diff --git a/src/Draco.Compiler.Tests/Semantics/AttributeTests.cs b/src/Draco.Compiler.Tests/Semantics/AttributeTests.cs
index b2c8cfbd5..aee64a4fd 100644
--- a/src/Draco.Compiler.Tests/Semantics/AttributeTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/AttributeTests.cs
@@ -103,7 +103,7 @@ public void AttributeIsWrittenIntoMetadata()
             FunctionDeclaration(
                 [Attribute(NameType("ObsoleteAttribute"), StringExpression("do not use this function"))],
                 "foo",
-                ParameterList(Parameter([Attribute(NameType("AllowNullAttribute"))], "arg", NameType("object"))),
+                ParameterList(NormalParameter([Attribute(NameType("AllowNullAttribute"))], "arg", NameType("object"))),
                 null,
                 BlockFunctionBody())));
 
@@ -132,7 +132,7 @@ public void AttributeReferencesTheSymbol()
             FunctionDeclaration(
                 [Attribute(NameType("ObsoleteAttribute"), StringExpression("do not use this function"))],
                 "foo",
-                ParameterList(Parameter([Attribute(NameType("AllowNullAttribute"))], "arg", NameType("object"))),
+                ParameterList(NormalParameter([Attribute(NameType("AllowNullAttribute"))], "arg", NameType("object"))),
                 null,
                 BlockFunctionBody())));
 
diff --git a/src/Draco.Compiler.Tests/Semantics/ControlFlowGraphTests.cs b/src/Draco.Compiler.Tests/Semantics/ControlFlowGraphTests.cs
index dcdcdd0c5..c1fb579f7 100644
--- a/src/Draco.Compiler.Tests/Semantics/ControlFlowGraphTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/ControlFlowGraphTests.cs
@@ -83,7 +83,7 @@ public async Task IfElse()
         var program = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "main",
-                ParameterList(Parameter("b", NameType("bool"))),
+                ParameterList(NormalParameter("b", NameType("bool"))),
                 null,
                 BlockFunctionBody(
                     ExpressionStatement(IfExpression(
@@ -149,7 +149,7 @@ public async Task EarlyReturn()
         var program = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "main",
-                ParameterList(Parameter("b", NameType("bool"))),
+                ParameterList(NormalParameter("b", NameType("bool"))),
                 null,
                 BlockFunctionBody(
                     ExpressionStatement(CallExpression(NameExpression("bar"))),
@@ -181,7 +181,7 @@ public async Task ConditionalGotoInAssignment()
         var program = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "main",
-                ParameterList(Parameter("b", NameType("bool"))),
+                ParameterList(NormalParameter("b", NameType("bool"))),
                 null,
                 BlockFunctionBody(
                     DeclarationStatement(VariableDeclaration(true, "x", null, IfExpression(
@@ -211,14 +211,14 @@ public async Task ForLoop()
         var program = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "main",
-                ParameterList(Parameter("s", GenericType(NameType("Array"), NameType("int32")))),
+                ParameterList(NormalParameter("s", GenericType(NameType("Array"), NameType("int32")))),
                 null,
                 BlockFunctionBody(
                     ExpressionStatement(ForExpression(
                         "i",
                         NameExpression("s"),
                         CallExpression(NameExpression("bar"), NameExpression("i")))))),
-            FunctionDeclaration("bar", ParameterList(Parameter("x", NameType("int32"))), null, BlockFunctionBody())));
+            FunctionDeclaration("bar", ParameterList(NormalParameter("x", NameType("int32"))), null, BlockFunctionBody())));
 
         // Act
         var cfg = FunctionToCfg(program);
@@ -243,10 +243,10 @@ public async Task ChainedComparison()
             FunctionDeclaration(
                 "foo",
                 ParameterList(
-                    Parameter("a", NameType("int32")),
-                    Parameter("b", NameType("int32")),
-                    Parameter("c", NameType("int32")),
-                    Parameter("d", NameType("int32"))),
+                    NormalParameter("a", NameType("int32")),
+                    NormalParameter("b", NameType("int32")),
+                    NormalParameter("c", NameType("int32")),
+                    NormalParameter("d", NameType("int32"))),
                 null,
                 InlineFunctionBody(RelationalExpression(
                     BlockExpression([ExpressionStatement(CallExpression(NameExpression("bar")))], NameExpression("a")),
diff --git a/src/Draco.Compiler.Tests/Semantics/DefiniteAssignmentTests.cs b/src/Draco.Compiler.Tests/Semantics/DefiniteAssignmentTests.cs
index 27999f55c..4192c5295 100644
--- a/src/Draco.Compiler.Tests/Semantics/DefiniteAssignmentTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/DefiniteAssignmentTests.cs
@@ -69,7 +69,7 @@ public void UseOfConditionallyAssignedVariable()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             null,
             BlockFunctionBody(
                 DeclarationStatement(VariableDeclaration(true, "x", NameType("int32"))),
@@ -100,7 +100,7 @@ public void UseOfConditionallyAssignedVariableOnBothBranches()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             null,
             BlockFunctionBody(
                 DeclarationStatement(VariableDeclaration(true, "x", NameType("int32"))),
@@ -130,7 +130,7 @@ public void JumpingMidAssignment()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             null,
             BlockFunctionBody(
                 DeclarationStatement(VariableDeclaration(true, "x", NameType("int32"), IfExpression(
@@ -189,7 +189,7 @@ public void UseVariableAssignedLater()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             null,
             BlockFunctionBody(
                 ExpressionStatement(WhileExpression(
diff --git a/src/Draco.Compiler.Tests/Semantics/LocalFunctionsTests.cs b/src/Draco.Compiler.Tests/Semantics/LocalFunctionsTests.cs
index 2339fb4f3..3958fe655 100644
--- a/src/Draco.Compiler.Tests/Semantics/LocalFunctionsTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/LocalFunctionsTests.cs
@@ -24,13 +24,13 @@ public void ParameterRedefinitionError()
             BlockFunctionBody(DeclarationStatement(FunctionDeclaration(
                 "bar",
                 ParameterList(
-                    Parameter("x", NameType("int32")),
-                    Parameter("x", NameType("int32"))),
+                    NormalParameter("x", NameType("int32")),
+                    NormalParameter("x", NameType("int32"))),
                 null,
                 BlockFunctionBody()))))));
 
-        var x1Decl = tree.GetNode<ParameterSyntax>(0);
-        var x2Decl = tree.GetNode<ParameterSyntax>(1);
+        var x1Decl = tree.GetNode<NormalParameterSyntax>(0);
+        var x2Decl = tree.GetNode<NormalParameterSyntax>(1);
 
