Consistent exception on empty block expression

Fixes #3882 Fixes #3908
JonHanna · Oct 16, 2015 · 4452dec · 4452dec
1 parent c9c79fe
commit 4452dec
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Showing 3 changed files with 16 additions and 39 deletions.
diff --git a/src/System.Linq.Expressions/src/System/Linq/Expressions/BlockExpression.cs b/src/System.Linq.Expressions/src/System/Linq/Expressions/BlockExpression.cs
@@ -845,7 +845,7 @@ public static BlockExpression Block(IEnumerable<ParameterExpression> variables,
             }
 
             var expressionList = expressions.ToReadOnly();
-            return BlockCore(expressionList.Last().Type, variableList, expressionList);
+            return BlockCore(null, variableList, expressionList);
         }
 
         /// <summary>
@@ -887,29 +887,30 @@ private static BlockExpression BlockCore(Type type, ReadOnlyCollection<Parameter
             RequiresCanRead(expressionList, "expressions");
             ValidateVariables(variableList, "variables");
 
-            Expression last = expressionList.Last();
-            if (type != typeof(void))
+            if (type != null)
             {
-                if (!TypeUtils.AreReferenceAssignable(type, last.Type))
+                Expression last = expressionList.Last();
+                if (type != typeof(void))
                 {
-                    throw Error.ArgumentTypesMustMatch();
+                    if (!TypeUtils.AreReferenceAssignable(type, last.Type))
+                    {
+                        throw Error.ArgumentTypesMustMatch();
+                    }
+                }
+
+                if (!TypeUtils.AreEquivalent(type, last.Type))
+                {
+                    return new ScopeWithType(variableList, expressionList, type);
                 }
             }
 
-            if (!TypeUtils.AreEquivalent(type, last.Type))
+            if (expressionList.Count == 1)
             {
-                return new ScopeWithType(variableList, expressionList, type);
+                return new Scope1(variableList, expressionList[0]);
             }
             else
             {
-                if (expressionList.Count == 1)
-                {
-                    return new Scope1(variableList, expressionList[0]);
-                }
-                else
-                {
-                    return new ScopeN(variableList, expressionList);
-                }
+                return new ScopeN(variableList, expressionList);
             }
         }
 

diff --git a/src/System.Linq.Expressions/tests/Block/NoParameterBlockTests.cs b/src/System.Linq.Expressions/tests/Block/NoParameterBlockTests.cs
@@ -206,7 +206,6 @@ public void NullExpressionList()
         [Theory]
         [MemberData("BlockSizes")]
         [ActiveIssue(3909)]
-        [ActiveIssue(3908)]
         public void NullExpressionInExpressionList(int size)
         {
             List<Expression> expressionList = Enumerable.Range(0, size).Select(i => (Expression)Expression.Constant(1)).ToList();
@@ -332,7 +331,6 @@ public void EmptyBlockNotAllowed()
         }
 
         [Fact]
-        [ActiveIssue(3882)]
         public void EmptyBlockWithParametersNotAllowed()
         {
             Assert.Throws<ArgumentException>("expressions", () => Expression.Block(Enumerable.Repeat<ParameterExpression>(Expression.Parameter(typeof(int)), 1)));
@@ -342,7 +340,6 @@ public void EmptyBlockWithParametersNotAllowed()
         }
 
         // If https://github.com/dotnet/corefx/issues/3043 is ever actioned, this case would still be prohibited.
-
         [Fact]
         public void EmptyBlockWithNonVoidTypeNotAllowed()
         {
@@ -351,7 +348,6 @@ public void EmptyBlockWithNonVoidTypeNotAllowed()
         }
 
         [Fact]
-        [ActiveIssue(3882)]
         public void EmptyBlockWithParametersAndNonVoidTypeNotAllowed()
         {
             Assert.Throws<ArgumentException>("expressions", () => Expression.Block(typeof(int), Enumerable.Repeat<ParameterExpression>(Expression.Parameter(typeof(int)), 1)));

diff --git a/src/System.Linq.Expressions/tests/Block/ParameterBlockTests.cs b/src/System.Linq.Expressions/tests/Block/ParameterBlockTests.cs
@@ -68,7 +68,6 @@ public void NullExpressionList()
 
         [Theory]
         [MemberData("BlockSizes")]
-        [ActiveIssue(3908)]
         public void NullExpressionInExpressionList(int size)
         {
             List<Expression> expressionList = Enumerable.Range(0, size).Select(i => (Expression)Expression.Constant(1)).ToList();
@@ -83,22 +82,6 @@ public void NullExpressionInExpressionList(int size)
             }
         }
 
-        [Theory]
-        [MemberData("BlockSizes")]
-        public void NullExpressionInExpressionListTemp(int size)
-        {
-            List<Expression> expressionList = Enumerable.Range(0, size).Select(i => (Expression)Expression.Constant(1)).ToList();
-            for (int i = 0; i != expressionList.Count; ++i)
-            {
-                Expression[] expressions = expressionList.ToArray();
-                expressions[i] = null;
-                Assert.ThrowsAny<Exception>(() => Expression.Block(SingleParameter, expressions));
-                Assert.ThrowsAny<Exception>(() => Expression.Block(SingleParameter, expressions.Skip(0)));
-                Assert.ThrowsAny<Exception>(() => Expression.Block(typeof(int), SingleParameter, expressions));
-                Assert.ThrowsAny<Exception>(() => Expression.Block(typeof(int), SingleParameter, expressions.Skip(0)));
-            }
-        }
-
         [Theory]
         [MemberData("BlockSizes")]
         public void UnreadableExpressionInExpressionList(int size)
@@ -176,7 +159,6 @@ public void InvalidExpressionIndexVaryingExceptin(object value, int blockSize)
 
         // See https://github.com/dotnet/corefx/issues/3043
         [Fact]
-        [ActiveIssue(3882)]
         public void EmptyBlockWithParametersNotAllowed()
         {
             Assert.Throws<ArgumentException>("expressions", () => Expression.Block(SingleParameter));
@@ -186,9 +168,7 @@ public void EmptyBlockWithParametersNotAllowed()
         }
 
         // If https://github.com/dotnet/corefx/issues/3043 is ever actioned, this case would still be prohibited.
-
         [Fact]
-        [ActiveIssue(3882)]
         public void EmptyBlockWithParametersAndNonVoidTypeNotAllowed()
         {
             Assert.Throws<ArgumentException>("expressions", () => Expression.Block(typeof(int), SingleParameter));