Skip assignment nullability warning in error case (#61895)

dotnet · Jun 17, 2022 · 2e3d609 · 2e3d609
1 parent 92b69bf
commit 2e3d609
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Showing 2 changed files with 27 additions and 7 deletions.
diff --git a/src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs b/src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs
@@ -8083,7 +8083,7 @@ private TypeWithState VisitConversion(
 
             TypeWithState resultType = calculateResultType(targetTypeWithNullability, fromExplicitCast, resultState, isSuppressed, targetType);
 
-            if (operandType.Type?.IsErrorType() != true && !targetType.IsErrorType())
+            if (!conversionOperand.HasErrors && !targetType.IsErrorType())
             {
                 // Need to report all warnings that apply since the warnings can be suppressed individually.
                 if (reportTopLevelWarnings)

diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs
@@ -2646,18 +2646,12 @@ static void M(C<string> x)
                 // (6,26): error CS0208: Cannot take the address of, get the size of, or declare a pointer to a managed type ('C<string>')
                 //         C<string?>* y1 = &x;
                 Diagnostic(ErrorCode.ERR_ManagedAddr, "&x").WithArguments("C<string>").WithLocation(6, 26),
-                // (6,26): warning CS8619: Nullability of reference types in value of type 'C<string>*' doesn't match target type 'C<string?>*'.
-                //         C<string?>* y1 = &x;
-                Diagnostic(ErrorCode.WRN_NullabilityMismatchInAssignment, "&x").WithArguments("C<string>*", "C<string?>*").WithLocation(6, 26),
                 // (7,9): error CS0208: Cannot take the address of, get the size of, or declare a pointer to a managed type ('C<string?>')
                 //         C<string?>* y2 = &x!;
                 Diagnostic(ErrorCode.ERR_ManagedAddr, "C<string?>*").WithArguments("C<string?>").WithLocation(7, 9),
                 // (7,26): error CS0208: Cannot take the address of, get the size of, or declare a pointer to a managed type ('C<string>')
                 //         C<string?>* y2 = &x!;
                 Diagnostic(ErrorCode.ERR_ManagedAddr, "&x!").WithArguments("C<string>").WithLocation(7, 26),
-                // (7,26): warning CS8619: Nullability of reference types in value of type 'C<string>*' doesn't match target type 'C<string?>*'.
-                //         C<string?>* y2 = &x!;
-                Diagnostic(ErrorCode.WRN_NullabilityMismatchInAssignment, "&x!").WithArguments("C<string>*", "C<string?>*").WithLocation(7, 26),
                 // (7,27): error CS8598: The suppression operator is not allowed in this context
                 //         C<string?>* y2 = &x!;
                 Diagnostic(ErrorCode.ERR_IllegalSuppression, "x").WithLocation(7, 27)
@@ -156369,5 +156363,31 @@ public static void M(C c1, C? c2)
                 Diagnostic(ErrorCode.WRN_NullableValueTypeMayBeNull, "c2").WithLocation(25, 13)
                 );
         }
+
+        [Fact, WorkItem(61462, "https://github.com/dotnet/roslyn/issues/61462")]
+        public void NoNullabilityWarningUnlessAssignmentConversionExists()
+        {
+            var comp = CreateCompilation("""
+#nullable enable
+
+public static class S
+{
+    public const string A = "a";
+}
+
+public class C
+{
+    public (string, string) M()
+    {
+        return ("a", S.B);
+    }
+}
+""");
+            comp.VerifyDiagnostics(
+                // (12,24): error CS0117: 'S' does not contain a definition for 'B'
+                //         return ("a", S.B);
+                Diagnostic(ErrorCode.ERR_NoSuchMember, "B").WithArguments("S", "B").WithLocation(12, 24)
+                );
+        }
     }
 }