Factoring code more

jcouv · Nov 12, 2018 · e81acf5 · e81acf5
1 parent cc016e4
commit e81acf5
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Showing 2 changed files with 16 additions and 27 deletions.
diff --git a/src/Compilers/CSharp/Portable/Binder/InMethodBinder.cs b/src/Compilers/CSharp/Portable/Binder/InMethodBinder.cs
@@ -175,28 +175,33 @@ internal override TypeSymbol GetIteratorElementType(YieldStatementSyntax node, D
             return _iteratorInfo.ElementType;
         }
 
-        private TypeSymbol GetIteratorElementTypeFromReturnType(RefKind refKind, TypeSymbol returnType, CSharpSyntaxNode errorLocationNode, DiagnosticBag diagnostics)
+        internal TypeSymbol GetIteratorElementTypeFromReturnType(RefKind refKind, TypeSymbol returnType, CSharpSyntaxNode errorLocationNode, DiagnosticBag diagnostics)
+        {
+            return GetIteratorElementTypeFromReturnType(Compilation, binder: this, refKind, returnType, errorLocationNode, diagnostics).TypeSymbol;
+        }
+
+        internal static TypeSymbolWithAnnotations GetIteratorElementTypeFromReturnType(CSharpCompilation compilation, Binder binder, RefKind refKind, TypeSymbol returnType, CSharpSyntaxNode errorLocationNode, DiagnosticBag diagnostics)
         {
             if (refKind == RefKind.None && returnType.Kind == SymbolKind.NamedType)
             {
                 switch (returnType.OriginalDefinition.SpecialType)
                 {
                     case SpecialType.System_Collections_IEnumerable:
                     case SpecialType.System_Collections_IEnumerator:
-                        return GetSpecialType(SpecialType.System_Object, diagnostics, errorLocationNode);
+                        return TypeSymbolWithAnnotations.Create(binder.GetSpecialType(SpecialType.System_Object, diagnostics, errorLocationNode));
 
                     case SpecialType.System_Collections_Generic_IEnumerable_T:
                     case SpecialType.System_Collections_Generic_IEnumerator_T:
-                        return ((NamedTypeSymbol)returnType).TypeArgumentsNoUseSiteDiagnostics[0].TypeSymbol;
+                        return ((NamedTypeSymbol)returnType).TypeArgumentsNoUseSiteDiagnostics[0];
                 }
 
-                if (returnType.OriginalDefinition == Compilation.GetWellKnownType(WellKnownType.System_Collections_Generic_IAsyncEnumerable_T))
+                if (returnType.OriginalDefinition == compilation.GetWellKnownType(WellKnownType.System_Collections_Generic_IAsyncEnumerable_T))
                 {
-                    return ((NamedTypeSymbol)returnType).TypeArgumentsNoUseSiteDiagnostics[0].TypeSymbol;
+                    return ((NamedTypeSymbol)returnType).TypeArgumentsNoUseSiteDiagnostics[0];
                 }
             }
 
-            return null;
+            return default;
         }
 
         internal override void LookupSymbolsInSingleBinder(

diff --git a/src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs b/src/Compilers/CSharp/Portable/FlowAnalysis/NullableWalker.cs
@@ -4601,29 +4601,13 @@ public override BoundNode VisitYieldReturnStatement(BoundYieldReturnStatement no
             }
             var method = (MethodSymbol)_member;
             Debug.Assert(method.IsIterator);
-            VisitOptionalImplicitConversion(expr, getIteratorElementType(method.ReturnType.TypeSymbol), useLegacyWarnings: false, AssignmentKind.Return);
-            return null;
-
-            TypeSymbolWithAnnotations getIteratorElementType(TypeSymbol returnType)
-            {
-                switch (returnType.OriginalDefinition.SpecialType)
-                {
-                    case SpecialType.System_Collections_IEnumerable:
-                    case SpecialType.System_Collections_IEnumerator:
-                        return TypeSymbolWithAnnotations.Create(compilation.GetSpecialType(SpecialType.System_Object));
 
-                    case SpecialType.System_Collections_Generic_IEnumerable_T:
-                    case SpecialType.System_Collections_Generic_IEnumerator_T:
-                        return ((NamedTypeSymbol)returnType).TypeArgumentsNoUseSiteDiagnostics[0];
-                }
+            var ignored = DiagnosticBag.GetInstance();
+            var elementType = InMethodBinder.GetIteratorElementTypeFromReturnType(compilation, _binder, RefKind.None, method.ReturnType.TypeSymbol, (CSharpSyntaxNode)node.Syntax, ignored);
+            ignored.Free();
 
-                if (returnType.OriginalDefinition == compilation.GetWellKnownType(WellKnownType.System_Collections_Generic_IAsyncEnumerable_T))
-                {
-                    return ((NamedTypeSymbol)returnType).TypeArgumentsNoUseSiteDiagnostics[0];
-                }
-
-                return default;
-            }
+            VisitOptionalImplicitConversion(expr, elementType, useLegacyWarnings: false, AssignmentKind.Return);
+            return null;
         }
 
 #endregion Visitors