Allow use of overloaded methods when using LoggerMessage

src/libraries/Microsoft.Extensions.Logging.Abstractions/gen/LoggerMessageGenerator.Emitter.cs

@@ -138,14 +138,14 @@ private void GenStruct(LoggerMethod lm, string nestedIndentation)
         {nestedIndentation}/// {s_generatedTypeSummary}
         {nestedIndentation}[{s_generatedCodeAttribute}]
         {nestedIndentation}[{s_editorBrowsableAttribute}]
-        {nestedIndentation}private readonly struct __{lm.Name}Struct : global::System.Collections.Generic.IReadOnlyList<global::System.Collections.Generic.KeyValuePair<string, object?>>
+        {nestedIndentation}private readonly struct __{lm.UniqueName}Struct : global::System.Collections.Generic.IReadOnlyList<global::System.Collections.Generic.KeyValuePair<string, object?>>
         {nestedIndentation}{{");
                 GenFields(lm, nestedIndentation);
 
                 if (lm.TemplateParameters.Count > 0)
                 {
                     _builder.Append($@"
-            {nestedIndentation}public __{lm.Name}Struct(");
+            {nestedIndentation}public __{lm.UniqueName}Struct(");
                     GenArguments(lm);
                     _builder.Append($@")
             {nestedIndentation}{{");
@@ -166,7 +166,7 @@ private void GenStruct(LoggerMethod lm, string nestedIndentation)
             {nestedIndentation}}}
 ");
                 _builder.Append($@"
-            {nestedIndentation}public static readonly global::System.Func<__{lm.Name}Struct, global::System.Exception?, string> Format = (state, ex) => state.ToString();
+            {nestedIndentation}public static readonly global::System.Func<__{lm.UniqueName}Struct, global::System.Exception?, string> Format = (state, ex) => state.ToString();
 
             {nestedIndentation}public int Count => {lm.TemplateParameters.Count + 1};
 
@@ -343,7 +343,7 @@ private void GenArguments(LoggerMethod lm)
 
             private void GenHolder(LoggerMethod lm)
             {
-                string typeName = $"__{lm.Name}Struct";
+                string typeName = $"__{lm.UniqueName}Struct";
 
                 _builder.Append($"new {typeName}(");
                 foreach (LoggerParameter p in lm.TemplateParameters)
@@ -375,7 +375,7 @@ private void GenLogMethod(LoggerMethod lm, string nestedIndentation)
 
                     GenDefineTypes(lm, brackets: false);
 
-                    _builder.Append($@"global::System.Exception?> __{lm.Name}Callback =
+                    _builder.Append($@"global::System.Exception?> __{lm.UniqueName}Callback =
             {nestedIndentation}global::Microsoft.Extensions.Logging.LoggerMessage.Define");
 
                     GenDefineTypes(lm, brackets: true);
@@ -404,7 +404,7 @@ private void GenLogMethod(LoggerMethod lm, string nestedIndentation)
                 if (UseLoggerMessageDefine(lm))
                 {
                     _builder.Append($@"
-            {nestedIndentation}{enabledCheckIndentation}__{lm.Name}Callback({logger}, ");
+            {nestedIndentation}{enabledCheckIndentation}__{lm.UniqueName}Callback({logger}, ");
 
                     GenCallbackArguments(lm);
 
@@ -420,7 +420,7 @@ private void GenLogMethod(LoggerMethod lm, string nestedIndentation)
                 GenHolder(lm);
                 _builder.Append($@",
                 {nestedIndentation}{enabledCheckIndentation}{exceptionArg},
-                {nestedIndentation}{enabledCheckIndentation}__{lm.Name}Struct.Format);");
+                {nestedIndentation}{enabledCheckIndentation}__{lm.UniqueName}Struct.Format);");
                 }
 
                 if (!lm.SkipEnabledCheck)

src/libraries/Microsoft.Extensions.Logging.Abstractions/gen/LoggerMessageGenerator.Parser.cs

@@ -510,6 +510,23 @@ bool IsAllowedKind(SyntaxKind kind) =>
 
                         if (lc != null)
                         {
+                            //once we've collected all methods for the given class, check for overloads
+                            //and provide unique names for logger methods
+                            var methods = new Dictionary<string, int>(lc.Methods.Count);
+                            foreach (LoggerMethod lm in lc.Methods)
+                            {
+                                if (methods.ContainsKey(lm.Name))
+                                {
+                                    int currentCount = methods[lm.Name];
+                                    lm.UniqueName = $"{lm.Name}{currentCount}";
+                                    methods[lm.Name] = currentCount + 1;
+                                }
+                                else
+                                {
+                                    lm.UniqueName = lm.Name;
+                                    methods[lm.Name] = 1; //start from 1
+                                }
+                            }
                             results.Add(lc);
                         }
                     }
@@ -693,6 +710,7 @@ internal class LoggerMethod
             public readonly Dictionary<string, string> TemplateMap = new(StringComparer.OrdinalIgnoreCase);
             public readonly List<string> TemplateList = new();
             public string Name = string.Empty;
+            public string UniqueName = string.Empty;
             public string Message = string.Empty;
             public int? Level;
             public int EventId;

src/libraries/Microsoft.Extensions.Logging.Abstractions/tests/Microsoft.Extensions.Logging.Generators.Tests/LoggerMessageGeneratedCodeTests.cs

@@ -498,6 +498,26 @@ public void TemplateTests()
 
         }
 
+        [Fact]
+        public void OverloadTests()
+        {
+            var logger = new MockLogger();
+
+            logger.Reset();
+            OverloadTestExtensions.M0(logger, 1);
+            Assert.Null(logger.LastException);
+            Assert.Equal($"{nameof(OverloadTestExtensions.M0)}1", logger.LastFormattedString);
+            Assert.Equal(LogLevel.Trace, logger.LastLogLevel);
+            Assert.Equal("M0", logger.LastEventId.Name);
+
+            logger.Reset();
+            OverloadTestExtensions.M0(logger, "string");
+            Assert.Null(logger.LastException);
+            Assert.Equal($"{nameof(OverloadTestExtensions.M0)}string", logger.LastFormattedString);
+            Assert.Equal(LogLevel.Trace, logger.LastLogLevel);
+            Assert.Equal("M0", logger.LastEventId.Name);
+        }
+
         private static void AssertLastState(MockLogger logger, params KeyValuePair<string, object?>[] expected)
         {
             var rol = (IReadOnlyList<KeyValuePair<string, object?>>)logger.LastState!;

src/libraries/Microsoft.Extensions.Logging.Abstractions/tests/Microsoft.Extensions.Logging.Generators.Tests/TestClasses/OverloadTestExtensions.cs

@@ -0,0 +1,14 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.Extensions.Logging.Generators.Tests.TestClasses
+{
+    internal static partial class OverloadTestExtensions
+    {
+        [LoggerMessage(EventId = 0, Level = LogLevel.Trace, Message = "M0{p0}")]
+        public static partial void M0(ILogger logger, int p0);
+
+        [LoggerMessage(EventId = 1, Level = LogLevel.Trace, Message = "M0{p0}")]
+        public static partial void M0(ILogger logger, string p0);
+    }
+}