Interpreter: handle inlined call that returns self for structs (#12259)

spec/compiler/interpreter/structs_spec.cr

@@ -338,5 +338,30 @@ describe Crystal::Repl::Interpreter do
         f.x + f.y + f.z
       CODE
     end
+
+    it "inlines struct method that returns self (#12253)" do
+      interpret(<<-CODE).should eq(42)
+        struct Foo
+          def initialize(@x : Int32)
+          end
+
+          def x
+            @x
+          end
+
+          def foo
+            me
+          end
+
+          def me
+            self
+          end
+        end
+
+        a = Foo.new(42)
+        b = a.foo
+        b.x
+      CODE
+    end
   end
 end

src/compiler/crystal/interpreter/compiler.cr

@@ -1773,7 +1773,12 @@ class Crystal::Repl::Compiler < Crystal::Visitor
         if obj
           request_value(obj)
         else
-          put_self(node: node)
+          if scope.struct? && scope.passed_by_value?
+            # Load the entire self from the pointer that's self
+            get_self_ivar 0, aligned_sizeof_type(scope), node: node
+          else
+            put_self(node: node)
+          end
         end
       end