From 12cfdee61bf6aff310e87240026b25db8eb72a1e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sat, 29 Sep 2012 10:33:54 +0200
Subject: [PATCH] AssignIf: Check into scopes recursively

---
 lib/checkassignif.cpp | 65 ++++++++++++++++++++++++++++---------------
 lib/checkassignif.h   |  7 +++++
 test/testassignif.cpp |  8 ++++++
 3 files changed, 58 insertions(+), 22 deletions(-)

diff --git a/lib/checkassignif.cpp b/lib/checkassignif.cpp
index deffba3ed..641a70693 100644
--- a/lib/checkassignif.cpp
+++ b/lib/checkassignif.cpp
@@ -51,32 +51,53 @@ void CheckAssignIf::assignIf()
             if (num < 0)
                 continue;
 
-            for (const Token *tok2 = tok->tokAt(4); tok2; tok2 = tok2->next()) {
-                if (tok2->str() == "(" || tok2->str() == "}" || tok2->str() == "=")
-                    break;
-                if (Token::Match(tok2, "if|while|for (")) {
-                    // parse condition
-                    const Token * const end = tok2->next()->link();
-                    for (; tok2 != end; tok2 = tok2->next()) {
-                        if (Token::Match(tok2, "[(,] &| %varid% [,)]", varid))
-                            break;
-                        if (Token::Match(tok2,"&&|%oror%|( %varid% %any% %num% &&|%oror%|)", varid)) {
-                            const Token *vartok = tok2->next();
-                            const std::string& op(vartok->strAt(1));
-                            const MathLib::bigint num2 = MathLib::toLongNumber(vartok->strAt(2));
-                            const std::string condition(vartok->str() + op + vartok->strAt(2));
-                            if (op == "==" && (num & num2) != ((bitop=='&') ? num2 : num))
-                                assignIfError(tok, tok2, condition, false);
-                            else if (op == "!=" && (num & num2) != ((bitop=='&') ? num2 : num))
-                                assignIfError(tok, tok2, condition, true);
-                        }
-                    }
-                }
-            }
+            assignIfParseScope(tok, tok->tokAt(4), varid, bitop, num);
         }
     }
 }
 
+/** parse scopes recursively */
+bool CheckAssignIf::assignIfParseScope(const Token * const assignTok,
+                                       const Token * const startTok,
+                                       const unsigned int varid,
+                                       const char bitop,
+                                       const MathLib::bigint num)
+{
+    for (const Token *tok2 = startTok; tok2; tok2 = tok2->next()) {
+        if (Token::Match(tok2, "[(,] &| %varid% [,)]"))
+            return true;
+        if (tok2->str() == "}")
+            return false;
+        if (Token::Match(tok2, "if (")) {
+            // parse condition
+            const Token * const end = tok2->next()->link();
+            for (; tok2 != end; tok2 = tok2->next()) {
+                if (Token::Match(tok2, "[(,] &| %varid% [,)]", varid)) {
+                    return true;
+                }
+                if (Token::Match(tok2,"&&|%oror%|( %varid% %any% %num% &&|%oror%|)", varid)) {
+                    const Token *vartok = tok2->next();
+                    const std::string& op(vartok->strAt(1));
+                    const MathLib::bigint num2 = MathLib::toLongNumber(vartok->strAt(2));
+                    const std::string condition(vartok->str() + op + vartok->strAt(2));
+                    if (op == "==" && (num & num2) != ((bitop=='&') ? num2 : num))
+                        assignIfError(assignTok, tok2, condition, false);
+                    else if (op == "!=" && (num & num2) != ((bitop=='&') ? num2 : num))
+                        assignIfError(assignTok, tok2, condition, true);
+                }
+            }
+
+            bool ret1 = assignIfParseScope(assignTok, end->tokAt(2), varid, bitop, num);
+            bool ret2 = false;
+            if (Token::simpleMatch(end->next()->link(), "} else {"))
+                ret2 = assignIfParseScope(assignTok, end->next()->link()->tokAt(3), varid, bitop, num);
+            if (ret1 || ret2)
+                return true;
+        }
+    }
+    return false;
+}
+
 void CheckAssignIf::assignIfError(const Token *tok1, const Token *tok2, const std::string &condition, bool result)
 {
     std::list<const Token *> locations;
diff --git a/lib/checkassignif.h b/lib/checkassignif.h
index a31745f7b..901e6dbe9 100644
--- a/lib/checkassignif.h
+++ b/lib/checkassignif.h
@@ -55,6 +55,13 @@ public:
     /** mismatching assignment / comparison */
     void assignIf();
 
+    /** parse scopes recursively */
+    bool assignIfParseScope(const Token * const assignTok,
+                            const Token * const startTok,
+                            const unsigned int varid,
+                            const char bitop,
+                            const MathLib::bigint num);
+
     /** mismatching lhs and rhs in comparison */
     void comparison();
 
diff --git a/test/testassignif.cpp b/test/testassignif.cpp
index 33fe6fc03..80f053d0d 100644
--- a/test/testassignif.cpp
+++ b/test/testassignif.cpp
@@ -105,6 +105,14 @@ private:
               "    if (setvalue(&y) && y != 8);\n"
               "}");
         ASSERT_EQUALS("", errout.str());
+
+        // recursive checking into scopes
+        check("void f(int x) {\n"
+              "    int y = x & 7;\n"
+              "    if (z) y=0;\n"
+              "    else if (y==8);\n" // always false
+              "}");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:4]: (style) Mismatching assignment and comparison, comparison 'y==8' is always false.\n", errout.str());
     }
 
     void compare() {