Add test for getRawToken.

Author: bazuzi

clang/unittests/Lex/LexerTest.cpp

@@ -652,6 +652,38 @@ TEST_F(LexerTest, RawAndNormalLexSameForLineComments) {
   EXPECT_TRUE(ToksView.empty());
 }
 
+TEST_F(LexerTest, GetRawTokenOnEscapedNewLineChecksWhitespace) {
+  const llvm::StringLiteral Source = R"cc(
+  #define ONE \
+  1
+
+  int i = ONE;
+  )cc";
+  std::vector<Token> Toks =
+      CheckLex(Source, {tok::kw_int, tok::identifier, tok::equal,
+                        tok::numeric_constant, tok::semi});
+
+  // Set up by getting the raw token for the `1` in the macro definition.
+  const Token &OneExpanded = Toks[3];
+  Token Tok;
+  ASSERT_FALSE(
+      Lexer::getRawToken(OneExpanded.getLocation(), Tok, SourceMgr, LangOpts));
+  // The `ONE`.
+  ASSERT_EQ(Tok.getKind(), tok::raw_identifier);
+  ASSERT_FALSE(
+      Lexer::getRawToken(SourceMgr.getSpellingLoc(OneExpanded.getLocation()),
+                         Tok, SourceMgr, LangOpts));
+  // The `1` in the macro definition.
+  ASSERT_EQ(Tok.getKind(), tok::numeric_constant);
+
+  // Go back 4 characters: two spaces, one newline, and the backslash.
+  SourceLocation EscapedNewLineLoc = Tok.getLocation().getLocWithOffset(-4);
+  // Expect true (=failure) because the whitespace immediately after the
+  // escaped newline is not ignored.
+  EXPECT_TRUE(Lexer::getRawToken(EscapedNewLineLoc, Tok, SourceMgr, LangOpts,
+                                 /*IgnoreWhiteSpace=*/false));
+}
+
 TEST(LexerPreambleTest, PreambleBounds) {
   std::vector<std::string> Cases = {
       R"cc([[