Added a repro

tests/EntityFrameworkCore.Projectables.Generator.Tests/ProjectionExpressionGeneratorTests.InheritedMembers.received.txt

@@ -0,0 +1,18 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using EntityFrameworkCore.Projectables;
+using Foo;
+
+namespace EntityFrameworkCore.Projectables.Generated
+#nullable disable
+{
+    public static class Foo_Bar_ProjectedId
+    {
+        public static System.Linq.Expressions.Expression<System.Func<global::Foo.Bar, int>> Expression()
+        {
+            return (global::Foo.Bar @this) => 
+                Id;
+        }
+    }
+}

tests/EntityFrameworkCore.Projectables.Generator.Tests/ProjectionExpressionGeneratorTests.InheritedMembers.verified.txt

@@ -0,0 +1,18 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using EntityFrameworkCore.Projectables;
+using Foo;
+
+namespace EntityFrameworkCore.Projectables.Generated
+#nullable disable
+{
+    public static class Foo_Bar_ProjectedId
+    {
+        public static System.Linq.Expressions.Expression<System.Func<global::Foo.Bar, int>> Expression()
+        {
+            return (global::Foo.Bar @this) => 
+                @this.Id;
+        }
+    }
+}

tests/EntityFrameworkCore.Projectables.Generator.Tests/ProjectionExpressionGeneratorTests.cs

@@ -959,6 +959,35 @@ namespace Foo {
             return Verifier.Verify(result.GeneratedTrees[0].ToString());
         }
 
+        [Fact]
+        public Task InheritedMembers()
+        {
+            var compilation = CreateCompilation(@"
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using EntityFrameworkCore.Projectables;
+
+namespace Foo {
+    public class Foo {
+        public int Id { get; set; }
+    }
+
+    public class Bar : Foo {
+        [Projectable]
+        public int ProjectedId => Id;
+    }
+}
+");
+
+            var result = RunGenerator(compilation);
+
+            Assert.Empty(result.Diagnostics);
+            Assert.Single(result.GeneratedTrees);
+
+            return Verifier.Verify(result.GeneratedTrees[0].ToString());
+        }
+
         #region Helpers
 
         Compilation CreateCompilation(string source, bool expectedToCompile = true)