jurgenvinju · Oct 12, 2026 · Oct 12, 2026 · Oct 12, 2026 · Oct 12, 2026 · Oct 12, 2026
diff --git a/blog/2026-10-12-no-more-annotations.md b/blog/2026-10-12-no-more-annotations.md
@@ -0,0 +1,42 @@
+---
+title: Final step in replacing the annotations feature with the keyword field feature
+authors: [jvinju]
+---
+
+Over the years we have been gradually replacing the [Annotation](/docs/Rascal/Declarations/Annotation) feature with the [Keyword field](/docs/Rascal/Declarations/AlgebraicDataType) feature.
+In [release 0.43.0](/release-notes/rascal-0-43-x-release-notes) the final step has been made by replacing the semantics of annotations with a "not implemented" error message with a **quick-fix** suggestion.
+This feature removal went through the following stages to make for a smooth transition:
+
+1. `2009-2013` only annotations implemented (syntax and semantics).
+2. `2013-2019` both annotations and keyword fields implemented (syntax and semantics), but never at the same time on the same node.
+3. `2019-2026` annotations simulated by keyword fields (both the syntactical features use semantics of keyword fields); `Tree@\loc` is simulated by `Tree.src`.
+4. `2026-....` annotations not implemented anymore (only syntax), everything is a keyword field. `anno loc Tree@\loc` is replaced by `data Tree(loc src=|unknown:///|)` in the `ParseTree` module.
+
+We are now past step 4. Every use of a syntactic construct related to annotations will produce:
+1. an error message by the checker.
+2. a quick-fix suggestion to remove any and all uses of annotation syntax _in the current project_ and replace them by the respective keyword field feature.
+3. a static error by the interpreter.
+
+Note that:
+* If you don't fix the code, it will not run anymore and you will get static exceptions by the interpreter.
+* After you have fixed the code, it may not run properly on older versions of Rascal anymore, because older versions always come with their own version of the `ParseTree` module.
+
+For your convenience we list the differences in syntax and semantics here:
+
+| Feature | Annotations | Keyword fields | Note |
+|  --- | --- | ---- | --- |
+| declaration | `anno OfType OnType@name` | `data OnType(OfType name = Default)` | annotations do not have default expressions |
+| projection  | `OnExpr@name`             | `OnExpr.name`                        | annotations throw `NoSuchAnnotation` if `name` does not exist, while keyword fields return their default. Keyword fields on `node` throw `NoSuchField` exceptions and return a value of type `value` always. |
+| assignment | `OnExpr@name = Expr` | `OnExpr.name = Expr` | Assigment operators like `+=` also inherit the semantics of projection |
+| update  | `OnExpr[@name=Expr]` | `OnExpr[name=Expr]` | field update works the same for both features, both set the field whether or not it was there before |
+| equality | `Cons[@f=1] == Cons[@f=2]` is `true` | `Cons(f=1) == Cons(f=2)` is `false` | constructor equality ignores annotations while it does not ignore keyword fields, this also holds for set elements, and map/relation keys |
+| matching | `Cons[@f=1] := Cons[@f=2]` is `true` |  `Cons(f=1) := Cons(f=2)` is `true` | constructor matching always ignores keyword fields and annotations |
+
+In stage 3, annotations took the semantics of keyword fields for _declaration_, _assignment_ and _matching_, and _equality_ while for _projection_ still the old `NoSuchAnnotation` was thrown. This is the stage you have probably been using. The hard change was between stages 2 and 3.
+
+The quickfix for stage 4 produces an arbitrary default for well known types,
+i.e. `int age = 0`, while for more complex type an exception is thrown by the default expression. It is advised to review the defaults manually.
+
+Finally, the quickfix may open and rewrite a large group of files for the current project. You have to save and close each of them manually to write the result to disk. This would also be a good time to review the generated defaults.
+
+If you get stuck, please contact (Jurgen Vinju)[mailto:Jurgen.Vinju@cwi.nl] or (Davy Landman)[mailto:Davy.Landman@swat.engineering] for help.
diff --git a/blog/authors.yml b/blog/authors.yml
@@ -1,6 +1,6 @@
 jvinju:
   name: Jurgen Vinju
-  title: Senior Researcher @ CWI-SWAT, professor @ TU/E, Rascal Core Team
+  title: Senior Researcher @ CWI-SWAT, Rascal Core Team
   url: http://homepages.cwi.nl/~jurgenv
   image_url: /images/authors/jurgen.jpg
 

