feat: add diagnostic for nested ignores

src/Riok.Mapperly/AnalyzerReleases.Shipped.md

@@ -116,3 +116,12 @@ Rule ID | Category | Severity | Notes
 RMG048  | Mapper   | Error    | Used mapper members cannot be nullable
 RMG049  | Mapper   | Warning  | Source member is ignored and also explicitly mapped
 RMG050  | Mapper   | Warning  | Target member is ignored and also explicitly mapped
+
+## Release 3.3
+
+### New Rules
+
+Rule ID | Category | Severity | Notes
+--------|----------|----------|-------
+RMG051  | Mapper   | Warning  | Invalid ignore source member found, nested ignores are not supported
+RMG052  | Mapper   | Warning  | Invalid ignore target member found, nested ignores are not supported

src/Riok.Mapperly/Descriptors/MappingBodyBuilders/BuilderContext/MembersMappingBuilderContext.cs

@@ -140,6 +140,11 @@ private void AddUnmatchedIgnoredTargetMembersDiagnostics()
     {
         foreach (var notFoundIgnoredMember in _ignoredUnmatchedTargetMemberNames)
         {
+            if (notFoundIgnoredMember.Contains(StringMemberPath.PropertyAccessSeparator, StringComparison.Ordinal))
+            {
+                BuilderContext.ReportDiagnostic(DiagnosticDescriptors.NestedIgnoredTargetMember, notFoundIgnoredMember, Mapping.TargetType);
+                continue;
+            }
             BuilderContext.ReportDiagnostic(DiagnosticDescriptors.IgnoredTargetMemberNotFound, notFoundIgnoredMember, Mapping.TargetType);
         }
     }
@@ -148,6 +153,11 @@ private void AddUnmatchedIgnoredSourceMembersDiagnostics()
     {
         foreach (var notFoundIgnoredMember in _ignoredUnmatchedSourceMemberNames)
         {
+            if (notFoundIgnoredMember.Contains(StringMemberPath.PropertyAccessSeparator, StringComparison.Ordinal))
+            {
+                BuilderContext.ReportDiagnostic(DiagnosticDescriptors.NestedIgnoredSourceMember, notFoundIgnoredMember, Mapping.TargetType);
+                continue;
+            }
             BuilderContext.ReportDiagnostic(DiagnosticDescriptors.IgnoredSourceMemberNotFound, notFoundIgnoredMember, Mapping.SourceType);
         }
     }

src/Riok.Mapperly/Diagnostics/DiagnosticDescriptors.cs

@@ -446,4 +446,22 @@ public static class DiagnosticDescriptors
         DiagnosticSeverity.Warning,
         true
     );
+
+    public static readonly DiagnosticDescriptor NestedIgnoredSourceMember = new DiagnosticDescriptor(
+        "RMG051",
+        "Invalid ignore source member found, nested ignores are not supported",
+        "Invalid ignore source member {0} found for type {1}, nested ignores are not supported",
+        DiagnosticCategories.Mapper,
+        DiagnosticSeverity.Warning,
+        true
+    );
+
+    public static readonly DiagnosticDescriptor NestedIgnoredTargetMember = new DiagnosticDescriptor(
+        "RMG052",
+        "Invalid ignore target member found, nested ignores are not supported",
+        "Invalid ignore target member {0} found for type {1}, nested ignores are not supported",
+        DiagnosticCategories.Mapper,
+        DiagnosticSeverity.Warning,
+        true
+    );
 }

test/Riok.Mapperly.Tests/Mapping/ObjectPropertyIgnoreTest.cs

@@ -145,4 +145,28 @@ public void WithNotFoundIgnoredSourcePropertyShouldDiagnostic()
                 """
             );
     }
+
+    [Fact]
+    public void WithNestedIgnoredSourceAndTargetPropertyShouldDiagnostic()
+    {
+        var source = TestSourceBuilder.MapperWithBodyAndTypes(
+            "[MapperIgnoreSource(\"StringValue.Value\")] [MapperIgnoreTarget(\"StringValue.Value\")] partial B Map(A source);",
+            "class A { public string StringValue { get; set; } }",
+            "class B { public string StringValue { get; set; } }"
+        );
+
+        TestHelper
+            .GenerateMapper(source, TestHelperOptions.AllowDiagnostics)
+            .Should()
+            .HaveDiagnostic(DiagnosticDescriptors.NestedIgnoredSourceMember)
+            .HaveDiagnostic(DiagnosticDescriptors.NestedIgnoredTargetMember)
+            .HaveAssertedAllDiagnostics()
+            .HaveSingleMethodBody(
+                """
+                var target = new global::B();
+                target.StringValue = source.StringValue;
+                return target;
+                """
+            );
+    }
 }