fix(rust-lsp): keep proc-macro expansion on in Reduced Memory mode (#2598)

CHANGELOG.md

@@ -23,6 +23,7 @@ For live updates on Fresh, [follow me on X](https://x.com/TheNoamLewis).
 ### Bug Fixes
 
 * **LSP diagnostic fixes**: the gutter marker, `F8` target, hover, and panel now shift with inserted/deleted lines instead of freezing at the pre-edit position until the next save (#2602); and dismissing a hover popup no longer drops an unrelated error from the status bar, gutter, and `F8` navigation (#2601).
+* **Rust LSP Reduced Memory mode**: hover and Go to Definition no longer silently fail on macro names and inside macro arguments (e.g. a call inside `println!(...)`/`format!(...)`); the mode was disabling proc-macro expansion, which rust-analyzer also uses to resolve identifiers inside macro invocations. Proc-macro expansion now stays on in Reduced mode (#2598).
 * **LSP Rename keeps focus** - a cross-file F2 rename no longer jumps you to the definition's file at a stale cursor position (#2599).
 * **LSP now pulls diagnostics from every server** configured for a language, not just the first - e.g. both `ruff` and `ty` for Python now stay live (#2615, reported by @ak24watch).
 * **Format Buffer respects the selection** - with an active selection and a server that supports range formatting, only the selected range is formatted instead of silently reformatting the whole file (#2605).

crates/fresh-editor/config.example.json

@@ -578,7 +578,7 @@
           "enable": false
         },
         "procMacro": {
-          "enable": false
+          "enable": true
         },
         "cargo": {
           "buildScripts": {

crates/fresh-editor/plugins/rust-lsp.ts

@@ -182,13 +182,23 @@ editor.on("action_popup_result", (data) => {
 // Reduced-memory init options for rust-analyzer:
 // - checkOnSave: false - disables cargo check on every save (#1 cause of slowdowns)
 // - cachePriming.enable: false - no background indexing of entire crate graph
-// - procMacro.enable: false - no proc-macro expansion (saves CPU/RAM)
 // - cargo.buildScripts.enable: false - no build.rs
 // - cargo.autoreload: false - manual reload only
+//
+// procMacro stays ENABLED on purpose. rust-analyzer resolves identifiers
+// *inside* a macro invocation's arguments (and the macro name itself)
+// through macro expansion, so turning procMacro off silently kills hover
+// and Go to Definition for the macro name and everything inside its args —
+// including built-in macros like println!/format!/assert!, which are among
+// the most common cursor positions in real Rust code. Losing navigation
+// there makes the editor look randomly broken, which is not the intent of a
+// memory mode. Proc-macro expansion is comparatively cheap next to
+// checkOnSave/cachePriming, and the process limits below still cap RAM/CPU.
+// See issue #2598.
 const REDUCED_MEMORY_INIT_OPTIONS = {
   checkOnSave: false,
   cachePriming: { enable: false },
-  procMacro: { enable: false },
+  procMacro: { enable: true },
   cargo: {
     buildScripts: { enable: false },
     autoreload: false,
@@ -258,7 +268,7 @@ editor.on("action_popup_result", (data) => {
         processLimits: REDUCED_MEMORY_PROCESS_LIMITS,
       });
       editor.restartLspForLanguage("rust");
-      editor.setStatus("Rust LSP: Reduced Memory mode — checkOnSave, procMacro, cachePriming disabled");
+      editor.setStatus("Rust LSP: Reduced Memory mode — checkOnSave, cachePriming, buildScripts disabled (macro navigation kept)");
       break;
 
     case "dismiss":

docs/features/lsp.md

@@ -209,7 +209,9 @@ Some LSP servers expect a different `languageId` than Fresh's internal language
 
 ### Rust LSP Mode Switching
 
-Use "Switch Rust Analyzer Mode" from the command palette to toggle between Full and Reduced Memory modes for rust-analyzer.
+Use **Rust LSP: Configure Mode** from the command palette to toggle between Full and Reduced Memory modes for rust-analyzer.
+
+**Reduced Memory** mode restarts rust-analyzer with `checkOnSave`, `cachePriming`, and `cargo.buildScripts` disabled, plus 50% RAM / 90% CPU process limits. Proc-macro expansion stays enabled so hover and Go to Definition keep working on macro names and on symbols inside macro arguments (e.g. a call inside `println!(...)`); disabling it silently breaks that navigation. **Full** mode restores rust-analyzer's defaults with no process limits.
 
 ## Configuring Language Detection via Settings UI