From 9578b72915305a0b0a2ceae1f0e6bb370b8da617 Mon Sep 17 00:00:00 2001
From: Owen Smith <owen@omsmith.ca>
Date: Fri, 16 Oct 2026 15:28:04 -0400
Subject: [PATCH] ConstantAttributeAnalzyer: fix an ArgumentNullException from
 throw expressions

---
 src/D2L.CodeStyle.Analyzers/D2L.CodeStyle.Analyzers.csproj    | 2 +-
 .../D2L.CodeStyle.TestAnalyzers.csproj                        | 2 +-
 .../ConstantAttributeAnalyzer.cs                              | 4 ++++
 .../Specs/ConstantAttributeAnalyzer.cs                        | 1 +
 4 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/D2L.CodeStyle.Analyzers/D2L.CodeStyle.Analyzers.csproj b/src/D2L.CodeStyle.Analyzers/D2L.CodeStyle.Analyzers.csproj
index a2962efb..471366c3 100644
--- a/src/D2L.CodeStyle.Analyzers/D2L.CodeStyle.Analyzers.csproj
+++ b/src/D2L.CodeStyle.Analyzers/D2L.CodeStyle.Analyzers.csproj
@@ -6,7 +6,7 @@
     <Title>D2L.CodeStyle.Analyzers</Title>
     <Product>D2L.CodeStyle</Product>
     <Description>D2L.CodeStyle analyzers</Description>
-    <Version>0.230.0</Version>
+    <Version>0.231.0</Version>
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <PackageProjectUrl>https://github.com/Brightspace/D2L.CodeStyle</PackageProjectUrl>
     <Authors>D2L</Authors>
diff --git a/src/D2L.CodeStyle.TestAnalyzers/D2L.CodeStyle.TestAnalyzers.csproj b/src/D2L.CodeStyle.TestAnalyzers/D2L.CodeStyle.TestAnalyzers.csproj
index f94b35e1..94d9d9c4 100644
--- a/src/D2L.CodeStyle.TestAnalyzers/D2L.CodeStyle.TestAnalyzers.csproj
+++ b/src/D2L.CodeStyle.TestAnalyzers/D2L.CodeStyle.TestAnalyzers.csproj
@@ -6,7 +6,7 @@
     <Title>D2L.CodeStyle.TestAnalyzers</Title>
     <Product>D2L.CodeStyle</Product>
     <Description>D2L.CodeStyle test analyzers</Description>
-    <Version>0.33.0</Version>
+    <Version>0.34.0</Version>
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <PackageProjectUrl>https://github.com/Brightspace/D2L.CodeStyle</PackageProjectUrl>
     <Authors>D2L</Authors>
diff --git a/src/Rules/D2L.CodeStyle.Analyzers.Rule.Constant/D2L.CodeStyle.Analyzers.Rule.Constant/ConstantAttributeAnalyzer.cs b/src/Rules/D2L.CodeStyle.Analyzers.Rule.Constant/D2L.CodeStyle.Analyzers.Rule.Constant/ConstantAttributeAnalyzer.cs
index b5b4a97a..3f3db4c5 100644
--- a/src/Rules/D2L.CodeStyle.Analyzers.Rule.Constant/D2L.CodeStyle.Analyzers.Rule.Constant/ConstantAttributeAnalyzer.cs
+++ b/src/Rules/D2L.CodeStyle.Analyzers.Rule.Constant/D2L.CodeStyle.Analyzers.Rule.Constant/ConstantAttributeAnalyzer.cs
@@ -190,6 +190,10 @@ private static void AnalyzeConversion(
 			ITypeSymbol targetType,
 			SyntaxNode diagnosticSyntax
 		) {
+			if( sourceType is null ) {
+				return;
+			}
+
 			Conversion conversion = context.Compilation.ClassifyConversion(
 				source: sourceType,
 				destination: targetType
diff --git a/tests/D2L.CodeStyle.Analyzers.Test/Specs/ConstantAttributeAnalyzer.cs b/tests/D2L.CodeStyle.Analyzers.Test/Specs/ConstantAttributeAnalyzer.cs
index 72b31270..c5dfa637 100644
--- a/tests/D2L.CodeStyle.Analyzers.Test/Specs/ConstantAttributeAnalyzer.cs
+++ b/tests/D2L.CodeStyle.Analyzers.Test/Specs/ConstantAttributeAnalyzer.cs
@@ -275,6 +275,7 @@ string untrusted
 			{ Types.ConstantStruct v = trusted; }
 			{ Types.ConstantStruct v = /* NonConstantPassedToConstantParameter(value) */ variable /**/; }
 			{ Types.ConstantStruct v = /* NonConstantPassedToConstantParameter(value) */ untrusted /**/; }
+			{ Types.ConstantStruct v = /* NonConstantPassedToConstantParameter(value) */ trusted ?? throw new ArgumentNullException( nameof( trusted ) ) /**/; }
 			{ (Types.ConstantStruct X, Types.ConstantStruct Y) v = (Constants.String, Constants.String); }
 			{ (Types.ConstantStruct X, Types.ConstantStruct Y) v = (Constants.String, trusted); }
 			{ (Types.ConstantStruct X, Types.ConstantStruct Y) v = (Constants.String, /* NonConstantPassedToConstantParameter(value) */ variable /**/); }