Add analysis suite

CHANGELOG.md

@@ -27,3 +27,5 @@
 - Add additional overloads for `Result<T>.Equals` which allow specifying an equality comparer to use for comparing values.
 
 - Rename `GetValueOrDefault(T @default)` and `GetValueOrDefault(Func<T> getDefault)` to `GetValueOr`.
+
+- Add analyzer and code-fix suite.

Rascal.sln

@@ -1,41 +1,55 @@
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src/Rascal.Analysis.Tests/Analyzers/ToSusTypeAnalyzerTests.cs

@@ -0,0 +1,164 @@
+using VerifyCS = Rascal.Analysis.Tests.Verifiers.AnalyzerVerifier<Rascal.Analysis.Analyzers.ToSusTypeAnalyzer>;
+
+namespace Rascal.Analysis.Analyzers.Tests;
+
+public class ToSusTypeAnalyzerTests
+{
+    [Fact]
+    public async Task Reports_SameType_OnSameType() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var x = Ok(2);
+            var r = x.To<{|RASCAL004:int|}>();
+        }
+    }
+    """);
+
+    [Fact]
+    public async Task Reports_ImpossibleType_OnBothStructTypes() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var x = Ok(2);
+            var r = x.To<{|RASCAL005:bool|}>();
+        }
+    }
+    """);
+
+    [Fact]
+    public async Task Reports_ImpossibleType_OnBothClassTypes_OutsideHierarchy() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var x = Ok(new B());
+            var r = x.To<{|RASCAL005:C|}>();
+        }
+    }
+
+    class A {}
+    class B : A {}
+    class C : A {}
+    """);
+
+    [Fact]
+    public async Task DoesNotReport_OnBothClassTypes_InsideHierarchy_Up() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var x = Ok(new B());
+            var r = x.To<A>();
+        }
+    }
+
+    class A {}
+    class B : A {}
+    """);
+
+    [Fact]
+    public async Task DoesNotReport_OnBothClassTypes_InsideHierarchy_Down() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var x = Ok(new A());
+            var r = x.To<B>();
+        }
+    }
+
+    class A {}
+    class B : A {}
+    """);
+
+    [Fact]
+    public async Task DoesNotReport_OnFromInterfaceType() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var x = Err<I>("error");
+            var r = x.To<int>();
+        }
+    }
+
+    interface I {}
+    """);
+
+    [Fact]
+    public async Task DoesNotReport_OnToInterfaceType() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var x = Ok(2);
+            var r = x.To<I>();
+        }
+    }
+
+    interface I {}
+    """);
+
+    [Fact]
+    public async Task DoesNotReport_OnFromTypeParameter() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar<T>()
+        {
+            var x = Err<T>("error");
+            var r = x.To<int>();
+        }
+    }
+    """);
+
+    [Fact]
+    public async Task DoesNotReport_OnToTypeParameter() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar<T>()
+        {
+            var x = Ok(2);
+            var r = x.To<T>();
+        }
+    }
+    """);
+}

src/Rascal.Analysis.Tests/Analyzers/UnnecessaryIdMapAnalyzerTests.cs

@@ -0,0 +1,38 @@
+using VerifyCS = Rascal.Analysis.Tests.Verifiers.AnalyzerVerifier<Rascal.Analysis.Analyzers.UnnecessaryIdMapAnalyzer>;
+
+namespace Rascal.Analysis.Analyzers.Tests;
+
+public class UnnecessaryIdMapAnalyzerTests
+{
+    [Fact]
+    public async Task DoesNotReport_OnMapOperationCall() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var result = Ok(2);
+            var v = result.Map(x => x + 1);
+        }
+    }
+    """);
+
+    [Fact]
+    public async Task Reports_OnMapIdCall() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var result = Ok(2);
+            var v = result.{|RASCAL003:Map(x => x)|};
+        }
+    }
+    """);
+}

src/Rascal.Analysis.Tests/Analyzers/UseGetValueOrForIdMatchAnalyzerTests.cs

@@ -0,0 +1,38 @@
+using VerifyCS = Rascal.Analysis.Tests.Verifiers.AnalyzerVerifier<Rascal.Analysis.Analyzers.UseGetValueOrForIdMatchAnalyzer>;
+
+namespace Rascal.Analysis.Analyzers.Tests;
+
+public class UseGetValueOrForIdMatchAnalyzerTests
+{
+    [Fact]
+    public async Task DoesNotReport_OnOperation() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var r = Ok(2);
+            var x = r.Match(x => x + 1, _ => 0);
+        }
+    }
+    """);
+
+    [Fact]
+    public async Task Reports_OnId() => await VerifyCS.VerifyAnalyzerAsync("""
+    using System;
+    using Rascal;
+    using static Rascal.Prelude;
+
+    public static class Foo
+    {
+        public static void Bar()
+        {
+            var r = Ok(2);
+            var x = r.{|RASCAL006:Match|}(x => x, _ => 0);
+        }
+    }
+    """);
+}