From c8394909c007addadf7605f975f8789307736b33 Mon Sep 17 00:00:00 2001
From: Greg Hewgill <greg@hewgill.com>
Date: Sun, 6 Mar 2011 12:14:10 +1300
Subject: [PATCH] Relax detection of 'fall through' comment so it only adds a
 suppression if it immediately precedes 'case' or 'default'

---
 lib/preprocessor.cpp | 17 +++++++++++++++--
 test/testother.cpp   |  6 ++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/lib/preprocessor.cpp b/lib/preprocessor.cpp
index f98578a8c..25a43d806 100644
--- a/lib/preprocessor.cpp
+++ b/lib/preprocessor.cpp
@@ -331,6 +331,7 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
     unsigned char previous = 0;
     bool inPreprocessorLine = false;
     std::vector<std::string> suppressionIDs;
+    bool fallThroughComment = false;
 
     for (std::string::size_type i = hasbom(str) ? 3U : 0U; i < str.length(); ++i)
     {
@@ -412,7 +413,7 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
 
             if (_settings->_checkCodingStyle && isFallThroughComment(comment))
             {
-                suppressionIDs.push_back("switchCaseFallThrough");
+                fallThroughComment = true;
             }
 
             code << "\n";
@@ -439,7 +440,7 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
 
             if (_settings->_checkCodingStyle && isFallThroughComment(comment))
             {
-                suppressionIDs.push_back("switchCaseFallThrough");
+                fallThroughComment = true;
             }
 
             if (settings && settings->_inlineSuppressions)
@@ -467,6 +468,18 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
             {
                 // Not whitespace, not a comment, and not preprocessor.
                 // Must be code here!
+
+                // First check for a "fall through" comment match, but only
+                // add a suppression if the next token is 'case' or 'default'
+                if (fallThroughComment)
+                {
+                    std::string::size_type j = str.find_first_not_of("abcdefghijklmnopqrstuvwxyz", i);
+                    std::string tok = str.substr(i, j - i);
+                    if (tok == "case" || tok == "default")
+                        suppressionIDs.push_back("switchCaseFallThrough");
+                    fallThroughComment = false;
+                }
+
                 // Add any pending inline suppressions that have accumulated.
                 if (!suppressionIDs.empty())
                 {
diff --git a/test/testother.cpp b/test/testother.cpp
index e5dd1481b..00759ffac 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -1482,6 +1482,12 @@ private:
             "    }\n"
             "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check_preprocess_suppress(
+            "void foo() {\n"
+            "    // unrelated comment saying 'fall through'\n"
+            "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void selfAssignment()