diff --git a/courses/Rascal/Declarations/Annotation/Annotation.md b/courses/Rascal/Declarations/Annotation/Annotation.md
@@ -4,13 +4,15 @@ keywords:
   - anno
   - attributes
   - decorations
+  - keyword field
   - "@"
 
 ---
 
 #### Synopsis
 
-Declare an annotation type for nodes. This feature is deprecated; please use [keyword fields]((AlgebraicDataType)) instead.
+Declare an annotation type for nodes. This feature has been removed; please use [keyword fields]((AlgebraicDataType)) instead.
+See [blog](/blog/2026/10/12/no-more-annotations).
 
 #### Syntax
 
@@ -22,35 +24,8 @@ Declare an annotation type for nodes. This feature is deprecated; please use [ke
 
 #### Description
 
-An annotation may be associated with any node value, be it a pure node or some ((Algebraic Data Type)) derived from it.
-
-Annotations are intended to attach application data to values,
-like adding position information or control flow information to source code or adding visualization information to a graph.
-
-An annotation declaration defines:
-
-*  _AnnoType_, the type of the annotation values,
-*  _OnType_, the type of the values that are being annotated,
-*  _Name_, the name of the annotation.
-
-
-Any value of any named type can be annotated and the type of these annotations can be declared precisely.
-
-The following constructs are provided for handling annotations:
-
-*  `Val @ Anno`: is an expression that retrieves the value of annotation _Anno_ of value _Val_ (may be undefined!). 
-
-*  `Val~1~[@Anno = Val~2~]`: is an expression that sets the value of annotation _Anno_ of the value _Val~1~_ to _Val~2~_
-   and returns _Val~1~_ with the new annotation value as result. 
-
-*  `Var @ Anno = Val`: is an assignment statement that sets the value of annotation _Anno_ of the value of variable _Var_ to _Val_.
-
 #### Examples
 
-Examples have been removed since this feature is deprecated. 
-
 #### Benefits
 
 #### Pitfalls
-
-* Annotations are cumbersome since they change the structure of ((Values)) without changing the semantics of the identity of a value. This is why they are deprecated.
diff --git a/...es/Rascal/Errors/CompileTimeErrors/UndeclaredAnnotation/UndeclaredAnnotation.md b/...es/Rascal/Errors/CompileTimeErrors/UndeclaredAnnotation/UndeclaredAnnotation.md
diff --git a/...cal/Errors/RunTimeErrors/RuntimeExceptions/NoSuchAnnotation/NoSuchAnnotation.md b/...cal/Errors/RunTimeErrors/RuntimeExceptions/NoSuchAnnotation/NoSuchAnnotation.md
diff --git a/courses/Rascal/Statements/Assignment/Annotation/Annotation.md b/courses/Rascal/Statements/Assignment/Annotation/Annotation.md
@@ -8,7 +8,8 @@ keywords:
 
 #### Synopsis
 
-Assign to an annotation. This feature is deprecated.
+Assign to an annotation. This feature has been removed.
+See [this blog](/blog/2026/10/12/no-more-annotations).
 
 #### Syntax
 
@@ -20,14 +21,9 @@ Assign to an annotation. This feature is deprecated.
 
 #### Description
 
-The value _V_ of _Assignable_ is determined and should be of a type that has an annotation _Name_.
-A new value _V_' is created that is a copy of _V_ but with the value of annotation _Name_ replaced by the value of _Exp_.
-_V_' is assigned to _Assignable_.
-See ((Declarations-Annotation)).
 