         // Act
         var compilation = CreateCompilation(tree);
@@ -190,7 +190,7 @@ public void LocalFunctionContributesToOverloading()
         var tree = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 name: "foo",
-                parameters: ParameterList(Parameter("x", NameType("int32"))),
+                parameters: ParameterList(NormalParameter("x", NameType("int32"))),
                 returnType: null,
                 body: BlockFunctionBody()),
             FunctionDeclaration(
@@ -200,7 +200,7 @@ public void LocalFunctionContributesToOverloading()
                 body: BlockFunctionBody(
                     DeclarationStatement(FunctionDeclaration(
                         name: "foo",
-                        parameters: ParameterList(Parameter("x", NameType("string"))),
+                        parameters: ParameterList(NormalParameter("x", NameType("string"))),
                         returnType: null,
                         body: BlockFunctionBody())),
                     ExpressionStatement(CallExpression(NameExpression("foo"), LiteralExpression(0))),
diff --git a/src/Draco.Compiler.Tests/Semantics/OverloadingTests.cs b/src/Draco.Compiler.Tests/Semantics/OverloadingTests.cs
index f8b21befe..7987b5067 100644
--- a/src/Draco.Compiler.Tests/Semantics/OverloadingTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/OverloadingTests.cs
@@ -18,34 +18,34 @@ public sealed class OverloadingTests
     private static IEnumerable<DeclarationSyntax> GetGenericListOverloads() => [
         FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("l", GenericType(NameType("List"), NameType("int32")))),
+            ParameterList(NormalParameter("l", GenericType(NameType("List"), NameType("int32")))),
             null,
             BlockFunctionBody()),
         FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("l", GenericType(NameType("List"), NameType("string")))),
+            ParameterList(NormalParameter("l", GenericType(NameType("List"), NameType("string")))),
             null,
             BlockFunctionBody()),
         FunctionDeclaration(
             "foo",
             GenericParameterList(GenericParameter("T")),
-            ParameterList(Parameter("l", GenericType(NameType("List"), NameType("T")))),
+            ParameterList(NormalParameter("l", GenericType(NameType("List"), NameType("T")))),
             null,
             BlockFunctionBody()),
         FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("l", GenericType(NameType("IEnumerable"), NameType("int32")))),
+            ParameterList(NormalParameter("l", GenericType(NameType("IEnumerable"), NameType("int32")))),
             null,
             BlockFunctionBody()),
         FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("l", GenericType(NameType("IEnumerable"), NameType("string")))),
+            ParameterList(NormalParameter("l", GenericType(NameType("IEnumerable"), NameType("string")))),
             null,
             BlockFunctionBody()),
         FunctionDeclaration(
             "foo",
             GenericParameterList(GenericParameter("T")),
-            ParameterList(Parameter("l", GenericType(NameType("IEnumerable"), NameType("T")))),
+            ParameterList(NormalParameter("l", GenericType(NameType("IEnumerable"), NameType("T")))),
             null,
             BlockFunctionBody()),
     ];
diff --git a/src/Draco.Compiler.Tests/Semantics/ReturnsOnAllPathsTests.cs b/src/Draco.Compiler.Tests/Semantics/ReturnsOnAllPathsTests.cs
index 0c65af6c7..efc977dcd 100644
--- a/src/Draco.Compiler.Tests/Semantics/ReturnsOnAllPathsTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/ReturnsOnAllPathsTests.cs
@@ -98,7 +98,7 @@ public void NonUnitMethodReturnsConditionally()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             NameType("int32"),
             BlockFunctionBody(
                 ExpressionStatement(IfExpression(
@@ -124,7 +124,7 @@ public void NonUnitMethodReturnsConditionallyOnBothBranches()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             NameType("int32"),
             BlockFunctionBody(
                 ExpressionStatement(IfExpression(
@@ -151,7 +151,7 @@ public void NonUnitMethodReturnsConditionallyButThenUnconditionally()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             NameType("int32"),
             BlockFunctionBody(
                 ExpressionStatement(IfExpression(
@@ -177,7 +177,7 @@ public void NonUnitMethodReturnsInConditionalLoop()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             NameType("int32"),
             BlockFunctionBody(
                 ExpressionStatement(WhileExpression(
diff --git a/src/Draco.Compiler.Tests/Semantics/SingleAssignmentTests.cs b/src/Draco.Compiler.Tests/Semantics/SingleAssignmentTests.cs
index d3669c9e9..c4064fea9 100644
--- a/src/Draco.Compiler.Tests/Semantics/SingleAssignmentTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/SingleAssignmentTests.cs
@@ -66,7 +66,7 @@ public void AssignImmutableInMutuallyExclusiveBranches()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             null,
             BlockFunctionBody(
                 DeclarationStatement(ImmutableVariableDeclaration(true, "x", NameType("int32"))),
@@ -95,7 +95,7 @@ public void ConditionallyAndThenUnconditionallyAssignImmutable()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             null,
             BlockFunctionBody(
                 DeclarationStatement(ImmutableVariableDeclaration(true, "x", NameType("int32"))),
@@ -124,7 +124,7 @@ public void AssignImmutableInLoop()
         // }
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("b", NameType("bool"))),
+            ParameterList(NormalParameter("b", NameType("bool"))),
             null,
             BlockFunctionBody(
                 DeclarationStatement(ImmutableVariableDeclaration(true, "x", NameType("int32"))),
diff --git a/src/Draco.Compiler.Tests/Semantics/SymbolResolutionTests.cs b/src/Draco.Compiler.Tests/Semantics/SymbolResolutionTests.cs
index f9479a94b..9711e1959 100644
--- a/src/Draco.Compiler.Tests/Semantics/SymbolResolutionTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/SymbolResolutionTests.cs
@@ -40,7 +40,7 @@ public void BasicScopeTree()
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
             ParameterList(
-                Parameter("n", NameType("int32"))),
+                NormalParameter("n", NameType("int32"))),
             null,
             BlockFunctionBody(
                 DeclarationStatement(VariableDeclaration(true, "x1")),
@@ -53,7 +53,7 @@ public void BasicScopeTree()
                     ExpressionStatement(BlockExpression(DeclarationStatement(VariableDeclaration(true, "x6"))))))))));
 
         var foo = tree.GetNode<FunctionDeclarationSyntax>();
-        var n = tree.GetNode<ParameterSyntax>();
+        var n = tree.GetNode<NormalParameterSyntax>();
         var x1 = tree.GetNode<VariableDeclarationSyntax>(0);
         var x2 = tree.GetNode<VariableDeclarationSyntax>(1);
         var x3 = tree.GetNode<VariableDeclarationSyntax>(2);
@@ -327,13 +327,13 @@ public void ParameterRedefinitionError()
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
             ParameterList(
-                Parameter("x", NameType("int32")),
-                Parameter("x", NameType("int32"))),
+                NormalParameter("x", NameType("int32")),
+                NormalParameter("x", NameType("int32"))),
             null,
             BlockFunctionBody())));
 
-        var x1Decl = tree.GetNode<ParameterSyntax>(0);
-        var x2Decl = tree.GetNode<ParameterSyntax>(1);
+        var x1Decl = tree.GetNode<NormalParameterSyntax>(0);
+        var x2Decl = tree.GetNode<NormalParameterSyntax>(1);
 
         // Act
         var compilation = CreateCompilation(tree);
@@ -361,14 +361,14 @@ public void RedefinedParameterReference()
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
             ParameterList(
-                Parameter("x", NameType("int32")),
-                Parameter("x", NameType("int32"))),
+                NormalParameter("x", NameType("int32")),
+                NormalParameter("x", NameType("int32"))),
             null,
             BlockFunctionBody(
                 DeclarationStatement(VariableDeclaration(true, "y", null, NameExpression("x")))))));
 
