feat(lsp): textDocument/implementation for interfaces (0.13)

Go-to-implementation resolves interface types to implementing types and
interface methods to extend Type for Iface method decls (Circle+Square).

tools/smoke_lsp_implementation.sh

@@ -0,0 +1,112 @@
+#!/usr/bin/env bash
+# Smoke: textDocument/implementation (bux-lsp 0.13)
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+LSP="$ROOT/tools/bux-lsp"
+TMP=$(mktemp -d)
+trap 'rm -rf "$TMP"' EXIT
+
+if [[ ! -x "$LSP" ]]; then
+  (cd "$ROOT" && make lsp >/dev/null)
+fi
+
+cat > "$TMP/Main.bux" <<'EOF'
+interface Drawable {
+    func Draw(self: &Self);
+}
+struct Circle {
+    radius: int;
+}
+struct Square {
+    side: int;
+}
+extend Circle for Drawable {
+    func Draw(self: &Circle) {
+        let r: int = self.radius;
+    }
+}
+extend Square for Drawable {
+    func Draw(self: &Square) {
+        let s: int = self.side;
+    }
+}
+func Render(c: Circle) {
+    c.Draw();
+}
+func Main() -> int {
+    return 0;
+}
+EOF
+
+rpc() {
+  local body="$1"
+  local len
+  len=$(printf '%s' "$body" | wc -c)
+  printf 'Content-Length: %s\r\n\r\n%s' "$len" "$body"
+}
+
+CONTENT_JSON=$(python3 -c 'import json,sys; print(json.dumps(open(sys.argv[1]).read()))' "$TMP/Main.bux")
+URI="file://$TMP/Main.bux"
+
+# Drawable interface name ~ line 0 character 10
+# Draw iface method ~ line 1 character 9
+# c.Draw() call ~ line 22 character 6 (approx)
+{
+  rpc '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"capabilities":{},"rootUri":"file://'"$TMP"'"}}'
+  rpc '{"jsonrpc":"2.0","method":"initialized","params":{}}'
+  rpc '{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"'"$URI"'","languageId":"bux","version":1,"text":'"$CONTENT_JSON"'}}}'
+  # implementation on interface type Drawable
+  rpc '{"jsonrpc":"2.0","id":2,"method":"textDocument/implementation","params":{"textDocument":{"uri":"'"$URI"'"},"position":{"line":0,"character":10}}}'
+  # implementation on iface method Draw
+  rpc '{"jsonrpc":"2.0","id":3,"method":"textDocument/implementation","params":{"textDocument":{"uri":"'"$URI"'"},"position":{"line":1,"character":9}}}'
+  rpc '{"jsonrpc":"2.0","id":4,"method":"shutdown","params":null}'
+  rpc '{"jsonrpc":"2.0","method":"exit","params":null}'
+} | "$LSP" 2>/dev/null | tr '\r' '\n' > "$TMP/out.txt"
+
+if ! grep -q '0.13.0' "$TMP/out.txt"; then
+  echo "WARN: version not 0.13.0"
+fi
+
+if ! grep -q 'implementationProvider' "$TMP/out.txt"; then
+  echo "FAIL: missing implementationProvider capability"
+  cat "$TMP/out.txt"
+  exit 1
+fi
+
+# id 2: interface → Circle + Square type locations
+# Count locations in response for id 2 roughly via line ranges mentioning Circle/Square
+# Parse with python for robustness
+python3 - <<'PY' "$TMP/out.txt"
+import json, sys, re
+raw = open(sys.argv[1]).read()
+# Split Content-Length messages into JSON bodies
+bodies = []
+for m in re.finditer(r'Content-Length:\s*(\d+)\s*\n\s*\n', raw):
+    pass
+# Simpler: find all JSON objects with "id"
+parts = re.split(r'Content-Length:\s*\d+\s*', raw)
+for p in parts:
+    p = p.strip()
+    if not p.startswith('{'):
+        continue
+    try:
+        j = json.loads(p)
+    except Exception:
+        continue
+    if j.get('id') == 2:
+        r = j.get('result') or []
+        if len(r) < 2:
+            print(f"FAIL: interface Drawable expected ≥2 implementor types, got {len(r)}")
+            print(json.dumps(j, indent=2)[:800])
+            sys.exit(1)
+        print(f"  interface Drawable → {len(r)} type location(s)")
+    if j.get('id') == 3:
+        r = j.get('result') or []
+        if len(r) < 2:
+            print(f"FAIL: iface method Draw expected ≥2 implementors, got {len(r)}")
+            print(json.dumps(j, indent=2)[:800])
+            sys.exit(1)
+        # Expect two method sites (Circle.Draw + Square.Draw)
+        print(f"  iface Draw → {len(r)} method location(s)")
+print("PASS: LSP textDocument/implementation (0.13)")
+PY