Disable check for useless checks in second check in while condition.

This fix false positive in this example:
    while(ptr)
    {
        ...
    }

4 files changed, 22 insertions, 7 deletions

diff --git a/src/analysis/reports.cpp b/src/analysis/reports.cpp
index 5a46dfe..af5806b 100644
--- a/src/analysis/reports.cpp
+++ b/src/analysis/reports.cpp
@@ -19,6 +19,7 @@
 
 #include "analysis/reports.h"
 
+#include "command.h"
 #include "logger.h"
 
 #include "analysis/analysis.h"
@@ -46,6 +47,8 @@ bool checkForReport(Node *node,
 void reportUselessCheck(Node *node,
                         const std::string &var)
 {
+    if (!checkCommand(DetectUseless))
+        return;
     Log::warn(findBackLocation(node),
         "Useless variable check '%s'. It already was checked before",
         var);
diff --git a/src/analysis/statement.cpp b/src/analysis/statement.cpp
index a9bfef4..f8b428f 100644
--- a/src/analysis/statement.cpp
+++ b/src/analysis/statement.cpp
@@ -196,8 +196,6 @@ void analyseWhileStmt(WhileStmtNode *node, const WalkItem &wi, WalkItem &wo)
     WalkItem wi2 = wi;
     if (wco.cleanExpr)
         removeNeedCheckNullVarsSetAll(wi2, wco.checkedThenNonNullVars);
-//    wi2.needCheckNullVars.insert(wco.checkedThenNullVars.begin(),
-//        wco.checkedThenNullVars.end());
     addKnownNullVarsWithLinked(wi2, wco, wco.checkedThenNullVars);
     addKnownNonNullVarsWithLinked(wi2, wco, wco.checkedThenNonNullVars);
     wi2.needCheckNullVars = wi2.knownVars;
@@ -233,9 +231,12 @@ void analyseWhileStmt(WhileStmtNode *node, const WalkItem &wi, WalkItem &wo)
     {
         addNeedCheckNullVars2(wo2, wo);
 
-        wci = wo;
-        wco = wo;
+        const Command oldCommand = command;
+        disableCommand(DetectUseless);
+        wci = wo2;
+        wco = wo2;
         walkTree(condNode, wci, wco);
+        command = oldCommand;
         Log::dumpWI(node, "wco2 ", wco);
     }
 
diff --git a/src/command.h b/src/command.h
index a1ef995..7fb7386 100644
--- a/src/command.h
+++ b/src/command.h
@@ -21,6 +21,8 @@
 #define COMMAND_H
 
 #define checkCommand(val) ((command & Command::val) == Command::val)
+#define disableCommand(val) command = static_cast<Command>(static_cast<int>( \
+    command | Command::val) ^ static_cast<int>(Command::val))
 
 enum Command : int
 {
@@ -31,7 +33,8 @@ enum Command : int
     MemoryUsage        = 8,
     FindArgs           = 16,
     DetectNullPointers = 32,
-    DumpNullPointers   = 64
+    DumpNullPointers   = 64,
+    DetectUseless      = 128
 };
 
 extern Command command;
diff --git a/src/plugin.cpp b/src/plugin.cpp
index c1d9b18..cf611f5 100644
--- a/src/plugin.cpp
+++ b/src/plugin.cpp
@@ -40,6 +40,12 @@ Command command = Command::DetectNullPointers;
 std::map<tree, Node*> foundNodesMap;
 std::map<Node*, Node*> updateNodesMap;
 
+Command operator |(const Command &cmd1, const Command &cmd2)
+{
+    return static_cast<Command>(static_cast<int>(cmd1)
+        | static_cast<int>(cmd2));
+}
+
 static void pre_generic(void *gcc_data,
                         void *user_data A_UNUSED)
 {
@@ -94,11 +100,13 @@ int plugin_init (struct plugin_name_args *plugin_info,
             }
             else if (cmd == "detectnullpointers")
             {
-                command = Command::DetectNullPointers;
+                command = Command::DetectNullPointers |
+                    Command::DetectUseless;
             }
             else if (cmd == "dumpnullpointers")
             {
-                command = Command::DumpNullPointers;
+                command = Command::DumpNullPointers |
+                    Command::DetectUseless;
             }
             else
             {