-        var x1Decl = tree.GetNode<ParameterSyntax>(0);
-        var x2Decl = tree.GetNode<ParameterSyntax>(1);
+        var x1Decl = tree.GetNode<NormalParameterSyntax>(0);
+        var x2Decl = tree.GetNode<NormalParameterSyntax>(1);
         var xRef = tree.GetNode<NameExpressionSyntax>(0);
 
         // Act
@@ -418,7 +418,7 @@ public void FuncOverloadsGlobalVar()
             VariableDeclaration(true, "b", NameType("int32")),
             FunctionDeclaration(
                 "b",
-                ParameterList(Parameter("b", NameType("int32"))),
+                ParameterList(NormalParameter("b", NameType("int32"))),
                 NameType("int32"),
                 InlineFunctionBody(NameExpression("b")))));
 
@@ -1664,7 +1664,7 @@ public void UndefinedTypeInParameterType()
         // Arrange
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("x", NameType("unknown"))),
+            ParameterList(NormalParameter("x", NameType("unknown"))),
             null,
             BlockFunctionBody())));
 
@@ -3246,7 +3246,7 @@ public void GenericFunction()
         var tree = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
             GenericParameterList(GenericParameter("T")),
-            ParameterList(Parameter("x", NameType("T"))),
+            ParameterList(NormalParameter("x", NameType("T"))),
             NameType("T"),
             InlineFunctionBody(NameExpression("x")))));
 
diff --git a/src/Draco.Compiler.Tests/Semantics/TypeCheckingTests.cs b/src/Draco.Compiler.Tests/Semantics/TypeCheckingTests.cs
index 6583a3585..761246072 100644
--- a/src/Draco.Compiler.Tests/Semantics/TypeCheckingTests.cs
+++ b/src/Draco.Compiler.Tests/Semantics/TypeCheckingTests.cs
@@ -655,7 +655,7 @@ public void OneVisibleAndOneNotVisibleOverloadImported()
             FunctionDeclaration(
                 Api.Semantics.Visibility.Internal,
                 "foo",
-                ParameterList(Parameter("x", NameType("string"))),
+                ParameterList(NormalParameter("x", NameType("string"))),
                 NameType("int32"),
                 InlineFunctionBody(LiteralExpression(0)))),
            ToPath("Tests", "FooModule", "foo.draco"));
@@ -702,7 +702,7 @@ public void OneVisibleAndOneNotVisibleOverloadFullyQualified()
             FunctionDeclaration(
                 Api.Semantics.Visibility.Internal,
                 "foo",
-                ParameterList(Parameter("x", NameType("string"))),
+                ParameterList(NormalParameter("x", NameType("string"))),
                 NameType("int32"),
                 InlineFunctionBody(LiteralExpression(0)))),
            ToPath("Tests", "FooModule", "foo.draco"));
@@ -736,12 +736,12 @@ public void OkOverloading()
         var tree = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "foo",
-                ParameterList(Parameter("x", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("int32"))),
                 null,
                 BlockFunctionBody()),
             FunctionDeclaration(
                 "foo",
-                ParameterList(Parameter("x", NameType("bool"))),
+                ParameterList(NormalParameter("x", NameType("bool"))),
                 null,
                 BlockFunctionBody()),
             FunctionDeclaration(
@@ -788,12 +788,12 @@ public void OkNestedOverloading()
         var tree = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "foo",
-                ParameterList(Parameter("x", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("int32"))),
                 null,
                 BlockFunctionBody(
                     DeclarationStatement(FunctionDeclaration(
                         "foo",
-                        ParameterList(Parameter("x", NameType("bool"))),
+                        ParameterList(NormalParameter("x", NameType("bool"))),
                         null,
                         BlockFunctionBody())),
                     ExpressionStatement(CallExpression(NameExpression("foo"), LiteralExpression(0))),
@@ -837,12 +837,12 @@ public void NestedOverloadNotVisibleFromOutside()
         var tree = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "foo",
-                ParameterList(Parameter("x", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("int32"))),
                 null,
                 BlockFunctionBody(
                     DeclarationStatement(FunctionDeclaration(
                         "foo",
-                        ParameterList(Parameter("x", NameType("bool"))),
+                        ParameterList(NormalParameter("x", NameType("bool"))),
                         null,
                         BlockFunctionBody())))),
             FunctionDeclaration(
@@ -888,12 +888,12 @@ public void IllegalOverloading()
         var tree = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "foo",
-                ParameterList(Parameter("x", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("int32"))),
                 null,
                 BlockFunctionBody()),
             FunctionDeclaration(
                 "foo",
-                ParameterList(Parameter("x", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("int32"))),
                 null,
                 BlockFunctionBody())));
 
@@ -919,13 +919,13 @@ public void IllegalOverloadingWithGenerics()
             FunctionDeclaration(
                 "foo",
                 GenericParameterList(GenericParameter("T")),
-                ParameterList(Parameter("x", NameType("int32")), Parameter("y", NameType("T"))),
+                ParameterList(NormalParameter("x", NameType("int32")), NormalParameter("y", NameType("T"))),
                 null,
                 BlockFunctionBody()),
             FunctionDeclaration(
                 "foo",
                 GenericParameterList(GenericParameter("T")),
-                ParameterList(Parameter("x", NameType("int32")), Parameter("y", NameType("T"))),
+                ParameterList(NormalParameter("x", NameType("int32")), NormalParameter("y", NameType("T"))),
                 null,
                 BlockFunctionBody())));
 
@@ -951,12 +951,12 @@ public void IllegalNestedOverloading()
         var tree = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "foo",
-                ParameterList(Parameter("x", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("int32"))),
                 null,
                 BlockFunctionBody(
                     DeclarationStatement(FunctionDeclaration(
                         "foo",
-                        ParameterList(Parameter("x", NameType("int32"))),
+                        ParameterList(NormalParameter("x", NameType("int32"))),
                         null,
                         BlockFunctionBody()))))));
 
