Fix type parameter scoping for local functions

dotnet · Mar 11, 2022 · eb2a3c3 · eb2a3c3
1 parent a42e218
commit eb2a3c3
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Showing 3 changed files with 539 additions and 7 deletions.
diff --git a/src/Compilers/CSharp/Portable/Compilation/MemberSemanticModel.cs b/src/Compilers/CSharp/Portable/Compilation/MemberSemanticModel.cs
@@ -358,7 +358,7 @@ private static Binder GetEnclosingBinderInternalWithinRoot(SyntaxNode node, int
                 LocalFunctionSymbol function = GetDeclaredLocalFunction(binder, ownerOfTypeParametersInScope.Identifier);
                 if ((object)function != null)
                 {
-                    binder = function.SignatureBinder;
+                    binder = function.ParameterBinder;
                 }
             }
 

diff --git a/src/Compilers/CSharp/Portable/Symbols/Source/LocalFunctionSymbol.cs b/src/Compilers/CSharp/Portable/Symbols/Source/LocalFunctionSymbol.cs
@@ -15,6 +15,7 @@ namespace Microsoft.CodeAnalysis.CSharp.Symbols
     internal sealed class LocalFunctionSymbol : SourceMethodSymbolWithAttributes
     {
         private readonly Binder _binder;
+        private readonly Binder? _withTypeParamsBinder; // null when no type parameters
         private readonly Symbol _containingSymbol;
         private readonly DeclarationModifiers _declarationModifiers;
         private readonly ImmutableArray<SourceMethodTypeParameterSymbol> _typeParameters;
@@ -60,7 +61,7 @@ internal sealed class LocalFunctionSymbol : SourceMethodSymbolWithAttributes
 
             if (syntax.TypeParameterList != null)
             {
-                binder = new WithMethodTypeParametersBinder(this, binder);
+                _withTypeParamsBinder = new WithMethodTypeParametersBinder(this, binder);
                 _typeParameters = MakeTypeParameters(_declarationDiagnostics);
             }
             else
@@ -105,7 +106,7 @@ internal sealed class LocalFunctionSymbol : SourceMethodSymbolWithAttributes
         /// </summary>
         internal Binder ScopeBinder { get; }
 
-        internal override Binder ParameterBinder => _binder;
+        internal override Binder ParameterBinder => _withTypeParamsBinder ?? _binder;
 
         internal LocalFunctionStatementSyntax Syntax => (LocalFunctionStatementSyntax)syntaxReferenceOpt.GetSyntax();
 
@@ -180,7 +181,7 @@ private void ComputeParameters()
             var diagnostics = BindingDiagnosticBag.GetInstance(_declarationDiagnostics);
 
             var parameters = ParameterHelpers.MakeParameters(
-                _binder,
+                ParameterBinder,
                 this,
                 this.Syntax.ParameterList,
                 arglistToken: out arglistToken,
@@ -239,7 +240,7 @@ internal void ComputeReturnType()
 
             var diagnostics = BindingDiagnosticBag.GetInstance(_declarationDiagnostics);
             TypeSyntax returnTypeSyntax = Syntax.ReturnType;
-            TypeWithAnnotations returnType = _binder.BindType(returnTypeSyntax.SkipRef(), diagnostics);
+            TypeWithAnnotations returnType = ParameterBinder.BindType(returnTypeSyntax.SkipRef(), diagnostics);
 
             var compilation = DeclaringCompilation;
 
@@ -476,7 +477,7 @@ public override ImmutableArray<ImmutableArray<TypeWithAnnotations>> GetTypeParam
                 var syntax = Syntax;
                 var diagnostics = BindingDiagnosticBag.GetInstance(_declarationDiagnostics);
                 var constraints = this.MakeTypeParameterConstraintTypes(
-                    _binder,
+                    ParameterBinder,
                     TypeParameters,
                     syntax.TypeParameterList,
                     syntax.ConstraintClauses,
@@ -501,7 +502,7 @@ public override ImmutableArray<TypeParameterConstraintKind> GetTypeParameterCons
             {
                 var syntax = Syntax;
                 var constraints = this.MakeTypeParameterConstraintKinds(
-                    _binder,
+                    ParameterBinder,
                     TypeParameters,
                     syntax.TypeParameterList,
                     syntax.ConstraintClauses);