Don't report inconsitencies if lifetimes match

src/CodeAnalysis.Tests/ConventionAnalyzerTests.cs

@@ -214,4 +214,58 @@ public static void Main()
 
         await test.RunAsync();
     }
+
+    [Fact]
+    public async Task NoWarnIfMultipleSameLifetime()
+    {
+        var test = new CSharpSourceGeneratorTest<IncrementalGenerator, DefaultVerifier>
+        {
+            TestBehaviors = TestBehaviors.SkipGeneratedSourcesCheck,
+            TestCode =
+            """
+            using System;
+            using Microsoft.Extensions.DependencyInjection;
+
+            public interface IRepository { }
+
+            [Service]
+            public class MyRepository : IRepository { }
+
+            public static class Program
+            {
+                public static void Main()
+                {
+                    var services = new ServiceCollection();
+                    services.AddServices(typeof(IRepository));
+                }
+            }
+            """,
+            TestState =
+            {
+                AnalyzerConfigFiles =
+                {
+                    ("/.editorconfig",
+                    """
+                    is_global = true
+                    build_property.AddServicesExtension = true
+                    """)
+                },
+                Sources =
+                {
+                    StaticGenerator.AddServicesExtension,
+                    StaticGenerator.ServiceAttribute,
+                    StaticGenerator.ServiceAttributeT,
+                },
+                ReferenceAssemblies = new ReferenceAssemblies(
+                    "net8.0",
+                    new PackageIdentity(
+                        "Microsoft.NETCore.App.Ref", "8.0.0"),
+                        Path.Combine("ref", "net8.0"))
+                    .AddPackages(ImmutableArray.Create(
+                        new PackageIdentity("Microsoft.Extensions.DependencyInjection", "8.0.0")))
+            },
+        };
+
+        await test.RunAsync();
+    }
 }

src/DependencyInjection.Tests/GenerationTests.cs

@@ -381,7 +381,9 @@ public class SmsNotificationService : INotificationService
 
 // Showcases that legacy generic Service<TKey> attribute still works
 [Service("email")]
+#pragma warning disable CS0618 // Type or member is obsolete
 [Service<string>("default")]
+#pragma warning restore CS0618 // Type or member is obsolete
 public class EmailNotificationService : INotificationService
 {
     public string Notify(string message) => $"[Email] {message}";

src/DependencyInjection/IncrementalGenerator.cs

@@ -283,14 +283,18 @@ void ReportInconsistencies(SourceProductionContext context, ImmutableArray<Servi
             // report if within the group, there are different lifetimes with the same key (or no key)
             foreach (var keyed in group.GroupBy(x => x.Key?.Value).Where(g => g.Count() > 1))
             {
-                var lifetimes = string.Join(", ", keyed.Select(x => x.Lifetime).Distinct()
-                    .Select(x => x switch { 0 => "Singleton", 1 => "Scoped", 2 => "Transient", _ => "Unknown" }));
+                var lifetimes = keyed.Select(x => x.Lifetime).Distinct()
+                    .Select(x => x switch { 0 => "Singleton", 1 => "Scoped", 2 => "Transient", _ => "Unknown" })
+                    .ToArray();
+
+                if (lifetimes.Length == 1)
+                    continue;
 
                 var location = keyed.Where(x => x.Location != null).FirstOrDefault()?.Location;
                 var otherLocations = keyed.Where(x => x.Location != null).Skip(1).Select(x => x.Location!);
 
                 context.ReportDiagnostic(Diagnostic.Create(AmbiguousLifetime,
-                    location, otherLocations, keyed.First().Type.ToDisplayString(), lifetimes));
+                    location, otherLocations, keyed.First().Type.ToDisplayString(), string.Join(", ", lifetimes)));
             }
         }
     }