@@ -992,12 +992,12 @@ public void NestedMatchingLocalOverloads()
         var tree = SyntaxTree.Create(CompilationUnit(
             FunctionDeclaration(
                 "foo",
-                ParameterList(Parameter("x", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("int32"))),
                 null,
                 BlockFunctionBody(
                     DeclarationStatement(FunctionDeclaration(
                         "foo",
-                        ParameterList(Parameter("x", NameType("bool"))),
+                        ParameterList(NormalParameter("x", NameType("bool"))),
                         null,
                         BlockFunctionBody(
                             ExpressionStatement(CallExpression(NameExpression("foo"), LiteralExpression(0))),
@@ -1009,7 +1009,7 @@ public void NestedMatchingLocalOverloads()
                 BlockFunctionBody(
                     DeclarationStatement(FunctionDeclaration(
                         "foo",
-                        ParameterList(Parameter("x", NameType("bool"))),
+                        ParameterList(NormalParameter("x", NameType("bool"))),
                         null,
                         BlockFunctionBody(
                             ExpressionStatement(CallExpression(NameExpression("foo"), LiteralExpression(0))),
@@ -1191,7 +1191,7 @@ public void ExplicitGenericFunction()
             FunctionDeclaration(
                 "identity",
                 GenericParameterList(GenericParameter("T")),
-                ParameterList(Parameter("x", NameType("T"))),
+                ParameterList(NormalParameter("x", NameType("T"))),
                 NameType("T"),
                 InlineFunctionBody(NameExpression("x"))),
             FunctionDeclaration(
@@ -1269,7 +1269,7 @@ public void ExplicitGenericFunctionWithWrongNumberOfArgs()
             FunctionDeclaration(
                 "identity",
                 GenericParameterList(GenericParameter("T")),
-                ParameterList(Parameter("x", NameType("T"))),
+                ParameterList(NormalParameter("x", NameType("T"))),
                 NameType("T"),
                 InlineFunctionBody(NameExpression("x"))),
             FunctionDeclaration(
@@ -1362,7 +1362,7 @@ public void InferGenericFunctionParameterTypeFromUse()
             FunctionDeclaration(
                 "identity",
                 GenericParameterList(GenericParameter("T")),
-                ParameterList(Parameter("x", NameType("T"))),
+                ParameterList(NormalParameter("x", NameType("T"))),
                 NameType("T"),
                 InlineFunctionBody(NameExpression("x"))),
             FunctionDeclaration(
@@ -1490,12 +1490,12 @@ public void ExactMatchOverloadPriorityOverGeneric()
             FunctionDeclaration(
                 "identity",
                 GenericParameterList(GenericParameter("T")),
-                ParameterList(Parameter("x", NameType("T"))),
+                ParameterList(NormalParameter("x", NameType("T"))),
                 NameType("T"),
                 InlineFunctionBody(NameExpression("x"))),
             FunctionDeclaration(
                 "identity",
-                ParameterList(Parameter("x", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("int32"))),
                 NameType("int32"),
                 InlineFunctionBody(NameExpression("x"))),
             FunctionDeclaration(
@@ -1551,13 +1551,13 @@ public void AmbiguousOverload()
             FunctionDeclaration(
                 "foo",
                 GenericParameterList(GenericParameter("T")),
-                ParameterList(Parameter("x", NameType("T")), Parameter("y", NameType("int32"))),
+                ParameterList(NormalParameter("x", NameType("T")), NormalParameter("y", NameType("int32"))),
                 null,
                 BlockFunctionBody()),
             FunctionDeclaration(
                 "foo",
                 GenericParameterList(GenericParameter("T")),
-                ParameterList(Parameter("x", NameType("int32")), Parameter("y", NameType("T"))),
+                ParameterList(NormalParameter("x", NameType("int32")), NormalParameter("y", NameType("T"))),
                 null,
                 BlockFunctionBody()),
             FunctionDeclaration(
@@ -1595,14 +1595,14 @@ public void VariadicOverloadPriority()
             FunctionDeclaration(
                 "bar",
                 ParameterList(
-                    Parameter("s", NameType("string")),
-                    Parameter("x", NameType("int32"))),
+                    NormalParameter("s", NameType("string")),
+                    NormalParameter("x", NameType("int32"))),
                 NameType("int32"),
                 InlineFunctionBody(LiteralExpression(0))),
             FunctionDeclaration(
                 "bar",
                 ParameterList(
-                    Parameter("s", NameType("string")),
+                    NormalParameter("s", NameType("string")),
                     VariadicParameter("x", GenericType(NameType("Array"), NameType("int32")))),
                 NameType("int32"),
                 InlineFunctionBody(LiteralExpression(0))),
@@ -1666,15 +1666,15 @@ public void GenericVariadicOverloadPriority()
                 "bar",
                 GenericParameterList(GenericParameter("T")),
                 ParameterList(
-                    Parameter("s", NameType("string")),
-                    Parameter("x", NameType("T"))),
+                    NormalParameter("s", NameType("string")),
+                    NormalParameter("x", NameType("T"))),
                 NameType("int32"),
                 InlineFunctionBody(LiteralExpression(0))),
             FunctionDeclaration(
                 "bar",
                 GenericParameterList(GenericParameter("T")),
                 ParameterList(
-                    Parameter("s", NameType("string")),
+                    NormalParameter("s", NameType("string")),
                     VariadicParameter("x", GenericType(NameType("Array"), NameType("T")))),
                 NameType("int32"),
                 InlineFunctionBody(LiteralExpression(0))),
@@ -1732,8 +1732,8 @@ public void InferredGenericsMismatch()
                 "foo",
                 GenericParameterList(GenericParameter("T")),
                 ParameterList(
-                    Parameter("x", NameType("T")),
-                    Parameter("y", NameType("T"))),
+                    NormalParameter("x", NameType("T")),
+                    NormalParameter("y", NameType("T"))),
                 null,
                 BlockFunctionBody()),
             FunctionDeclaration(
@@ -1886,7 +1886,7 @@ public void PassDerivedTypeToBaseTypeParameter()
                     ExpressionStatement(CallExpression(NameExpression("bar"), CallExpression(NameExpression("Random")))))),
             FunctionDeclaration(
                 "bar",
-                ParameterList(Parameter("x", NameType("Object"))),
+                ParameterList(NormalParameter("x", NameType("Object"))),
                 null,
                 BlockFunctionBody())));
 
@@ -1922,7 +1922,7 @@ public void PassBaseTypeToDerivedTypeParameter()
                     ExpressionStatement(CallExpression(NameExpression("bar"), CallExpression(NameExpression("Object")))))),
             FunctionDeclaration(
                 "bar",
-                ParameterList(Parameter("x", NameType("String"))),
+                ParameterList(NormalParameter("x", NameType("String"))),
                 null,
                 BlockFunctionBody())));
 
@@ -1961,12 +1961,12 @@ public void BaseTypeArgumentOverloading()
                     ExpressionStatement(CallExpression(NameExpression("bar"), CallExpression(NameExpression("Object")))))),
             FunctionDeclaration(
                 "bar",
-                ParameterList(Parameter("x", NameType("Object"))),
+                ParameterList(NormalParameter("x", NameType("Object"))),
                 null,
                 BlockFunctionBody()),
             FunctionDeclaration(
                 "bar",
-                ParameterList(Parameter("x", NameType("Random"))),
+                ParameterList(NormalParameter("x", NameType("Random"))),
                 null,
                 BlockFunctionBody())));
 
@@ -2019,9 +2019,9 @@ public void BaseTypeGenericsCall()
                 "bar",
                 GenericParameterList(GenericParameter("T")),
                 ParameterList(
-                    Parameter("x", NameType("T")),
-                    Parameter("y", NameType("T")),
-                    Parameter("z", NameType("T"))),
+                    NormalParameter("x", NameType("T")),
+                    NormalParameter("y", NameType("T")),
+                    NormalParameter("z", NameType("T"))),
                 null,
                 BlockFunctionBody())));
 
