From 764015774feaf922c1143000e766b7083cb75a9e Mon Sep 17 00:00:00 2001
From: Jacob Parker <jacob@solidangle.ca>
Date: Wed, 7 Aug 2024 11:54:37 -0400
Subject: [PATCH] Use more [NotNullWhen(..)]

---
 .../Extensions/Microsoft.CodeAnalysis.cs      | 22 ++++++-------------
 .../NUnit/CategoryAnalyzer.cs                 |  2 +-
 .../NUnit/ConfigTestSetupStringsAnalyzer.cs   |  4 ++--
 .../CustomTestServiceLocatorAnalyzer.cs       |  2 +-
 4 files changed, 11 insertions(+), 19 deletions(-)

diff --git a/src/D2L.CodeStyle.TestAnalyzers/Extensions/Microsoft.CodeAnalysis.cs b/src/D2L.CodeStyle.TestAnalyzers/Extensions/Microsoft.CodeAnalysis.cs
index 059370c2..404fa12e 100644
--- a/src/D2L.CodeStyle.TestAnalyzers/Extensions/Microsoft.CodeAnalysis.cs
+++ b/src/D2L.CodeStyle.TestAnalyzers/Extensions/Microsoft.CodeAnalysis.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Diagnostics.CodeAnalysis;
 using System.Text;
 using Microsoft.CodeAnalysis;
 
@@ -9,7 +10,9 @@ public static class RoslynExtensions {
 
 		// Copied from the non-test assembly because we do not reference it.
 
-		public static bool IsNullOrErrorType( this ITypeSymbol? symbol ) {
+		public static bool IsNullOrErrorType(
+			[NotNullWhen( false )] this ITypeSymbol? symbol
+		) {
 
 			if( symbol == null ) {
 				return true;
@@ -26,20 +29,9 @@ public static bool IsNullOrErrorType( this ITypeSymbol? symbol ) {
 			return false;
 		}
 
-		public static bool IsErrorType( this ITypeSymbol symbol ) {
-
-			if( symbol.Kind == SymbolKind.ErrorType ) {
-				return true;
-			}
-
-			if( symbol.TypeKind == TypeKind.Error ) {
-				return true;
-			}
-
-			return false;
-		}
-
-		public static bool IsNullOrErrorType( this ISymbol symbol ) {
+		public static bool IsNullOrErrorType(
+			[NotNullWhen( false )] this ISymbol? symbol
+		) {
 
 			if( symbol == null ) {
 				return true;
diff --git a/src/D2L.CodeStyle.TestAnalyzers/NUnit/CategoryAnalyzer.cs b/src/D2L.CodeStyle.TestAnalyzers/NUnit/CategoryAnalyzer.cs
index b5c5582c..27626a56 100644
--- a/src/D2L.CodeStyle.TestAnalyzers/NUnit/CategoryAnalyzer.cs
+++ b/src/D2L.CodeStyle.TestAnalyzers/NUnit/CategoryAnalyzer.cs
@@ -54,7 +54,7 @@ private static void OnCompilationStart( CompilationStartAnalysisContext context
 					context: ctx,
 					bannedCategories: bannedCategories,
 					types: types,
-					syntax: (ctx.Node as MethodDeclarationSyntax)!
+					syntax: (MethodDeclarationSyntax)ctx.Node
 				),
 				SyntaxKind.MethodDeclaration
 			);
diff --git a/src/D2L.CodeStyle.TestAnalyzers/NUnit/ConfigTestSetupStringsAnalyzer.cs b/src/D2L.CodeStyle.TestAnalyzers/NUnit/ConfigTestSetupStringsAnalyzer.cs
index 6828a5c6..d0b45710 100644
--- a/src/D2L.CodeStyle.TestAnalyzers/NUnit/ConfigTestSetupStringsAnalyzer.cs
+++ b/src/D2L.CodeStyle.TestAnalyzers/NUnit/ConfigTestSetupStringsAnalyzer.cs
@@ -30,7 +30,7 @@ private static void Register( CompilationStartAnalysisContext context ) {
 			INamedTypeSymbol? attributeType =
 				context.Compilation.GetTypeByMetadataName( AttributeTypeName );
 
-			if( attributeType == null || attributeType.IsErrorType() ) {
+			if( attributeType.IsNullOrErrorType() ) {
 				return;
 			}
 
@@ -78,7 +78,7 @@ INamedTypeSymbol attributeType
 					.GetSymbolInfo( attribute, context.CancellationToken )
 					.Symbol;
 
-				if( symbol == null || symbol.Kind == SymbolKind.ErrorType ) {
+				if( symbol.IsNullOrErrorType() ) {
 					continue;
 				}
 
diff --git a/src/D2L.CodeStyle.TestAnalyzers/ServiceLocator/CustomTestServiceLocatorAnalyzer.cs b/src/D2L.CodeStyle.TestAnalyzers/ServiceLocator/CustomTestServiceLocatorAnalyzer.cs
index c07cc0a5..61e6c8ca 100644
--- a/src/D2L.CodeStyle.TestAnalyzers/ServiceLocator/CustomTestServiceLocatorAnalyzer.cs
+++ b/src/D2L.CodeStyle.TestAnalyzers/ServiceLocator/CustomTestServiceLocatorAnalyzer.cs
@@ -31,7 +31,7 @@ CompilationStartAnalysisContext context
 			INamedTypeSymbol? factoryType = context.Compilation
 				.GetTypeByMetadataName( TestServiceLocatorFactoryType );
 
-			if( factoryType == null || factoryType.IsErrorType() ) {
+			if( factoryType.IsNullOrErrorType() ) {
 				return;
 			}