From d0b6079a832d5c156af1e51274e09f28ee8677a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Tue, 10 Aug 2021 09:38:28 +0200
Subject: [PATCH] Fixed #10372 (Confusing message for
 compareValueOutOfTypeRangeError)

---
 lib/checkcondition.cpp |  4 +++-
 test/testcondition.cpp | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/lib/checkcondition.cpp b/lib/checkcondition.cpp
index 2e310e9c0..8b13fe127 100644
--- a/lib/checkcondition.cpp
+++ b/lib/checkcondition.cpp
@@ -1807,7 +1807,9 @@ void CheckCondition::checkCompareValueOutOfTypeRange()
 
                 const auto typeMinValue = (typeTok->valueType()->sign == ValueType::Sign::SIGNED) ? (-(1LL << (bits-1))) : 0;
                 const auto unsignedTypeMaxValue = (1LL << bits) - 1LL;
-                const auto typeMaxValue = (typeTok->valueType()->sign == ValueType::Sign::SIGNED) ? (unsignedTypeMaxValue / 2) : unsignedTypeMaxValue;
+                const auto typeMaxValue = (typeTok->valueType()->sign != ValueType::Sign::SIGNED || bits >= mSettings->int_bit) ?
+                                          unsignedTypeMaxValue : // unsigned type. signed int/long/long long; comparing sign bit is ok. i.e. 'i == 0xffffffff'
+                                          (unsignedTypeMaxValue / 2); // signed char/short
 
                 if (valueTok->getKnownIntValue() < typeMinValue)
                     compareValueOutOfTypeRangeError(valueTok, typeTok->valueType()->str(), valueTok->getKnownIntValue());
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index 075ae52a1..fbf7932f8 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -4439,6 +4439,32 @@ private:
               "  if (b == true) {}\n"
               "}", &settingsUnix64);
         ASSERT_EQUALS("", errout.str());
+
+        // #10372
+        check("void f(signed char x) {\n"
+              "  if (x == 0xff) {}\n"
+              "}", &settingsUnix64);
+        ASSERT_EQUALS("[test.cpp:2]: (style) Comparing expression of type 'signed char' against value 255. Condition is always true/false.\n", errout.str());
+
+        check("void f(short x) {\n"
+              "  if (x == 0xffff) {}\n"
+              "}", &settingsUnix64);
+        ASSERT_EQUALS("[test.cpp:2]: (style) Comparing expression of type 'signed short' against value 65535. Condition is always true/false.\n", errout.str());
+
+        check("void f(int x) {\n"
+              "  if (x == 0xffffffff) {}\n"
+              "}", &settingsUnix64);
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f(long x) {\n"
+              "  if (x == ~0L) {}\n"
+              "}", &settingsUnix64);
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f(long long x) {\n"
+              "  if (x == ~0LL) {}\n"
+              "}", &settingsUnix64);
+        ASSERT_EQUALS("", errout.str());
     }
 
     void knownConditionCast() { // #9976