@@ -2417,7 +2417,7 @@ public void GenericTypeNotInstantiatedInTypeContextIsAnError()
 
         var main = SyntaxTree.Create(CompilationUnit(FunctionDeclaration(
             "foo",
-            ParameterList(Parameter("a", NameType("Array2D"))),
+            ParameterList(NormalParameter("a", NameType("Array2D"))),
             null,
             BlockFunctionBody())));
 
diff --git a/src/Draco.Compiler.Tests/Syntax/ParserTests.cs b/src/Draco.Compiler.Tests/Syntax/ParserTests.cs
index 08f6e8ea5..f44cac6fc 100644
--- a/src/Draco.Compiler.Tests/Syntax/ParserTests.cs
+++ b/src/Draco.Compiler.Tests/Syntax/ParserTests.cs
@@ -100,7 +100,7 @@ func main() {
                 this.T(TokenKind.Identifier);
 
                 this.T(TokenKind.ParenOpen);
-                this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+                this.N<SeparatedSyntaxList<ParameterSyntax>>();
                 this.T(TokenKind.ParenClose);
 
                 this.N<BlockFunctionBodySyntax>();
@@ -170,7 +170,7 @@ func main() {
                 this.T(TokenKind.Identifier);
 
                 this.T(TokenKind.ParenOpen);
-                this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+                this.N<SeparatedSyntaxList<ParameterSyntax>>();
                 this.T(TokenKind.ParenClose);
 
                 this.N<BlockFunctionBodySyntax>();
@@ -199,7 +199,7 @@ func main() {
                 this.T(TokenKind.Identifier);
 
                 this.T(TokenKind.ParenOpen);
-                this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+                this.N<SeparatedSyntaxList<ParameterSyntax>>();
                 this.T(TokenKind.ParenClose);
 
                 this.N<BlockFunctionBodySyntax>();
@@ -247,7 +247,7 @@ func foo<T, U>() {
                 }
 
                 this.T(TokenKind.ParenOpen);
-                this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+                this.N<SeparatedSyntaxList<ParameterSyntax>>();
                 this.T(TokenKind.ParenClose);
 
                 this.N<BlockFunctionBodySyntax>();
@@ -1988,9 +1988,9 @@ func foo(@Attr2("this is a parameter") x: int32) {}
             this.T(TokenKind.KeywordFunc);
             this.T(TokenKind.Identifier, "foo");
             this.T(TokenKind.ParenOpen);
-            this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+            this.N<SeparatedSyntaxList<ParameterSyntax>>();
             {
-                this.N<ParameterSyntax>();
+                this.N<NormalParameterSyntax>();
                 {
                     this.N<SyntaxList<AttributeSyntax>>();
                     this.N<AttributeSyntax>();
@@ -2051,7 +2051,7 @@ public func bar() {}
             this.T(TokenKind.KeywordFunc);
             this.T(TokenKind.Identifier, "foo");
             this.T(TokenKind.ParenOpen);
-            this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+            this.N<SeparatedSyntaxList<ParameterSyntax>>();
             this.T(TokenKind.ParenClose);
             this.N<BlockFunctionBodySyntax>();
             {
@@ -2064,7 +2064,7 @@ public func bar() {}
                     this.T(TokenKind.KeywordFunc);
                     this.T(TokenKind.Identifier, "bar");
                     this.T(TokenKind.ParenOpen);
-                    this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+                    this.N<SeparatedSyntaxList<ParameterSyntax>>();
                     this.T(TokenKind.ParenClose);
                     this.N<BlockFunctionBodySyntax>();
                     {
@@ -2096,7 +2096,7 @@ public void TestEmptyGenericParameterList()
                 this.T(TokenKind.GreaterThan);
             }
             this.T(TokenKind.ParenOpen);
-            this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+            this.N<SeparatedSyntaxList<ParameterSyntax>>();
             this.T(TokenKind.ParenClose);
             this.N<BlockFunctionBodySyntax>();
             {
@@ -2119,9 +2119,9 @@ func foo(x: List<>) {}
             this.T(TokenKind.KeywordFunc);
             this.T(TokenKind.Identifier, "foo");
             this.T(TokenKind.ParenOpen);
-            this.N<SeparatedSyntaxList<ParameterSyntaxBase>>();
+            this.N<SeparatedSyntaxList<ParameterSyntax>>();
             {
-                this.N<ParameterSyntax>();
+                this.N<NormalParameterSyntax>();
                 {
                     this.T(TokenKind.Identifier, "x");
                     this.T(TokenKind.Colon);
diff --git a/src/Draco.Compiler/Api/Services/CodeCompletion/CompletionService.cs b/src/Draco.Compiler/Api/Services/CodeCompletion/CompletionService.cs
index 318d3c1f2..38b9c3ed1 100644
--- a/src/Draco.Compiler/Api/Services/CodeCompletion/CompletionService.cs
+++ b/src/Draco.Compiler/Api/Services/CodeCompletion/CompletionService.cs
@@ -87,7 +87,7 @@ public ImmutableArray<CompletionItem> GetCompletions(SemanticModel semanticModel
             // Type expression
             NameTypeSyntax => CompletionContext.Type,
             // Parameter name declaration
-            ParameterSyntax => CompletionContext.None,
+            NormalParameterSyntax => CompletionContext.None,
             // Global declaration
             UnexpectedDeclarationSyntax => CompletionContext.Declaration,
             // Declaring identifier
diff --git a/src/Draco.Compiler/Api/Syntax/SyntaxFactory.cs b/src/Draco.Compiler/Api/Syntax/SyntaxFactory.cs
index a0a11b340..321b3935c 100644
--- a/src/Draco.Compiler/Api/Syntax/SyntaxFactory.cs
+++ b/src/Draco.Compiler/Api/Syntax/SyntaxFactory.cs
@@ -93,16 +93,16 @@ public static SeparatedSyntaxList<TNode> SeparatedSyntaxList<TNode>(SyntaxToken
     public static SeparatedSyntaxList<TNode> SeparatedSyntaxList<TNode>(SyntaxToken separator, params TNode[] elements)
         where TNode : SyntaxNode => SeparatedSyntaxList(separator, elements.AsEnumerable());
 
-    public static SeparatedSyntaxList<ParameterSyntaxBase> ParameterList(IEnumerable<ParameterSyntaxBase> parameters) =>
+    public static SeparatedSyntaxList<ParameterSyntax> ParameterList(IEnumerable<ParameterSyntax> parameters) =>
         SeparatedSyntaxList(Comma, parameters);
-    public static SeparatedSyntaxList<ParameterSyntaxBase> ParameterList(params ParameterSyntaxBase[] parameters) =>
+    public static SeparatedSyntaxList<ParameterSyntax> ParameterList(params ParameterSyntax[] parameters) =>
         SeparatedSyntaxList(Comma, parameters);
-    public static ParameterSyntax Parameter(string name, TypeSyntax type) =>
-        Parameter([], name, type);
-    public static ParameterSyntax Parameter(IEnumerable<AttributeSyntax> attributes, string name, TypeSyntax type) =>
-        Parameter(SyntaxList(attributes), null, Identifier(name), Colon, type);
-    public static ParameterSyntax VariadicParameter(string name, TypeSyntax type) =>
-        Parameter(SyntaxList<AttributeSyntax>(), Ellipsis, Identifier(name), Colon, type);
+    public static NormalParameterSyntax NormalParameter(string name, TypeSyntax type) =>
+        NormalParameter([], name, type);
+    public static NormalParameterSyntax NormalParameter(IEnumerable<AttributeSyntax> attributes, string name, TypeSyntax type) =>
+        NormalParameter(SyntaxList(attributes), null, Identifier(name), Colon, type);
+    public static NormalParameterSyntax VariadicParameter(string name, TypeSyntax type) =>
+        NormalParameter(SyntaxList<AttributeSyntax>(), Ellipsis, Identifier(name), Colon, type);
 
