
+                           IncompleteFormat)
+        .format(AnnotatedLines);
     return Whitespaces.generateReplacements();
   }
 
@@ -1340,27 +1488,20 @@ private:
 
 } // end anonymous namespace
 
-tooling::Replacements reformat(const FormatStyle &Style, Lexer &Lex,
-                               SourceManager &SourceMgr,
-                               ArrayRef<CharSourceRange> Ranges) {
-  if (Style.DisableFormat)
-    return tooling::Replacements();
-  return reformat(Style, SourceMgr,
-                  SourceMgr.getFileID(Lex.getSourceLocation()), Ranges);
-}
-
 tooling::Replacements reformat(const FormatStyle &Style,
                                SourceManager &SourceMgr, FileID ID,
-                               ArrayRef<CharSourceRange> Ranges) {
+                               ArrayRef<CharSourceRange> Ranges,
+                               bool *IncompleteFormat) {
   if (Style.DisableFormat)
     return tooling::Replacements();
   Formatter formatter(Style, SourceMgr, ID, Ranges);
-  return formatter.format();
+  return formatter.format(IncompleteFormat);
 }
 
 tooling::Replacements reformat(const FormatStyle &Style, StringRef Code,
                                ArrayRef<tooling::Range> Ranges,
-                               StringRef FileName) {
+                               StringRef FileName,
+                               bool *IncompleteFormat) {
   if (Style.DisableFormat)
     return tooling::Replacements();
 
@@ -1383,7 +1524,7 @@ tooling::Replacements reformat(const FormatStyle &Style, StringRef Code,
     SourceLocation End = Start.getLocWithOffset(Range.getLength());
     CharRanges.push_back(CharSourceRange::getCharRange(Start, End));
   }
-  return reformat(Style, SourceMgr, ID, CharRanges);
+  return reformat(Style, SourceMgr, ID, CharRanges, IncompleteFormat);
 }
 
 LangOptions getFormattingLangOpts(const FormatStyle &Style) {
@@ -1392,12 +1533,12 @@ LangOptions getFormattingLangOpts(const FormatStyle &Style) {
   LangOpts.CPlusPlus11 = Style.Standard == FormatStyle::LS_Cpp03 ? 0 : 1;
   LangOpts.CPlusPlus14 = Style.Standard == FormatStyle::LS_Cpp03 ? 0 : 1;
   LangOpts.LineComment = 1;
-  bool AlternativeOperators = Style.Language != FormatStyle::LK_JavaScript &&
-                              Style.Language != FormatStyle::LK_Java;
+  bool AlternativeOperators = Style.Language == FormatStyle::LK_Cpp;
   LangOpts.CXXOperatorNames = AlternativeOperators ? 1 : 0;
   LangOpts.Bool = 1;
   LangOpts.ObjC1 = 1;
   LangOpts.ObjC2 = 1;
+  LangOpts.MicrosoftExt = 1; // To get kw___try, kw___finally.
   return LangOpts;
 }
 
@@ -1415,7 +1556,8 @@ const char *StyleOptionHelpDescription =
 static FormatStyle::LanguageKind getLanguageByFileName(StringRef FileName) {
   if (FileName.endswith(".java")) {
     return FormatStyle::LK_Java;
-  } else if (FileName.endswith_lower(".js")) {
+  } else if (FileName.endswith_lower(".js") || FileName.endswith_lower(".ts")) {
+    // JavaScript or TypeScript.
     return FormatStyle::LK_JavaScript;
   } else if (FileName.endswith_lower(".proto") ||
              FileName.endswith_lower(".protodevel")) {