deps: upgrade rowan 0.16 → 0.17 (#1451)

## Summary

Closes #1448.

Upgrade `rowan` from 0.16.1 to **0.17.0** in `assura-parser` and
`assura-fmt`.

### Breaking changes in 0.17 (from upstream)

Rowan 0.17 removed mutable syntax edit APIs (`SyntaxNodeMut` / in-place
tree mutation). Assura only:

- builds green trees via `GreenNodeBuilder` + events
- wraps them with `SyntaxNode::new_root`
- walks immutable `SyntaxNode` / `NodeOrToken` for lowering and
formatting

No call-site code changes were required; compile and tests are green
as-is.

### Docs

AGENTS.md and `docs/INTERNALS.md` version notes updated for 0.17 and the
immutable-only API.

## Test plan

- [x] `cargo check -p assura-parser -p assura-fmt --locked`
- [x] `cargo test -p assura-parser --locked` (lib + integration,
including demos/fixtures snapshots)
- [x] `cargo test -p assura-fmt --locked`
- [x] `cargo test -p assura-types --locked --lib`
- [x] `cargo clippy -p assura-parser -p assura-fmt --locked -- -D
warnings`
- [x] `assura check` demos: libwebp-huffman, heartbleed, showcase-echo
- [ ] CI green

---------

Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>

Author: SebTardif

AGENTS.md

@@ -532,17 +532,25 @@ Keep dependencies up to date. Run `cargo outdated -R` periodically.
 
 | Crate | Version | Notes |
 |-------|---------|-------|
-| rowan | 0.16 | stable, upgrades OK |
+| rowan | 0.17 | immutable CST only (0.17 removed mutable edit APIs; Assura never used them) |
 | ariadne | 0.6 | Report::build takes (kind, span) with 2 args; span is (Id, Range) |
 | logos | 0.16 | stable, upgrades OK |
 | z3 | 0.20 | No lifetime params on AST types; no &ctx first arg; pre-generated FFI bindings |
 | sha2 | 0.11 | Uses digest 0.11, high-level API unchanged |
 | cvc5 | 0.4 | Native FFI bindings; `Sort` not Copy; `Kind` names differ from SMT-LIB2; requires `features = ["static"]` for static linking |
 
-**rowan 0.16 patterns**: `GreenNodeBuilder`, `SyntaxNode::new_root()`,
+**rowan 0.17 patterns**: `GreenNodeBuilder`, `SyntaxNode::new_root()`,
 `Language` trait on `AssuraLanguage`, `SyntaxKind` enum with `From<u16>`.
 The parser uses an events/markers pattern (Open/Close/Advance) with
-Pratt parsing for expressions.
+Pratt parsing for expressions. Rowan 0.17 removed mutable syntax APIs
+(`SyntaxNodeMut` / in-place tree edit); Assura only builds green trees
+and reads them immutably, so no call-site changes were required.
+
+**Downstream crates must not depend on `rowan` directly.** `assura-fmt`
+walks CST children with `as_token()` / `as_node()` only. Matching on
+`rowan::NodeOrToken` while depending on a separate `rowan` crate version
+breaks `cargo package` when crates.io `assura-parser` still pins an
+older rowan (dual type instances). Keep rowan private to `assura-parser`.
 
 **z3 0.20 patterns**: No lifetime params (`Bool`, not `Bool<'ctx>`).
 No `&ctx` first arg on constructors (`Int::from_i64(n)`, not
@@ -665,7 +673,7 @@ These are final. Do not revisit without explicit discussion.
 |----------|--------|-----------|
 | Compiler language | Rust | docs/INVESTIGATION.md |
 | Lexer | logos 0.16 | Fast, derive macro |
-| Parser | rowan 0.16 CST + hand-written recursive descent | Lossless CST, Pratt expressions |
+| Parser | rowan 0.17 CST + hand-written recursive descent | Lossless CST, Pratt expressions |
 | Error display | ariadne 0.6 | Colored spans |
 | SMT solver | Z3 primary (z3 crate), CVC5 fallback | docs/ROADMAP.md |
 | Codegen target | Rust source via prettyplease | NOT syn/quote |