     public static GenericParameterListSyntax GenericParameterList(IEnumerable<GenericParameterSyntax> parameters) =>
         GenericParameterList(SeparatedSyntaxList(Comma, parameters));
@@ -123,7 +123,7 @@ public static ImportDeclarationSyntax ImportDeclaration(string root, params stri
 
     public static FunctionDeclarationSyntax FunctionDeclaration(
         string name,
-        SeparatedSyntaxList<ParameterSyntaxBase> parameters,
+        SeparatedSyntaxList<ParameterSyntax> parameters,
         TypeSyntax? returnType,
         FunctionBodySyntax body) =>
         FunctionDeclaration([], Semantics.Visibility.Private, name, null, parameters, returnType, body);
@@ -131,7 +131,7 @@ public static FunctionDeclarationSyntax FunctionDeclaration(
     public static FunctionDeclarationSyntax FunctionDeclaration(
         IEnumerable<AttributeSyntax> attributes,
         string name,
-        SeparatedSyntaxList<ParameterSyntaxBase> parameters,
+        SeparatedSyntaxList<ParameterSyntax> parameters,
         TypeSyntax? returnType,
         FunctionBodySyntax body) =>
         FunctionDeclaration(attributes, Semantics.Visibility.Private, name, null, parameters, returnType, body);
@@ -139,7 +139,7 @@ public static FunctionDeclarationSyntax FunctionDeclaration(
     public static FunctionDeclarationSyntax FunctionDeclaration(
         Visibility visibility,
         string name,
-        SeparatedSyntaxList<ParameterSyntaxBase> parameters,
+        SeparatedSyntaxList<ParameterSyntax> parameters,
         TypeSyntax? returnType,
         FunctionBodySyntax body) =>
         FunctionDeclaration([], visibility, name, null, parameters, returnType, body);
@@ -147,7 +147,7 @@ public static FunctionDeclarationSyntax FunctionDeclaration(
     public static FunctionDeclarationSyntax FunctionDeclaration(
         string name,
         GenericParameterListSyntax? generics,
-        SeparatedSyntaxList<ParameterSyntaxBase> parameters,
+        SeparatedSyntaxList<ParameterSyntax> parameters,
         TypeSyntax? returnType,
         FunctionBodySyntax body) =>
         FunctionDeclaration([], Semantics.Visibility.Private, name, generics, parameters, returnType, body);
@@ -157,7 +157,7 @@ public static FunctionDeclarationSyntax FunctionDeclaration(
         Visibility visibility,
         string name,
         GenericParameterListSyntax? generics,
-        SeparatedSyntaxList<ParameterSyntaxBase> parameters,
+        SeparatedSyntaxList<ParameterSyntax> parameters,
         TypeSyntax? returnType,
         FunctionBodySyntax body) => FunctionDeclaration(
         attributes,
diff --git a/src/Draco.Compiler/Api/Syntax/SyntaxFacts.cs b/src/Draco.Compiler/Api/Syntax/SyntaxFacts.cs
index 078baffe7..3661d6972 100644
--- a/src/Draco.Compiler/Api/Syntax/SyntaxFacts.cs
+++ b/src/Draco.Compiler/Api/Syntax/SyntaxFacts.cs
@@ -157,7 +157,7 @@ _ when IsMissing(node) => false,
             ModuleDeclarationSyntax md => !IsMissing(md.CloseBrace),
             ImportDeclarationSyntax id => !IsMissing(id.Semicolon),
             FunctionDeclarationSyntax fd => IsCompleteEntry(fd.Body),
-            ParameterSyntax p => IsCompleteEntry(p.Type),
+            NormalParameterSyntax p => IsCompleteEntry(p.Type),
             BlockFunctionBodySyntax bfb => !IsMissing(bfb.CloseBrace),
             InlineFunctionBodySyntax ifb => !IsMissing(ifb.Semicolon),
             LabelDeclarationSyntax ld => !IsMissing(ld.Colon),
diff --git a/src/Draco.Compiler/Api/Syntax/SyntaxHighlighter.cs b/src/Draco.Compiler/Api/Syntax/SyntaxHighlighter.cs
index 6e50d7956..2e49eea72 100644
--- a/src/Draco.Compiler/Api/Syntax/SyntaxHighlighter.cs
+++ b/src/Draco.Compiler/Api/Syntax/SyntaxHighlighter.cs
@@ -140,7 +140,7 @@ or TokenKind.BracketOpen
     private static IEnumerable<HighlightFragment> Identifier(SyntaxToken token, SemanticModel? semanticModel)
     {
         // Make a guess based on syntax
-        if (token.Parent is ParameterSyntax param && param.Name.Equals(token))
+        if (token.Parent is NormalParameterSyntax param && param.Name.Equals(token))
         {
             return Fragment(token, SyntaxColoring.ParameterName);
         }
diff --git a/src/Draco.Compiler/Internal/Binding/BinderFacts.cs b/src/Draco.Compiler/Internal/Binding/BinderFacts.cs
index 0108c1ace..c8f9d9ba9 100644
--- a/src/Draco.Compiler/Internal/Binding/BinderFacts.cs
+++ b/src/Draco.Compiler/Internal/Binding/BinderFacts.cs
@@ -133,7 +133,7 @@ or ForExpressionSyntax
     public static bool DefinesSymbol(SyntaxNode node) => node
         is FunctionDeclarationSyntax
         or VariableDeclarationSyntax
-        or ParameterSyntax
+        or NormalParameterSyntax
         or LabelDeclarationSyntax
         or ClassDeclarationSyntax;
 
diff --git a/src/Draco.Compiler/Internal/Binding/Binder_Expression.cs b/src/Draco.Compiler/Internal/Binding/Binder_Expression.cs
index c8677c549..52e414482 100644
--- a/src/Draco.Compiler/Internal/Binding/Binder_Expression.cs
+++ b/src/Draco.Compiler/Internal/Binding/Binder_Expression.cs
@@ -13,15 +13,7 @@
 using Draco.Compiler.Internal.Symbols;
 using Draco.Compiler.Internal.Symbols.Error;
 using Draco.Compiler.Internal.Symbols.Syntax;
-using FieldSymbol = Draco.Compiler.Internal.Symbols.FieldSymbol;
-using FunctionGroupSymbol = Draco.Compiler.Internal.Symbols.Synthetized.FunctionGroupSymbol;
-using FunctionSymbol = Draco.Compiler.Internal.Symbols.FunctionSymbol;
-using LabelSymbol = Draco.Compiler.Internal.Symbols.LabelSymbol;
-using LocalSymbol = Draco.Compiler.Internal.Symbols.LocalSymbol;
-using ModuleSymbol = Draco.Compiler.Internal.Symbols.ModuleSymbol;
-using ParameterSymbol = Draco.Compiler.Internal.Symbols.ParameterSymbol;
-using PropertySymbol = Draco.Compiler.Internal.Symbols.PropertySymbol;
-using TypeSymbol = Draco.Compiler.Internal.Symbols.TypeSymbol;
+using Draco.Compiler.Internal.Symbols.Synthetized;
 
 namespace Draco.Compiler.Internal.Binding;
 
