From cc7e05a5b0ff92021f49331e6e50ed98e12c0883 Mon Sep 17 00:00:00 2001
From: Greg Hewgill <greg@hewgill.com>
Date: Fri, 4 Mar 2011 19:26:48 +1300
Subject: [PATCH] fix case where fall through comment precedes preprocessor
 line

---
 lib/preprocessor.cpp | 33 +++++++++++++++++++++++----------
 test/testother.cpp   | 14 ++++++++++++++
 2 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/lib/preprocessor.cpp b/lib/preprocessor.cpp
index 2e8cd86c5..d93ddd6ab 100644
--- a/lib/preprocessor.cpp
+++ b/lib/preprocessor.cpp
@@ -326,6 +326,7 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
     unsigned int newlines = 0;
     std::ostringstream code;
     unsigned char previous = 0;
+    bool inPreprocessorLine = false;
     std::vector<std::string> suppressionIDs;
 
     for (std::string::size_type i = hasbom(str) ? 3U : 0U; i < str.length(); ++i)
@@ -370,6 +371,8 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
             // if there has been <backspace><newline> sequences, add extra newlines..
             if (ch == '\n')
             {
+                if (previous != '\\')
+                    inPreprocessorLine = false;
                 ++lineno;
                 if (newlines > 0)
                 {
@@ -449,25 +452,35 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
                 }
             }
         }
+        else if (ch == '#' && previous == '\n')
+        {
+            code << ch;
+            previous = ch;
+            inPreprocessorLine = true;
+        }
         else
         {
-            // Not whitespace and not a comment. Must be code here!
-            // Add any pending inline suppressions that have accumulated.
-            if (!suppressionIDs.empty())
+            if (!inPreprocessorLine)
             {
-                if (settings != NULL)
+                // Not whitespace, not a comment, and not preprocessor.
+                // Must be code here!
+                // Add any pending inline suppressions that have accumulated.
+                if (!suppressionIDs.empty())
                 {
-                    // Add the suppressions.
-                    for (size_t j(0); j < suppressionIDs.size(); ++j)
+                    if (settings != NULL)
                     {
-                        const std::string errmsg(settings->nomsg.addSuppression(suppressionIDs[j], filename, lineno));
-                        if (!errmsg.empty())
+                        // Add the suppressions.
+                        for (size_t j(0); j < suppressionIDs.size(); ++j)
                         {
-                            writeError(filename, lineno, _errorLogger, "cppcheckError", errmsg);
+                            const std::string errmsg(settings->nomsg.addSuppression(suppressionIDs[j], filename, lineno));
+                            if (!errmsg.empty())
+                            {
+                                writeError(filename, lineno, _errorLogger, "cppcheckError", errmsg);
+                            }
                         }
                     }
+                    suppressionIDs.clear();
                 }
-                suppressionIDs.clear();
             }
 
             // String or char constants..
diff --git a/test/testother.cpp b/test/testother.cpp
index a95d8f391..16aa5afc1 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -1414,6 +1414,20 @@ private:
         // (no pun intended).
         TODO_ASSERT_EQUALS("",
                            "[test.cpp:11]: (warning) Switch falls through case without comment\n", errout.str());
+
+        check_preprocess_suppress(
+            "void foo() {\n"
+            "    switch (a) {\n"
+            "    case 1:\n"
+            "#ifndef A\n"
+            "        g();\n"
+            "        // fall through\n"
+            "#endif\n"
+            "    case 2:\n"
+            "        break;\n"
+            "    }\n"
+            "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void selfAssignment()