From 45a4369acd36f654589a160219e5f820d26cb3ea Mon Sep 17 00:00:00 2001
From: daver32 <38791383+daver32@users.noreply.github.com>
Date: Fri, 28 Jan 2022 12:01:02 +0100
Subject: [PATCH] Added prefixing for method params that have the same name as
 a C# keyword

---
 .../MethodGenerationTests.cs                  |  22 +++
 InterfaceGenerator/AutoInterfaceGenerator.cs  |  10 +-
 InterfaceGenerator/StringExtensions.cs        | 125 ++++++++++++++++++
 3 files changed, 156 insertions(+), 1 deletion(-)
 create mode 100644 InterfaceGenerator/StringExtensions.cs

diff --git a/InterfaceGenerator.Tests/MethodGenerationTests.cs b/InterfaceGenerator.Tests/MethodGenerationTests.cs
index 53aec89..34a55eb 100644
--- a/InterfaceGenerator.Tests/MethodGenerationTests.cs
+++ b/InterfaceGenerator.Tests/MethodGenerationTests.cs
@@ -31,6 +31,24 @@ namespace InterfaceGenerator.Tests
             _sut.VoidMethod();
         }
 
+        [Fact]
+        public void VoidMethodWithKeywordParam_IsImplemented()
+        {
+            var method = typeof(IMethodsTestService).GetMethod(
+                nameof(MethodsTestService.VoidMethodWithKeywordParam));
+            
+            method.Should().NotBeNull();
+            method.ReturnType.Should().Be(typeof(void));
+            
+            var parameters = method.GetParameters();
+            parameters.Select(x => x.ParameterType).Should().AllBeEquivalentTo(typeof(string));
+            parameters.Should().HaveCount(1);
+
+            parameters[0].Name.Should().Be("void");
+            
+            _sut.VoidMethodWithKeywordParam("");
+        }
+
         [Fact]
         public void VoidMethodWithParams_IsImplemented()
         {
@@ -257,6 +275,10 @@ namespace InterfaceGenerator.Tests
         public void VoidMethodWithParams(string a, string b)
         {
         }
+        
+        public void VoidMethodWithKeywordParam(string @void)
+        {
+        }
 
         public void VoidMethodWithOutParam(out string a)
         {
diff --git a/InterfaceGenerator/AutoInterfaceGenerator.cs b/InterfaceGenerator/AutoInterfaceGenerator.cs
index b06f513..8502761 100644
--- a/InterfaceGenerator/AutoInterfaceGenerator.cs
+++ b/InterfaceGenerator/AutoInterfaceGenerator.cs
@@ -323,8 +323,16 @@ namespace InterfaceGenerator
                     writer.Write("in ");
                     break;
             }
+            
+            writer.Write(param.Type);
+            writer.Write(" ");
 
-            writer.Write("{0} {1}", param.Type, param.Name);
+            if (StringExtensions.IsCSharpKeyword(param.Name))
+            {
+                writer.Write("@");
+            }
+            
+            writer.Write(param.Name);
 
             if (param.HasExplicitDefaultValue)
             {
diff --git a/InterfaceGenerator/StringExtensions.cs b/InterfaceGenerator/StringExtensions.cs
new file mode 100644
index 0000000..8859a69
--- /dev/null
+++ b/InterfaceGenerator/StringExtensions.cs
@@ -0,0 +1,125 @@
+namespace InterfaceGenerator
+{
+    internal static class StringExtensions
+    {
+        public static bool IsCSharpKeyword(string? name)
+        {
+            switch (name)
+            {
+                case "abstract":
+                case "add":
+                case "alias":
+                case "as":
+                case "ascending":
+                case "async":
+                case "await":
+                case "base":
+                case "bool":
+                case "break":
+                case "by":
+                case "byte":
+                case "case":
+                case "catch":
+                case "char":
+                case "checked":
+                case "class":
+                case "const":
+                case "continue":
+                case "decimal":
+                case "default":
+                case "delegate":
+                case "descending":
+                case "do":
+                case "double":
+                case "dynamic":
+                case "else":
+                case "enum":
+                case "equals":
+                case "event":
+                case "explicit":
+                case "extern":
+                case "false":
+                case "finally":
+                case "fixed":
+                case "float":
+                case "for":
+                case "foreach":
+                case "from":
+                case "get":
+                case "global":
+                case "goto":
+                // `group` is a contextual to linq queries that we don't generate
+                //case "group":
+                case "if":
+                case "implicit":
+                case "in":
+                case "int":
+                case "interface":
+                case "internal":
+                case "into":
+                case "is":
+                case "join":
+                case "let":
+                case "lock":
+                case "long":
+                case "nameof":
+                case "namespace":
+                case "new":
+                case "null":
+                case "object":
+                case "on":
+                case "operator":
+                // `orderby` is a contextual to linq queries that we don't generate
+                //case "orderby":
+                case "out":
+                case "override":
+                case "params":
+                case "partial":
+                case "private":
+                case "protected":
+                case "public":
+                case "readonly":
+                case "ref":
+                case "remove":
+                case "return":
+                case "sbyte":
+                case "sealed":
+                // `select` is a contextual to linq queries that we don't generate
+                // case "select":
+                case "set":
+                case "short":
+                case "sizeof":
+                case "stackalloc":
+                case "static":
+                case "string":
+                case "struct":
+                case "switch":
+                case "this":
+                case "throw":
+                case "true":
+                case "try":
+                case "typeof":
+                case "uint":
+                case "ulong":
+                case "unchecked":
+                case "unmanaged":
+                case "unsafe":
+                case "ushort":
+                case "using":
+                // `value` is a contextual to getters that we don't generate
+                // case "value":
+                case "var":
+                case "virtual":
+                case "void":
+                case "volatile":
+                case "when":
+                case "where":
+                case "while":
+                case "yield":
+                    return true;
+                default:
+                    return false;
+            }
+        }
+    }
+}
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