@@ -74,7 +66,7 @@ private async BindingTask<BoundExpression> BindExpressionToValueProducingExpress
         UnaryExpressionSyntax ury => this.BindUnaryExpression(ury, constraints, diagnostics),
         BinaryExpressionSyntax bin => this.BindBinaryExpression(bin, constraints, diagnostics),
         RelationalExpressionSyntax rel => this.BindRelationalExpression(rel, constraints, diagnostics),
-        MemberExpressionSyntax maccess => this.BindMemberExpression(maccess, constraints, diagnostics),
+        MemberExpressionSyntax mem => this.BindMemberExpression(mem, constraints, diagnostics),
         GenericExpressionSyntax gen => this.BindGenericExpression(gen, constraints, diagnostics),
         IndexExpressionSyntax index => this.BindIndexExpression(index, constraints, diagnostics),
         ThisExpressionSyntax @this => this.BindThisExpression(@this, constraints, diagnostics),
@@ -718,10 +710,7 @@ private async BindingTask<BoundExpression> BindIndexExpression(IndexExpressionSy
             // Array getter
             return new BoundArrayAccessExpression(syntax, receiver, await BindingTask.WhenAll(argsTask));
         }
-        else
-        {
-            return new BoundIndexGetExpression(syntax, receiver, indexer, await BindingTask.WhenAll(argsTask));
-        }
+        return new BoundIndexGetExpression(syntax, receiver, indexer, await BindingTask.WhenAll(argsTask));
     }
 
     private BindingTask<BoundExpression> BindThisExpression(ThisExpressionSyntax syntax, ConstraintSolver constraints, DiagnosticBag diagnostics)
@@ -871,16 +860,13 @@ private BindingTask<BoundExpression> WrapFunctions(
                 return BindingTask.FromResult<BoundExpression>(
                     new BoundDelegateCreationExpression(syntax, receiver, functions[0], delegateCtor));
             }
-            else
-            {
-                // TODO: We should construct some constraints to resolve which one
-                // For now we report an error to not crash tools
-                diagnostics.Add(Diagnostic.Create(
-                    template: TypeCheckingErrors.IllegalExpression,
-                    location: syntax.Location));
-                return BindingTask.FromResult<BoundExpression>(
-                    new BoundReferenceErrorExpression(syntax, WellKnownTypes.ErrorType));
-            }
+            // TODO: We should construct some constraints to resolve which one
+            // For now we report an error to not crash tools
+            diagnostics.Add(Diagnostic.Create(
+                template: TypeCheckingErrors.IllegalExpression,
+                location: syntax.Location));
+            return BindingTask.FromResult<BoundExpression>(
+                new BoundReferenceErrorExpression(syntax, WellKnownTypes.ErrorType));
         }
     }
 
diff --git a/src/Draco.Compiler/Internal/Binding/LocalBinder.cs b/src/Draco.Compiler/Internal/Binding/LocalBinder.cs
index 57c99d461..ef569501b 100644
--- a/src/Draco.Compiler/Internal/Binding/LocalBinder.cs
+++ b/src/Draco.Compiler/Internal/Binding/LocalBinder.cs
@@ -168,7 +168,7 @@ private void Build()
     private Symbol? BuildSymbol(SyntaxNode syntax, int localCount) => syntax switch
     {
         FunctionDeclarationSyntax function => new SourceFunctionSymbol(this.ContainingSymbol, function),
-        ParameterSyntax parameter => new SourceParameterSymbol((FunctionSymbol)this.ContainingSymbol, parameter),
+        NormalParameterSyntax parameter => new SourceParameterSymbol((FunctionSymbol)this.ContainingSymbol, parameter),
         VariableDeclarationSyntax variable => variable.FieldKeyword is null ?
             new SourceLocalSymbol(this.ContainingSymbol, new TypeVariable(localCount), variable) :
             new SourceFieldSymbol((TypeSymbol)this.ContainingSymbol, variable),
diff --git a/src/Draco.Compiler/Internal/Declarations/ClassDeclaration.cs b/src/Draco.Compiler/Internal/Declarations/ClassDeclaration.cs
index a1e43c269..93f099509 100644
--- a/src/Draco.Compiler/Internal/Declarations/ClassDeclaration.cs
+++ b/src/Draco.Compiler/Internal/Declarations/ClassDeclaration.cs
@@ -21,13 +21,7 @@ internal sealed class ClassDeclaration(ClassDeclarationSyntax syntax) : Declarat
         InterlockedUtils.InitializeDefault(ref this.children, this.BuildChildren);
     private ImmutableArray<Declaration> children;
 
-    public override IEnumerable<SyntaxNode> DeclaringSyntaxes
-    {
-        get
-        {
-            yield return this.Syntax;
-        }
-    }
+    public override IEnumerable<SyntaxNode> DeclaringSyntaxes => [this.Syntax];
 
     private ImmutableArray<Declaration> BuildChildren()
     {
diff --git a/src/Draco.Compiler/Internal/Declarations/FunctionDeclaration.cs b/src/Draco.Compiler/Internal/Declarations/FunctionDeclaration.cs
index 6ffc27b45..d1904330f 100644
--- a/src/Draco.Compiler/Internal/Declarations/FunctionDeclaration.cs
+++ b/src/Draco.Compiler/Internal/Declarations/FunctionDeclaration.cs
@@ -17,11 +17,5 @@ internal sealed class FunctionDeclaration(FunctionDeclarationSyntax syntax)
 
     public override ImmutableArray<Declaration> Children => [];
 
-    public override IEnumerable<SyntaxNode> DeclaringSyntaxes
-    {
-        get
-        {
-            yield return this.Syntax;
-        }
-    }
+    public override IEnumerable<SyntaxNode> DeclaringSyntaxes => [this.Syntax];
 }
diff --git a/src/Draco.Compiler/Internal/Declarations/GlobalDeclaration.cs b/src/Draco.Compiler/Internal/Declarations/GlobalDeclaration.cs
index 9fcfe7dfb..fef7bfdba 100644
--- a/src/Draco.Compiler/Internal/Declarations/GlobalDeclaration.cs
+++ b/src/Draco.Compiler/Internal/Declarations/GlobalDeclaration.cs
@@ -17,11 +17,5 @@ internal sealed class GlobalDeclaration(VariableDeclarationSyntax syntax)
 
     public override ImmutableArray<Declaration> Children => [];
 
-    public override IEnumerable<SyntaxNode> DeclaringSyntaxes
-    {
-        get
-        {
-            yield return this.Syntax;
-        }
-    }
+    public override IEnumerable<SyntaxNode> DeclaringSyntaxes => [this.Syntax];
 }
diff --git a/src/Draco.Compiler/Internal/Declarations/SingleModuleDeclaration.cs b/src/Draco.Compiler/Internal/Declarations/SingleModuleDeclaration.cs
index b3419e647..c2420a858 100644
--- a/src/Draco.Compiler/Internal/Declarations/SingleModuleDeclaration.cs
+++ b/src/Draco.Compiler/Internal/Declarations/SingleModuleDeclaration.cs
@@ -27,13 +27,7 @@ internal sealed class SingleModuleDeclaration(string name, SplitPath path, Conta
         InterlockedUtils.InitializeDefault(ref this.children, this.BuildChildren);
     private ImmutableArray<Declaration> children;
 
