C#: Remove redundant ConstantComparison.ql query.

Author: aschackmull

csharp/ql/integration-tests/posix/query-suite/csharp-code-quality-extended.qls.expected

@@ -65,7 +65,6 @@ ql/csharp/ql/src/Likely Bugs/Collections/ContainerLengthCmpOffByOne.ql
 ql/csharp/ql/src/Likely Bugs/Collections/ContainerSizeCmpZero.ql
 ql/csharp/ql/src/Likely Bugs/Collections/ReadOnlyContainer.ql
 ql/csharp/ql/src/Likely Bugs/Collections/WriteOnlyContainer.ql
-ql/csharp/ql/src/Likely Bugs/ConstantComparison.ql
 ql/csharp/ql/src/Likely Bugs/DangerousNonShortCircuitLogic.ql
 ql/csharp/ql/src/Likely Bugs/Dynamic/BadDynamicCall.ql
 ql/csharp/ql/src/Likely Bugs/EqualityCheckOnFloats.ql

csharp/ql/integration-tests/posix/query-suite/csharp-code-quality.qls.expected

@@ -38,7 +38,6 @@ ql/csharp/ql/src/Likely Bugs/Collections/ContainerLengthCmpOffByOne.ql
 ql/csharp/ql/src/Likely Bugs/Collections/ContainerSizeCmpZero.ql
 ql/csharp/ql/src/Likely Bugs/Collections/ReadOnlyContainer.ql
 ql/csharp/ql/src/Likely Bugs/Collections/WriteOnlyContainer.ql
-ql/csharp/ql/src/Likely Bugs/ConstantComparison.ql
 ql/csharp/ql/src/Likely Bugs/DangerousNonShortCircuitLogic.ql
 ql/csharp/ql/src/Likely Bugs/EqualityCheckOnFloats.ql
 ql/csharp/ql/src/Likely Bugs/EqualsArray.ql

csharp/ql/integration-tests/posix/query-suite/csharp-security-and-quality.qls.expected

@@ -69,7 +69,6 @@ ql/csharp/ql/src/Likely Bugs/Collections/ContainerLengthCmpOffByOne.ql
 ql/csharp/ql/src/Likely Bugs/Collections/ContainerSizeCmpZero.ql
 ql/csharp/ql/src/Likely Bugs/Collections/ReadOnlyContainer.ql
 ql/csharp/ql/src/Likely Bugs/Collections/WriteOnlyContainer.ql
-ql/csharp/ql/src/Likely Bugs/ConstantComparison.ql
 ql/csharp/ql/src/Likely Bugs/DangerousNonShortCircuitLogic.ql
 ql/csharp/ql/src/Likely Bugs/Dynamic/BadDynamicCall.ql
 ql/csharp/ql/src/Likely Bugs/EqualityCheckOnFloats.ql

csharp/ql/lib/semmle/code/csharp/commons/Constants.qll

@@ -4,19 +4,6 @@ import csharp
 private import semmle.code.csharp.commons.ComparisonTest
 private import semmle.code.csharp.commons.StructuralComparison as StructuralComparison
 
-pragma[noinline]
-private predicate isConstantCondition0(ControlFlow::Node cfn, boolean b) {
-  exists(cfn.getASuccessorByType(any(ControlFlow::BooleanSuccessor t | t.getValue() = b))) and
-  strictcount(ControlFlow::SuccessorType t | exists(cfn.getASuccessorByType(t))) = 1
-}
-
-/**
- * Holds if `e` is a condition that always evaluates to Boolean value `b`.
- */
-predicate isConstantCondition(Expr e, boolean b) {
-  forex(ControlFlow::Node cfn | cfn = e.getAControlFlowNode() | isConstantCondition0(cfn, b))
-}
-
 /**
  * Holds if comparison operation `co` is constant with the Boolean value `b`.
  * For example, the comparison `x > x` is constantly `false` in

csharp/ql/src/CSI/CompareIdenticalValues.ql

@@ -47,7 +47,6 @@ where
     not comparesIdenticalValuesNan(ct, _) and msg = "Comparison of identical values."
   ) and
   not isMutatingOperation(ct.getAnArgument().getAChild*()) and
-  not isConstantCondition(e, _) and // Avoid overlap with cs/constant-condition
-  not isConstantComparison(e, _) and // Avoid overlap with cs/constant-comparison
+  not isConstantComparison(e, _) and // Avoid overlap with cs/constant-condition
   not isExprInAssertion(e)
 select ct, msg

csharp/ql/src/Likely Bugs/ConstantComparison.cs

@@ -22,7 +22,6 @@
       - cs/comparison-of-identical-expressions
       - cs/complex-block
       - cs/complex-condition
-      - cs/constant-comparison
       - cs/constant-condition
       - cs/coupled-types
       - cs/dereferenced-value-is-always-null

csharp/ql/src/Likely Bugs/ConstantComparison.qhelp

@@ -16,16 +16,16 @@ void f()
     {
         bool good, bad;
 
