Route parameters do not support BindAsync

Author: halter73

src/Framework/AspNetCoreAnalyzers/src/Analyzers/DiagnosticDescriptors.cs

@@ -161,10 +161,10 @@ internal static class DiagnosticDescriptors
         isEnabledByDefault: true,
         helpLinkUri: "https://aka.ms/aspnet/analyzers");
 
-    internal static readonly DiagnosticDescriptor RouteParameterComplexTypeIsNotParsableOrBindable = new(
+    internal static readonly DiagnosticDescriptor RouteParameterComplexTypeIsNotParsable = new(
         "ASP0020",
         "Complex types referenced by route parameters must be parsable",
-        "Parameter '{0}' of type {1} should define a bool TryParse(string, IFormatProvider, out {1}) method, or implement IParsable<{1}>, or define a ValueTask<{1}> BindAsync(HttpContext), or implement IBindableFromHttpContext<{1}>.",
+        "Parameter '{0}' of type {1} should define a bool TryParse(string, IFormatProvider, out {1}) method, or implement IParsable<{1}>.",
         "Usage",
         DiagnosticSeverity.Error,
         isEnabledByDefault: true,

src/Framework/AspNetCoreAnalyzers/src/Analyzers/RouteHandlers/DisallowNonParsableComplexTypesOnParameters.cs

@@ -68,14 +68,11 @@ private static void DisallowNonParsableComplexTypesOnParameters(
             if (IsRouteParameter(routeUsage, handlerDelegateParameter))
             {
                 var parsability = ParsabilityHelper.GetParsability(parameterTypeSymbol, wellKnownTypes);
-                var bindability = ParsabilityHelper.GetBindability(parameterTypeSymbol, wellKnownTypes);
 
-                if (!(parsability == Parsability.Parsable || bindability == Bindability.Bindable))
+                if (parsability != Parsability.Parsable)
                 {
-                    var descriptor = SelectDescriptor(parsability, bindability);
-
                     context.ReportDiagnostic(Diagnostic.Create(
-                        descriptor,
+                        DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsable,
                         location,
                         handlerDelegateParameter.Name,
                         parameterTypeSymbol.Name
@@ -103,10 +100,8 @@ static bool ReportFromAttributeDiagnostic(OperationAnalysisContext context, Well
             var parsability = ParsabilityHelper.GetParsability(parameterTypeSymbol, wellKnownTypes);
             if (parameter.HasAttributeImplementingInterface(fromMetadataInterfaceTypeSymbol) && parsability != Parsability.Parsable)
             {
-                var descriptor = SelectDescriptor(parsability, Bindability.NotBindable);
-
                 context.ReportDiagnostic(Diagnostic.Create(
-                    descriptor,
+                    DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsable,
                     location,
                     parameter.Name,
                     parameterTypeSymbol.Name
@@ -140,16 +135,5 @@ static bool ReportFromAttributeDiagnostic(OperationAnalysisContext context, Well
 
             return parameterTypeSymbol;
         }
-
-        static DiagnosticDescriptor SelectDescriptor(Parsability parsability, Bindability bindability)
-        {
-            // This abomination is used to take the parsability and bindability and together figure
-            // out what the most optimal diagnostic message is to give to our plucky user.
-            return (parsability, bindability) switch
-            {
-                { parsability: Parsability.NotParsable, bindability: Bindability.InvalidReturnType } => DiagnosticDescriptors.BindAsyncSignatureMustReturnValueTaskOfT,
-                _ => DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsableOrBindable
-            };
-        }
     }
 }

src/Framework/AspNetCoreAnalyzers/src/Analyzers/RouteHandlers/RouteHandlerAnalyzer.cs

@@ -25,7 +25,7 @@ public partial class RouteHandlerAnalyzer : DiagnosticAnalyzer
         DiagnosticDescriptors.DoNotReturnActionResultsFromRouteHandlers,
         DiagnosticDescriptors.DetectMisplacedLambdaAttribute,
         DiagnosticDescriptors.DetectMismatchedParameterOptionality,
-        DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsableOrBindable,
+        DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsable,
         DiagnosticDescriptors.BindAsyncSignatureMustReturnValueTaskOfT,
         DiagnosticDescriptors.AmbiguousRouteHandlerRoute,
         DiagnosticDescriptors.AtMostOneFromBodyAttribute

src/Framework/AspNetCoreAnalyzers/test/RouteHandlers/DisallowNonParsableComplexTypesOnParametersTest.cs