Cargo.lock

@@ -11,4 +11,3 @@ categories.workspace = true
 
 [dependencies]
 assura-parser = { version = "0.4.0", path = "../assura-parser" }
-rowan = "0.16"

crates/assura-fmt/Cargo.toml

@@ -123,18 +123,13 @@ pub fn format_source_file(_file: &assura_parser::ast::SourceFile) -> String {
 // ---------------------------------------------------------------------------
 
 /// Collect all leaf tokens from the CST in document order.
+///
+/// Use `as_token` / `as_node` (not `rowan::NodeOrToken` match arms) so this
+/// crate does not depend on a concrete `rowan` version. Packaging against
+/// crates.io `assura-parser` would otherwise dual-link rowan 0.16 + 0.17.
 fn collect_leaf_tokens(node: &assura_parser::syntax_kind::SyntaxNode) -> Vec<(SyntaxKind, String)> {
     let mut tokens = Vec::new();
-    for child in node.children_with_tokens() {
-        match child {
-            rowan::NodeOrToken::Token(tok) => {
-                tokens.push((tok.kind(), tok.text().to_string()));
-            }
-            rowan::NodeOrToken::Node(n) => {
-                collect_leaf_tokens_into(&n, &mut tokens);
-            }
-        }
-    }
+    collect_leaf_tokens_into(node, &mut tokens);
     tokens
 }
 
@@ -143,13 +138,10 @@ fn collect_leaf_tokens_into(
     tokens: &mut Vec<(SyntaxKind, String)>,
 ) {
     for child in node.children_with_tokens() {
-        match child {
-            rowan::NodeOrToken::Token(tok) => {
-                tokens.push((tok.kind(), tok.text().to_string()));
-            }
-            rowan::NodeOrToken::Node(n) => {
-                collect_leaf_tokens_into(&n, tokens);
-            }
+        if let Some(tok) = child.as_token() {
+            tokens.push((tok.kind(), tok.text().to_string()));
+        } else if let Some(n) = child.as_node() {
+            collect_leaf_tokens_into(n, tokens);
         }
     }
 }

crates/assura-fmt/src/lib.rs

@@ -13,7 +13,7 @@ categories.workspace = true
 assura-ast = { version = "0.4.0", path = "../assura-ast" }
 assura-diagnostics = { version = "0.4.0", path = "../assura-diagnostics" }
 logos = "0.16"
-rowan = "0.16"
+rowan = "0.17"
 
 [dev-dependencies]
 insta = "1"

crates/assura-parser/Cargo.toml

@@ -15,7 +15,7 @@ Source (.assura)
 Lexer (logos 0.16)           crates/assura-parser/src/lexer.rs
   | produces tokens via logos derive
   v
-Parser (rowan 0.16 CST)      crates/assura-parser/src/cst.rs
+Parser (rowan 0.17 CST)      crates/assura-parser/src/cst.rs
   | hand-written recursive descent + Pratt expression parsing
   | produces GreenNode (lossless concrete syntax tree)
   v
@@ -47,7 +47,7 @@ optionally invokes `cargo check` on the generated Rust project.
 
 | Crate | LOC | Tests | Purpose |
 |-------|-----|-------|---------|
-| `assura-parser` | 8,100 | 149 | Lexer (logos 0.16), CST (rowan 0.16), recursive descent parser, Pratt expressions, CST-to-AST lowering |
+| `assura-parser` | 8,100 | 149 | Lexer (logos 0.16), CST (rowan 0.17), recursive descent parser, Pratt expressions, CST-to-AST lowering |
 | `assura-resolve` | 4,300 | 91 | Name resolution, scope analysis, symbol table |
 | `assura-types` | 33,800 | 1,081 | Type checking, 50+ domain-specific checkers |
 | `assura-smt` | 13,800 | 397 | Z3/CVC5 SMT solver integration, verification |
@@ -559,7 +559,7 @@ cargo fmt --all && cargo clippy --workspace -- -D warnings && cargo test --works
 | Library | Version | Used For |
 |---------|---------|----------|
 | logos | 0.16 | Lexer (derive macro) |
-| rowan | 0.16 | Lossless concrete syntax tree |
+| rowan | 0.17 | Lossless concrete syntax tree (immutable; no mutable edit APIs) |
 | ariadne | 0.6 | Error display |
 | z3 | 0.20 | SMT solver bindings (optional, behind `z3-verify` feature) |
 | prettyplease | 0.2 | Rust source formatting in codegen |