-        bad = uintValue < 0;
-        bad = 0 > uintValue;
-        bad = 0 <= uintValue;
-        bad = uintValue >= 0;
+        bad = uintValue < 0; // $ Alert
+        bad = 0 > uintValue; // $ Alert
+        bad = 0 <= uintValue; // $ Alert
+        bad = uintValue >= 0; // $ Alert
 
-        bad = uintValue == -1;
-        bad = uintValue != -1;
-        bad = 256 == byteValue;
-        bad = 256 != byteValue;
-        bad = 1 != 0;
+        bad = uintValue == -1; // $ Alert
+        bad = uintValue != -1; // $ Alert
+        bad = 256 == byteValue; // $ Alert
+        bad = 256 != byteValue; // $ Alert
+        bad = 1 != 0; // $ Alert
 
         good = byteValue == 50;
         good = 50 != byteValue;
@@ -35,61 +35,61 @@ void f()
         good = intValue <= 1u;
         good = 1u >= intValue;
 
-        good = charValue >= '0';  // Regression
+        good = charValue >= '0';
         good = charValue < '0';
 
         // Test ranges
-        bad = charValue <= 65535;
-        bad = charValue >= 0;
+        bad = charValue <= 65535; // $ Alert
+        bad = charValue >= 0; // $ Alert
 
         good = charValue < 255;
         good = charValue > 0;
 
-        bad = byteValue >= byte.MinValue;
-        bad = byteValue <= byte.MaxValue;
+        bad = byteValue >= byte.MinValue; // $ Alert
+        bad = byteValue <= byte.MaxValue; // $ Alert
 
         good = byteValue > byte.MinValue;
         good = byteValue < byte.MaxValue;
 
-        bad = sbyteValue >= sbyte.MinValue;
-        bad = sbyteValue <= sbyte.MaxValue;
+        bad = sbyteValue >= sbyte.MinValue; // $ Alert
+        bad = sbyteValue <= sbyte.MaxValue; // $ Alert
 
         good = sbyteValue < sbyte.MaxValue;
         good = sbyteValue > sbyte.MinValue;
 
-        bad = shortValue >= short.MinValue;
-        bad = shortValue <= short.MaxValue;
+        bad = shortValue >= short.MinValue; // $ Alert
+        bad = shortValue <= short.MaxValue; // $ Alert
 
         good = shortValue > short.MinValue;
         good = shortValue < short.MaxValue;
 
-        bad = ushortValue >= ushort.MinValue;
-        bad = ushortValue <= ushort.MaxValue;
+        bad = ushortValue >= ushort.MinValue; // $ Alert
+        bad = ushortValue <= ushort.MaxValue; // $ Alert
 
         good = ushortValue > ushort.MinValue;
         good = ushortValue < ushort.MaxValue;
 
-        bad = intValue >= int.MinValue;
-        bad = intValue <= int.MaxValue;
+        bad = intValue >= int.MinValue; // $ Alert
+        bad = intValue <= int.MaxValue; // $ Alert
 
         good = intValue > int.MinValue;
         good = intValue < int.MaxValue;
 
-        bad = uintValue >= uint.MinValue;
+        bad = uintValue >= uint.MinValue; // $ Alert
         good = uintValue > uint.MinValue;
 
-        bad = ulongValue >= ulong.MinValue;
+        bad = ulongValue >= ulong.MinValue; // $ Alert
         good = ulongValue > ulong.MinValue;
 
         // Explicit casts can cause large values to be truncated or
         // to wrap into negative values.
         good = (sbyte)byteValue >= 0;
         good = (sbyte)byteValue == -1;
-        bad = (sbyte)byteValue > 127;
-        bad = (sbyte)byteValue > (sbyte)127;
+        bad = (sbyte)byteValue > 127; // $ Alert
+        bad = (sbyte)byteValue > (sbyte)127; // $ Alert
         good = (int)uintValue == -1;
         good = (sbyte)uintValue == -1;
-        bad = (sbyte)uintValue == 256;
+        bad = (sbyte)uintValue == 256; // $ Alert
 
         System.Diagnostics.Debug.Assert(ulongValue >= ulong.MinValue);  // GOOD
     }