From 54c3b8c0290609bf7c37a907c3928f761d7e79b1 Mon Sep 17 00:00:00 2001
From: Antonio Aversa <antonio.aversa@sonarsource.com>
Date: Fri, 31 Mar 2023 11:58:37 +0200
Subject: [PATCH] Honor null forgiving operator

---
 .../EmptyNullableValueAccessBase.cs           |  9 ++++--
 ...mptyNullableValueAccess.NullableContext.cs | 30 +++++++++----------
 2 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/analyzers/src/SonarAnalyzer.Common/SymbolicExecution/Roslyn/RuleChecks/EmptyNullableValueAccessBase.cs b/analyzers/src/SonarAnalyzer.Common/SymbolicExecution/Roslyn/RuleChecks/EmptyNullableValueAccessBase.cs
index a718bee5ca3..df48fb78bb6 100644
--- a/analyzers/src/SonarAnalyzer.Common/SymbolicExecution/Roslyn/RuleChecks/EmptyNullableValueAccessBase.cs
+++ b/analyzers/src/SonarAnalyzer.Common/SymbolicExecution/Roslyn/RuleChecks/EmptyNullableValueAccessBase.cs
@@ -34,7 +34,8 @@ protected override ProgramState PreProcessSimple(SymbolicContext context)
             && reference.Property.Name == nameof(Nullable<int>.Value)
             && reference.Instance is { } instance
             && instance.Type.IsNullableValueType()
-            && context.HasConstraint(instance, ObjectConstraint.Null))
+            && context.HasConstraint(instance, ObjectConstraint.Null)
+            && NoNullForgiving(reference.Instance))
         {
             ReportIssue(instance, instance.Syntax.ToString());
         }
@@ -42,11 +43,15 @@ protected override ProgramState PreProcessSimple(SymbolicContext context)
             && operationInstance.ToConversion() is var conversion
             && conversion.Operand.Type.IsNullableValueType()
             && conversion.Type.IsNonNullableValueType()
-            && context.HasConstraint(conversion.Operand, ObjectConstraint.Null))
+            && context.HasConstraint(conversion.Operand, ObjectConstraint.Null)
+            && NoNullForgiving(conversion.Operand))
         {
             ReportIssue(conversion.Operand, conversion.Operand.Syntax.ToString());
         }
 
         return context.State;
+
+        bool NoNullForgiving(IOperation reference) =>
+            SemanticModel.GetTypeInfo(reference.Syntax).Nullability().FlowState != NullableFlowState.NotNull;
     }
 }
diff --git a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/SymbolicExecution/Roslyn/EmptyNullableValueAccess.NullableContext.cs b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/SymbolicExecution/Roslyn/EmptyNullableValueAccess.NullableContext.cs
index e14353f904e..d70ad0fbd7c 100644
--- a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/SymbolicExecution/Roslyn/EmptyNullableValueAccess.NullableContext.cs
+++ b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/SymbolicExecution/Roslyn/EmptyNullableValueAccess.NullableContext.cs
@@ -7,42 +7,42 @@ class NullForgivingOperator
 {
     void Basics(int? i)
     {
-        _ = i!.Value;               // Compliant, unknown
+        _ = i!.Value;               // Compliant, user-asserted non-empty via bang
         i = SomeMethod();
-        _ = i!.Value;               // Compliant, unknown
+        _ = i!.Value;               // Compliant
 
         i = null;
-        _ = i!.Value;               // Noncompliant, empty
+        _ = i!.Value;               // Compliant
         i = new int?();
-        _ = i!.Value;               // Noncompliant, empty
+        _ = i!.Value;               // Compliant
         i = new Nullable<int>();
-        _ = i!.Value;               // Noncompliant, empty
+        _ = i!.Value;               // Compliant
 
         i = 42;
-        _ = i!.Value;               // Compliant, non-empty
+        _ = i!.Value;               // Compliant
     }
 
     void CastToValueType(int? i)
     {
-        _ = (int)i!;                // Compliant, unknown
+        _ = (int)i!;                // Compliant, user-asserted non-empty via bang
         i = SomeMethod();
-        _ = (int)i!;                // Compliant, unknown
+        _ = (int)i!;                // Compliant
 
         i = null;
-        _ = (int)i!;                // Noncompliant, empty
+        _ = (int)i!;                // Compliant
         i = new int?();
-        _ = (int)i!;                // Noncompliant, empty
+        _ = (int)i!;                // Compliant
         i = new Nullable<int>();
-        _ = (int)i!;                // Noncompliant, empty
+        _ = (int)i!;                // Compliant
     }
 
     void CastToNullableType(int? i)
     {
-        _ = ((int?)i)!.Value;       // Compliant, unknown
-        _ = (i as int?)!.Value;     // Compliant, unknown
+        _ = ((int?)i)!.Value;       // Compliant, user-asserted non-empty via bang
+        _ = (i as int?)!.Value;     // Compliant
 
-        _ = ((int?)null)!.Value;    // Noncompliant
-        _ = (null as int?)!.Value;  // Noncompliant
+        _ = ((int?)null)!.Value;    // Compliant
+        _ = (null as int?)!.Value;  // Compliant
     }
 
     static int? SomeMethod() => null;