@@ -195,7 +195,7 @@ public class Customer
 }
 """;
 
-        var expectedDiagnostic = new DiagnosticResult(DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsableOrBindable)
+        var expectedDiagnostic = new DiagnosticResult(DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsable)
             .WithArguments("customer", "Customer")
             .WithLocation(0);
 
@@ -218,7 +218,7 @@ public class Customer
 }
 """;
 
-        var expectedDiagnostic = new DiagnosticResult(DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsableOrBindable)
+        var expectedDiagnostic = new DiagnosticResult(DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsable)
             .WithArguments("customer", "Customer")
             .WithLocation(0);
 
@@ -289,7 +289,7 @@ public static bool TryParse(string s, IFormatProvider provider, out Customer res
     }
 
     [Fact]
-    public async Task Route_Parameter_withBindAsyncMethodThatReturnsTask_of_T_Fails()
+    public async Task Route_Parameter_withBindAsyncMethod_Fails()
     {
         // Arrange
         var source = $$"""
@@ -301,14 +301,14 @@ public async Task Route_Parameter_withBindAsyncMethodThatReturnsTask_of_T_Fails(
 
 public class Customer
 {
-    public async static Task<Customer> BindAsync(HttpContext context)
+    public async static ValueTask<Customer> BindAsync(HttpContext context)
     {
         return new Customer();
     }
 }
 """;
 
-        var expectedDiagnostic = new DiagnosticResult(DiagnosticDescriptors.BindAsyncSignatureMustReturnValueTaskOfT)
+        var expectedDiagnostic = new DiagnosticResult(DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsable)
             .WithArguments("customer", "Customer")
             .WithLocation(0);
 
@@ -422,7 +422,7 @@ public static bool TryParse(string s, IFormatProvider provider, out Customer res
     }
 
     [Fact]
-    public async Task Route_Parameter_withHttpContextBindableComplexType_viaImplicitIBindableFromHttp_Works()
+    public async Task Route_Parameter_withHttpContextBindableComplexType_viaImplicitIBindableFromHttp_Fails()
     {
         // Arrange
         var source = $$"""
@@ -433,7 +433,7 @@ public async Task Route_Parameter_withHttpContextBindableComplexType_viaImplicit
 using Microsoft.AspNetCore.Http;
 
 var webApp = WebApplication.Create();
-webApp.MapGet("/customers/{customer}", (Customer customer) => {});
+webApp.MapGet("/customers/{customer}", ({|#0:Customer customer|}) => {});
 
 public class Customer : IBindableFromHttpContext<Customer>
 {
@@ -444,12 +444,16 @@ public class Customer : IBindableFromHttpContext<Customer>
 }
 """;
 
+        var expectedDiagnostic = new DiagnosticResult(DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsable)
+            .WithArguments("customer", "Customer")
+            .WithLocation(0);
+
         // Act
-        await VerifyCS.VerifyAnalyzerAsync(source);
+        await VerifyCS.VerifyAnalyzerAsync(source, expectedDiagnostic);
     }
 
     [Fact]
-    public async Task Route_Parameter_withHttpContextBindableComplexType_viaExplicitIBindableFromHttp_Works()
+    public async Task Route_Parameter_withHttpContextBindableComplexType_viaExplicitIBindableFromHttp_Fails()
     {
         // Arrange
         var source = $$"""
@@ -460,7 +464,7 @@ public async Task Route_Parameter_withHttpContextBindableComplexType_viaExplicit
 using Microsoft.AspNetCore.Http;
 
 var webApp = WebApplication.Create();
-webApp.MapGet("/customers/{customer}", (Customer customer) => {});
+webApp.MapGet("/customers/{customer}", ({|#0:Customer customer|}) => {});
 
 public class Customer : IBindableFromHttpContext<Customer>
 {
@@ -471,8 +475,12 @@ public class Customer : IBindableFromHttpContext<Customer>
 }
 """;
 
+        var expectedDiagnostic = new DiagnosticResult(DiagnosticDescriptors.RouteParameterComplexTypeIsNotParsable)
+            .WithArguments("customer", "Customer")
+            .WithLocation(0);
+
         // Act
-        await VerifyCS.VerifyAnalyzerAsync(source);
+        await VerifyCS.VerifyAnalyzerAsync(source, expectedDiagnostic);
     }
 
     [Fact]