Use ordinal comparisons in `ExpressionTextCache`

- #6349
- C# field and property names are case-sensitive
  - it's not important (where this cache is used) that HTML field names are case-insenstive

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Internal/ExpressionTextCache.cs

@@ -70,7 +70,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                                 return true;
                             }
 
-                            if (!string.Equals(memberName1, memberName2, StringComparison.OrdinalIgnoreCase))
+                            if (!string.Equals(memberName1, memberName2, StringComparison.Ordinal))
                             {
                                 return false;
                             }
@@ -108,7 +108,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                             break;
                         }
 
-                        hashCodeCombiner.Add(memberName, StringComparer.OrdinalIgnoreCase);
+                        hashCodeCombiner.Add(memberName, StringComparer.Ordinal);
                         expression = memberExpression.Expression;
                     }
                     else

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Internal/ExpressionHelperTest.cs

@@ -39,6 +39,10 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                         (Expression<Func<TestModel, int>>)(testModel => testModel.SelectedCategory.CategoryId),
                         "SelectedCategory.CategoryId"
                     },
+                    {
+                        (Expression<Func<LowerModel, int>>)(testModel => testModel.selectedcategory.CategoryId),
+                        "selectedcategory.CategoryId"
+                    },
                     {
                         (Expression<Func<TestModel, string>>)(model => model.SelectedCategory.CategoryName.MainCategory),
                         "SelectedCategory.CategoryName.MainCategory"
@@ -71,6 +75,10 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                         (Expression<Func<IList<TestModel>, Category>>)(model => model[i].SelectedCategory),
                         "[3].SelectedCategory"
                     },
+                    {
+                        (Expression<Func<IList<LowerModel>, Category>>)(model => model[i].selectedcategory),
+                        "[3].selectedcategory"
+                    },
                     {
                         (Expression<Func<IDictionary<string, TestModel>, string>>)(model => model[key].SelectedCategory.CategoryName.MainCategory),
                         "[TestModel].SelectedCategory.CategoryName.MainCategory"
@@ -87,10 +95,18 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                         (Expression<Func<IList<TestModel>, int>>)(model => model[2].PreferredCategories[i].CategoryId),
                         "[2].PreferredCategories[3].CategoryId"
                     },
+                    {
+                        (Expression<Func<IList<LowerModel>, int>>)(model => model[2].preferredcategories[i].CategoryId),
+                        "[2].preferredcategories[3].CategoryId"
+                    },
                     {
                         (Expression<Func<IList<TestModel>, string>>)(model => model.FirstOrDefault().Name),
                         "Name"
                     },
+                    {
+                        (Expression<Func<IList<LowerModel>, string>>)(model => model.FirstOrDefault().name),
+                        "name"
+                    },
                     {
                         (Expression<Func<IList<TestModel>, string>>)(model => model.FirstOrDefault().Model),
                         "Model"
@@ -285,10 +301,22 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                         (Expression<Func<TestModel, Category>>)(model => model.SelectedCategory),
                         (Expression<Func<TestModel, CategoryName>>)(model => model.SelectedCategory.CategoryName)
                     },
+                    {
+                        (Expression<Func<TestModel, CategoryName>>)(model => model.SelectedCategory.CategoryName),
+                        (Expression<Func<LowerModel, CategoryName>>)(model => model.selectedcategory.CategoryName)
+                    },
                     {
                         (Expression<Func<TestModel, string>>)(model => model.Model),
                         (Expression<Func<TestModel, string>>)(model => model.Name)
                     },
+                    {
+                        (Expression<Func<TestModel, string>>)(model => model.Model),
+                        (Expression<Func<LowerModel, string>>)(model => model.model)
+                    },
+                    {
+                        (Expression<Func<TestModel, string>>)(model => model.Name),
+                        (Expression<Func<LowerModel, string>>)(model => model.name)
+                    },
                     {
                         (Expression<Func<TestModel, CategoryName>>)(model => model.SelectedCategory.CategoryName),
                         (Expression<Func<TestModel, string>>)(model => value)
@@ -301,6 +329,10 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                         (Expression<Func<IList<TestModel>, Category>>)(model => model[2].SelectedCategory),
                         (Expression<Func<TestModel, string>>)(model => model.SelectedCategory.CategoryName.MainCategory)
                     },
+                    {
+                        (Expression<Func<IList<TestModel>, Category>>)(model => model[2].SelectedCategory),
+                        (Expression<Func<IList<LowerModel>, Category>>)(model => model[2].selectedcategory)
+                    },
                     {
                         (Expression<Func<TestModel, int>>)(testModel => testModel.SelectedCategory.CategoryId),
                         (Expression<Func<TestModel, Category>>)(model => model.SelectedCategory)
@@ -309,6 +341,10 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                         (Expression<Func<IDictionary<string, TestModel>, string>>)(model => model[key].SelectedCategory.CategoryName.MainCategory),
                         (Expression<Func<TestModel, Category>>)(model => model.SelectedCategory)
                     },
+                    {
+                        (Expression<Func<IDictionary<string, TestModel>, string>>)(model => model[key].SelectedCategory.CategoryName.MainCategory),
+                        (Expression<Func<IDictionary<string, LowerModel>, string>>)(model => model[key].selectedcategory.CategoryName.MainCategory)
+                    },
                     {
                         (Expression<Func<TestModel, string>>)(m => Model),
                         (Expression<Func<TestModel, string>>)(m => m.Model)
@@ -408,6 +444,17 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             public IList<Category> PreferredCategories { get; set; }
         }
 
+        private class LowerModel
+        {
+            public string name { get; set; }
+
+            public string model { get; set; }
+
+            public Category selectedcategory { get; set; }
+
+            public IList<Category> preferredcategories { get; set; }
+        }
+
         private class Category
         {
             public int CategoryId { get; set; }