 #### Examples
 
-Examples have been removed since this feature is deprecated.
 
 #### Benefits
 

diff --git a/courses/Rascal/Statements/Assignment/Assignment.md b/courses/Rascal/Statements/Assignment/Assignment.md
@@ -12,7 +12,7 @@ keywords:
   - "]"
   - "."
   - "?"
-  - "@"
+  - deconstructing bind
 
 ---
 
@@ -35,7 +35,6 @@ An _Assignable_ is one of the following:
 *   `Assignable . Name` 
 *   `< Assignable, Assignable, ..., Assignable >`
 *   `Assignable ? Exp` 
-*   `Assignable @ Name`
 *   `Name ( Assignable, Assignable, ... )`
 
 #### Types

diff --git a/release-notes/rascal-0-43-x-release-notes.md b/release-notes/rascal-0-43-x-release-notes.md
@@ -1,7 +1,7 @@
 ---
 authors: [sungshik]
 title: "Rascal 0.43.x release notes"
-sidebar_position: 87
+sidebar_position: 85
 ---
 
 In this post we report on the Rascal release 0.43.x
@@ -23,11 +23,16 @@ The Java-air project was extracted from the Rascal standard library in version 0
 * The `std` scheme to refer to locations in the standard library has been sunsetted. See the separate [blog post](/blog/2026/10/08/removed-library-schemes) for details. ([#2828](https://github.com/usethesource/rascal/pull/2828), [#2847](https://github.com/usethesource/rascal/pull/2847))
 * The scheme and authority of locations are now case-insensitive (normalized to lowercase), as required by the [URI RFC](https://datatracker.ietf.org/doc/html/rfc3986). This fixes a few subtle issues when locations were used in combination with some form of RPC (HTTP/JSON/LSP) or case-sensitive file system. ([#2845](https://github.com/usethesource/rascal/pull/2845), [#2857](https://github.com/usethesource/rascal/pull/2857), [#2851](https://github.com/usethesource/rascal/pull/2851), [#2860](https://github.com/usethesource/rascal/pull/2860), [#2862](https://github.com/usethesource/rascal/pull/2862))
 * Parsers (including concrete syntax pattern matchers) can now be run directly for symbols with regular operators, including `*`, `+`, and `?`, without the need to introduce dummy symbols in the grammar. ([#2809](https://github.com/usethesource/rascal/pull/2809))
-* Annotations have been removed. A Quick Fix is available in VS Code to automatically migrate all Rascal code with annotations to equivalent code without them. ([#1974](https://github.com/usethesource/rascal/pull/1974), [#2793](https://github.com/usethesource/rascal/pull/2793))
+* Annotation syntax and semantics have been removed. See [blog post](/blog/2026/10/12/no-more-annotations). A Quick Fix is available in VS Code to automatically migrate all Rascal code with annotations to equivalent code (keyword fields). ([#1974](https://github.com/usethesource/rascal/pull/1974), [#2793](https://github.com/usethesource/rascal/pull/2793))
 * The Rascal language now depends on version 1.1.x of Vallang.
 
 :::info
-The removal of the `std` scheme, the removal of annotation support, and the case-insensitivity of scheme/authority are low-impact breaking changes. Migration tools and Quick Fixes in the VS Code extension are provided to streamline the few code changes that might be needed.
+The removal of the `std` scheme, the removal of annotation support, and the case-insensitivity of scheme/authority are low-impact breaking changes. Migration tools and Quick Fixes in the VS Code extension are provided to streamline the few code changes that might be needed. 
+:::
+
+:::info
+If you have string constants in your own Java code for location schemes, changing these to all lowercase will help prevent any issues. For example,
+change `String myScheme = "arrayLength";` to `String myScheme = "arraylength";`, to make sure that `myLoc.getScheme().equals(myScheme)` still works.
 :::
 
 ### Maven and evaluator improvements