Merge pull request #39465 from alrz/fix-if-to-switch

Fix minor issue in IfToSwitch refactoring

src/EditorFeatures/CSharpTest/CodeActions/ConvertIfToSwitch/ConvertIfToSwitchTests.cs

@@ -70,6 +70,87 @@ void M(int i)
 }");
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsConvertIfToSwitch)]
+        public async Task TestMissingOnSubsequentBlock()
+        {
+            await TestMissingInRegularAndScriptAsync(
+@"class C
+{
+    int M(int i)
+    {
+        [||]if (i == 3) return 0;
+        { if (i == 6) return 1; }
+        return 2;
+    }
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsConvertIfToSwitch)]
+        public async Task TestElseBlock_01()
+        {
+            await TestInRegularAndScriptAsync(
+@"class C
+{
+    int M(int i)
+    {
+        [||]if (i == 3) return 0;
+        else { if (i == 6) return 1; }
+    }
+}",
+@"class C
+{
+    int M(int i)
+    {
+        switch (i)
+        {
+            case 3:
+                return 0;
+            case 6:
+                return 1;
+        }
+    }
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsConvertIfToSwitch)]
+        public async Task TestElseBlock_02()
+        {
+            await TestInRegularAndScriptAsync(
+@"class C
+{
+    int M(int i)
+    {
+        [||]if (i == 3)
+        {
+            return 0;
+        }
+        else
+        {
+            if (i == 6) return 1;
+            if (i == 7) return 1;
+            return 0;
+        }
+    }
+}",
+@"class C
+{
+    int M(int i)
+    {
+        switch (i)
+        {
+            case 3:
+                return 0;
+            case 6:
+                return 1;
+            case 7:
+                return 1;
+            default:
+                return 0;
+        }
+    }
+}");
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsConvertIfToSwitch)]
         public async Task TestMultipleCases_01()
         {
@@ -595,6 +676,33 @@ int M(int? i)
 }", index: 1);
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsConvertIfToSwitch)]
+        public async Task TestSwitchExpression_02()
+        {
+            await TestInRegularAndScriptAsync(
+@"class C
+{
+    int M(int? i)
+    {
+        [||]if (i == null) { return 5; }
+        if (i == 0) { return 6; }
+        else { return 7; }
+    }
+}",
+@"class C
+{
+    int M(int? i)
+    {
+        return i switch
+        {
+            null => 5,
+            0 => 6,
+            _ => 7
+        };
+    }
+}", index: 1);
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsConvertIfToSwitch)]
         public async Task TestSubsequentIfStatements_02()
         {
@@ -706,7 +814,7 @@ int M(int i)
         [||]if (i == 10) return 5;
         if (i == 20) return 6;
         if (i == i) return 0;
-        reuturn 7;
+        return 7;
     }
 }",
 @"class C
@@ -721,7 +829,7 @@ int M(int i)
                 return 6;
         }
         if (i == i) return 0;
-        reuturn 7;
+        return 7;
     }
 }");
         }
@@ -746,7 +854,7 @@ int M(int i)
         {
             return 0;
         }
-        reuturn 7;
+        return 7;
     }
 }",
 @"class C
@@ -764,7 +872,7 @@ int M(int i)
         {
             return 0;
         }
-        reuturn 7;
+        return 7;
     }
 }");
         }
@@ -798,7 +906,7 @@ int M(int i)
         {
             return 0;
         }
-        reuturn 7;
+        return 7;
     }
 }",
 @"class C
@@ -825,7 +933,7 @@ int M(int i)
         {
             return 0;
         }
-        reuturn 7;
+        return 7;
     }
 }");
         }

src/Features/Core/Portable/ConvertIfToSwitch/AbstractConvertIfToSwitchCodeRefactoringProvider.Analyzer.cs

@@ -26,9 +26,9 @@ internal abstract partial class AbstractConvertIfToSwitchCodeRefactoringProvider
         //
         //    <if-statement>
         //        : if (<section-expr>) { _ } else <if-statement>
+        //        | if (<section-expr>) { _ } else { <if-statement-sequence> }
         //        | if (<section-expr>) { _ } else { _ }
         //        | if (<section-expr>) { _ }
-        //        | { <if-statement-sequence> }
         //
         //    <section-expr>
         //        : <section-expr> || <pattern-expr>
@@ -131,17 +131,14 @@ private bool ParseIfStatementSequence(ReadOnlySpan<IOperation> operations, Array
             //
             //    <if-statement>
             //        : if (<section-expr>) { _ } else <if-statement>
+            //        | if (<section-expr>) { _ } else { <if-statement-sequence> }
             //        | if (<section-expr>) { _ } else { _ }
             //        | if (<section-expr>) { _ }
-            //        | { <if-statement-sequence> }
             //
             private bool ParseIfStatement(IOperation operation, ArrayBuilder<AnalyzedSwitchSection> sections, out IOperation? defaultBodyOpt)
             {
                 switch (operation)
                 {
-                    case IBlockOperation op:
-                        return ParseIfStatementSequence(op.Operations.AsSpan(), sections, out defaultBodyOpt);
-
                     case IConditionalOperation op when CanConvert(op):
                         var section = ParseSwitchSection(op);
                         if (section is null)
@@ -155,7 +152,7 @@ private bool ParseIfStatement(IOperation operation, ArrayBuilder<AnalyzedSwitchS
                         {
                             defaultBodyOpt = null;
                         }
-                        else if (!ParseIfStatement(op.WhenFalse, sections, out defaultBodyOpt))
+                        else if (!ParseIfStatementOrBlock(op.WhenFalse, sections, out defaultBodyOpt))
                         {
                             defaultBodyOpt = op.WhenFalse;
                         }
@@ -167,6 +164,13 @@ private bool ParseIfStatement(IOperation operation, ArrayBuilder<AnalyzedSwitchS
                 return false;
             }
 
+            private bool ParseIfStatementOrBlock(IOperation op, ArrayBuilder<AnalyzedSwitchSection> sections, out IOperation? defaultBodyOpt)
+            {
+                return op is IBlockOperation block
+                    ? ParseIfStatementSequence(block.Operations.AsSpan(), sections, out defaultBodyOpt)
+                    : ParseIfStatement(op, sections, out defaultBodyOpt);
+            }
+
             private AnalyzedSwitchSection? ParseSwitchSection(IConditionalOperation operation)
             {
                 var labels = ArrayBuilder<AnalyzedSwitchLabel>.GetInstance();