Add ability for detect what variable will be non null after if block.

Example:
    if (!ptr)
    {
        ptr1 = new data;
    }
    // here ptr1 always non null

3 files changed, 41 insertions, 0 deletions

diff --git a/src/analysis/collections.cpp b/src/analysis/collections.cpp
index 4fb861d..d8d9510 100644
--- a/src/analysis/collections.cpp
+++ b/src/analysis/collections.cpp
@@ -58,6 +58,20 @@ void addNeedCheckNullVars2(WalkItem &wi, WalkItem &wo)
     }
 }
 
+void removeNeedCheckNullVars2(WalkItem &wco, WalkItem &wi, WalkItem &wo)
+{
+    FOR_EACH (it, wi.knownNonNullVars)
+    {
+        // check what it presend in if condition like if (!it) and in else like if (it)
+        if (isIn(it, wco.checkedThenNullVars) &&
+            isIn(it, wco.checkedElseNonNullVars))
+        {
+            removeNeedCheckNullVarOnly(wo, it);
+            addNonNullVar(wo, it);
+        }
+    }
+}
+
 // remove one variable from null pointer checks
 void removeNeedCheckNullVar(WalkItem &wi, std::string str)
 {
@@ -379,6 +393,23 @@ void addKnownNonNullVarsWithLinked(WalkItem &wo, WalkItem &wi, std::set<std::str
     }
 }
 
+void addKnownNonNullVarWithLinked(WalkItem &wo, WalkItem &wi, const std::string &var)
+{
+    wo.knownNonNullVars.insert(var);
+    auto it2 = wi.linkedVars.find(var);
+    if (it2 == wi.linkedVars.end() &&
+        isIn(var, wi.linkedReverseVars))
+    {
+        wo.knownNonNullVars.insert(wi.linkedReverseVars[var]);
+        it2 = wi.linkedVars.find(wi.linkedReverseVars[var]);
+    }
+    if (it2 != wi.linkedVars.end())
+    {
+        const StringSet &linked = (*it2).second;
+        wo.knownNonNullVars.insert(linked.begin(), linked.end());
+    }
+}
+
 void removeVar(WalkItem &wi, const std::string &var)
 {
     wi.removeNullVars.insert(var);
diff --git a/src/analysis/collections.h b/src/analysis/collections.h
index a03cbe5..1e36bf0 100644
--- a/src/analysis/collections.h
+++ b/src/analysis/collections.h
@@ -86,6 +86,12 @@ namespace Analysis
     void enforceNeedCheckNullVars(WalkItem &wi);
 
     void removeLinkVarOnly(WalkItem &wi, const std::string &var);
+
+    void removeNeedCheckNullVars2(WalkItem &wco, WalkItem &wi, WalkItem &wo);
+
+    void addKnownNonNullVarWithLinked(WalkItem &wo, WalkItem &wi, const std::string &var);
+
+    void removeNeedCheckNullVarOnly(WalkItem &wi, const std::string &var);
 }
 
 #endif // ANALYSIS_COLLECTIONS_H
diff --git a/src/analysis/statement.cpp b/src/analysis/statement.cpp
index 5f1f95b..39c03d2 100644
--- a/src/analysis/statement.cpp
+++ b/src/analysis/statement.cpp
@@ -126,6 +126,7 @@ void analyseCondition(Node *node,
     else if (thenNode)
     {
         addNeedCheckNullVars2(wo2, wo);
+        removeNeedCheckNullVars2(wco, wo2, wo);
     }
     if (wo3.isReturned || wo3.isContinued)
     {
@@ -144,6 +145,7 @@ void analyseCondition(Node *node,
     else if (elseNode)
     {
         addNeedCheckNullVars2(wo3, wo);
+        removeNeedCheckNullVars2(wco, wo2, wo);
     }
     if ((wo2.isReturned || wo2.isContinued) && (wo3.isReturned || wo3.isContinued))
     {
@@ -242,6 +244,8 @@ void analyseWhileStmt(WhileStmtNode *node, const WalkItem &wi, WalkItem &wo)
         walkTree(condNode, wci, wco);
         command = oldCommand;
         Log::dumpWI(node, "wco2 ", wco);
+
+        removeNeedCheckNullVars2(wco, wo2, wo);
     }
 
     wo.isReturned = false;