-    public override IEnumerable<SyntaxNode> DeclaringSyntaxes
-    {
-        get
-        {
-            yield return this.Syntax;
-        }
-    }
+    public override IEnumerable<SyntaxNode> DeclaringSyntaxes => [this.Syntax];
 
     private ImmutableArray<Declaration> BuildChildren() =>
         this.Syntax.Declarations.Select(this.BuildChild).OfType<Declaration>().ToImmutableArray();
diff --git a/src/Draco.Compiler/Internal/Symbols/Source/SourceParameterSymbol.cs b/src/Draco.Compiler/Internal/Symbols/Source/SourceParameterSymbol.cs
index ca507aa63..f56897587 100644
--- a/src/Draco.Compiler/Internal/Symbols/Source/SourceParameterSymbol.cs
+++ b/src/Draco.Compiler/Internal/Symbols/Source/SourceParameterSymbol.cs
@@ -12,7 +12,7 @@ namespace Draco.Compiler.Internal.Symbols.Source;
 /// </summary>
 internal sealed class SourceParameterSymbol(
     FunctionSymbol containingSymbol,
-    ParameterSyntax syntax) : ParameterSymbol, ISourceSymbol
+    NormalParameterSyntax syntax) : ParameterSymbol, ISourceSymbol
 {
     public override ImmutableArray<AttributeInstance> Attributes => this.BindAttributesIfNeeded(this.DeclaringCompilation!);
     private ImmutableArray<AttributeInstance> attributes;
@@ -24,7 +24,7 @@ internal sealed class SourceParameterSymbol(
     public override bool IsVariadic => this.DeclaringSyntax.Variadic is not null;
     public override string Name => this.DeclaringSyntax.Name.Text;
 
-    public override ParameterSyntax DeclaringSyntax { get; } = syntax;
+    public override NormalParameterSyntax DeclaringSyntax { get; } = syntax;
 
     public void Bind(IBinderProvider binderProvider)
     {
diff --git a/src/Draco.Compiler/Internal/Symbols/Syntax/SyntaxFunctionSymbol.cs b/src/Draco.Compiler/Internal/Symbols/Syntax/SyntaxFunctionSymbol.cs
index 77f3e9a2a..2ba7d9626 100644
--- a/src/Draco.Compiler/Internal/Symbols/Syntax/SyntaxFunctionSymbol.cs
+++ b/src/Draco.Compiler/Internal/Symbols/Syntax/SyntaxFunctionSymbol.cs
@@ -130,7 +130,7 @@ private ImmutableArray<ParameterSymbol> BindParameters(IBinderProvider binderPro
                 parameters.Add(asSymbol);
                 continue;
             }
-            var parameterSyntax = (ParameterSyntax)syntax;
+            var parameterSyntax = (NormalParameterSyntax)syntax;
 
             var parameterName = parameterSyntax.Name.Text;
 
diff --git a/src/Draco.Compiler/Internal/Syntax/Parser.cs b/src/Draco.Compiler/Internal/Syntax/Parser.cs
index 542f1c5ec..e58a88900 100644
--- a/src/Draco.Compiler/Internal/Syntax/Parser.cs
+++ b/src/Draco.Compiler/Internal/Syntax/Parser.cs
@@ -808,8 +808,8 @@ private DeclarationSyntax ParseLabelDeclaration(
     /// <summary>
     /// Parses a function parameter.
     /// </summary>
-    /// <returns>The parsed <see cref="ParameterSyntax"/>.</returns>
-    private ParameterSyntaxBase ParseParameter()
+    /// <returns>The parsed <see cref="NormalParameterSyntax"/>.</returns>
+    private ParameterSyntax ParseParameter()
     {
         var attributes = this.ParseAttributeList();
         if (this.Matches(TokenKind.KeywordThis, out var thisKeyWord))
@@ -825,7 +825,7 @@ private ParameterSyntaxBase ParseParameter()
         var name = this.Expect(TokenKind.Identifier);
         var colon = this.Expect(TokenKind.Colon);
         var type = this.ParseType();
-        return new ParameterSyntax(attributes, variadic, name, colon, type);
+        return new NormalParameterSyntax(attributes, variadic, name, colon, type);
     }
 
     /// <summary>
diff --git a/src/Draco.Compiler/Internal/Syntax/Syntax.xml b/src/Draco.Compiler/Internal/Syntax/Syntax.xml
index df71aa130..bf5a7dade 100644
--- a/src/Draco.Compiler/Internal/Syntax/Syntax.xml
+++ b/src/Draco.Compiler/Internal/Syntax/Syntax.xml
@@ -481,7 +481,7 @@
 
       <Token Kind="ParenOpen" />
     </Field>
-    <Field Name="ParameterList" Type="SeparatedSyntaxList&lt;ParameterSyntaxBase&gt;">
+    <Field Name="ParameterList" Type="SeparatedSyntaxList&lt;ParameterSyntax&gt;">
       <Documentation>
         The parameters this function declares.
       </Documentation>
@@ -505,13 +505,13 @@
     </Field>
   </Node>
 
-  <AbstractNode Name="ParameterSyntaxBase" Base="SyntaxNode">
+  <AbstractNode Name="ParameterSyntax" Base="SyntaxNode">
     <Documentation>
       A single parameter in a function parameter list.
     </Documentation>
   </AbstractNode>
 
-  <Node Name="ThisParameterSyntax" Base="ParameterSyntaxBase">
+  <Node Name="ThisParameterSyntax" Base="ParameterSyntax">
     <Documentation>
       The this parameter at the first place in a parameter list.
     </Documentation>
@@ -524,7 +524,7 @@
     </Field>
   </Node>
 
-  <Node Name="ParameterSyntax" Base="ParameterSyntaxBase">
+  <Node Name="NormalParameterSyntax" Base="ParameterSyntax">
     <Documentation>
       A single parameter in a function parameter list.
     </Documentation>
diff --git a/src/Draco.LanguageServer/Capabilities/Rename.cs b/src/Draco.LanguageServer/Capabilities/Rename.cs
index 33d492796..c756325cf 100644
--- a/src/Draco.LanguageServer/Capabilities/Rename.cs
+++ b/src/Draco.LanguageServer/Capabilities/Rename.cs
@@ -85,7 +85,7 @@ private static IEnumerable<SyntaxNode> FindAllAppearances(
 
     private static Lsp.Model.TextEdit RenameNode(SyntaxNode original, string name) => original switch
     {
-        ParameterSyntax p => RenameToken(p.Name, name),
+        NormalParameterSyntax p => RenameToken(p.Name, name),
         GenericParameterSyntax g => RenameToken(g.Name, name),
         FunctionDeclarationSyntax f => RenameToken(f.Name, name),
         VariableDeclarationSyntax v => RenameToken(v.Name, name),