Rename the optimistic statement to guess

compiler/src/ast.rs

@@ -110,7 +110,7 @@ pub enum PathSeg {
 pub struct Target {
     pub name: String,
     pub path: Vec<PathSeg>,
-    /// `use name := …` (RG-7, O-4). `None`: not written by this form (an `optimistic` target).
+    /// `use name := …` (RG-7, O-4). `None`: not written by this form (a `guess` target).
     pub ctx: Option<bool>,
 }
 impl Target {

compiler/src/check.rs

@@ -2262,9 +2262,9 @@ impl<'a> Checker<'a> {
         for f in run_findings(stmts, action, bound, inferred) {
             let n = &f.name;
             match f.code {
-                Code::HeldWrite => self.err("HELD_WRITE", "AC-1c", format!("{n} := … comes before an `await` in a body that is an action because it writes and awaits (AC-1b), so it is held until the body ends (AC-1): for state that shows while the work runs, `optimistic {n} := …` (a source with a question, ST-5c); for a reset that lands now, `onFlush(() => {{ {n} := … }})` (EF-8); to hold it on purpose, declare the action (`action name() {{ … }}`); or write it after the `await`")),
+                Code::HeldWrite => self.err("HELD_WRITE", "AC-1c", format!("{n} := … comes before an `await` in a body that is an action because it writes and awaits (AC-1b), so it is held until the body ends (AC-1): for state that shows while the work runs, `guess {n} := …` (a source with a question, ST-5c); for a reset that lands now, `onFlush(() => {{ {n} := … }})` (EF-8); to hold it on purpose, declare the action (`action name() {{ … }}`); or write it after the `await`")),
                 Code::StaleOwnRead => self.err("STALE_OWN_READ", "AC-1d", format!("{n} is read after this change wrote it: the read sees the committed value, not the write (W-4) — keep the value you wrote in a local (`let v = …; {n} := v`) and read that, or write functionally (`{n} := v => …`, W-6)")),
-                Code::StaleWriteBack => self.err("STALE_WRITE_BACK", "AC-1e", format!("{n} := … after an `await` is computed from {n} as it was read before that `await`: whatever changed {n} in between (another action, a reload) is overwritten — write functionally (`{n} := v => …`, W-6), which applies to {n} as it stands at the write, or guess it (`optimistic`, AC-3) and let the answer replace the guess")),
+                Code::StaleWriteBack => self.err("STALE_WRITE_BACK", "AC-1e", format!("{n} := … after an `await` is computed from {n} as it was read before that `await`: whatever changed {n} in between (another action, a reload) is overwritten — write functionally (`{n} := v => …`, W-6), which applies to {n} as it stands at the write, or guess it (`guess`, AC-3) and let the answer replace the guess")),
             }
         }
     }
@@ -2351,12 +2351,12 @@ impl<'a> Checker<'a> {
                     }
                     if op == "optimistic" {
                         if !ctx.in_action {
-                            self.err("OPTIMISTIC_OUTSIDE_HOLD", "AC-3", "optimistic outside an action: a guess needs a hold to live in — an apply block is never an action (its return is the cleanup, EF-5): declare one, `action save(v) { optimistic … }`, and call it from the block".into());
+                            self.err("GUESS_OUTSIDE_HOLD", "AC-3", "a guess outside an action: it needs a hold to live in — an apply block is never an action (its return is the cleanup, EF-5): declare one, `action save(v) { guess … }`, and call it from the block".into());
                         }
                         if let Some(t) = tsym {
                             if self.syms[t].kind == SymKind::Source && !self.syms[t].question {
                                 self.err(
-                                    "OPTIMISTIC_NO_QUESTION",
+                                    "GUESS_NO_QUESTION",
                                     "AC-3",
                                     format!("{} is declared with := — a guess needs a question to confirm it (source {} = …, ST-5c)", target.name, target.name),
                                 );

compiler/src/infer.rs

@@ -18,7 +18,7 @@ pub enum Trigger {
 pub fn trigger_text(t: Trigger) -> &'static str {
     match t {
         Trigger::WriteAwait => "it writes and awaits",
-        Trigger::Optimistic => "it has `optimistic`",
+        Trigger::Optimistic => "it has `guess`",
         Trigger::Affects => "it has `affects`",
     }
 }

compiler/src/parse.rs

@@ -42,7 +42,7 @@ re!(LINE_COMMENT, r"//.*$");
 
 static KEYWORDS: LazyLock<HashSet<&'static str>> = LazyLock::new(|| {
     [
-        "source", "effect", "component", "ref", "await", "latest", "loading", "errored", "fallback", "on", "deferred", "action", "optimistic", "refresh", "affects", "if", "else", "pre", "peek", "fn", "let", "for", "in", "true", "false", "undefined",
+        "source", "effect", "component", "ref", "await", "latest", "loading", "errored", "fallback", "on", "deferred", "action", "guess", "refresh", "affects", "if", "else", "pre", "peek", "fn", "let", "for", "in", "true", "false", "undefined",
         "null", "provide", "context", "use", "import", "export", "from", "pure", "return", "type", "interface", "try", "catch", "finally", "throw", "portal",
     ]
     .into_iter()
@@ -925,7 +925,7 @@ fn parse_path(c: &mut Cursor) -> R<Vec<PathSeg>> {
 fn parse_stmt(c: &mut Cursor) -> R<Stmt> {
     c.ws(true);
     let start = c.i;
-    if c.keyword("optimistic") {
+    if c.keyword("guess") {
         c.ws(true);
         let name = c.ident_or("target")?;
         let path = parse_path(c)?;

eval/README.md

@@ -86,7 +86,7 @@ predicted every frame right; the briefs here are stricter.
 - `tracker`: `assignToMe` cleared its error with a plain write (`assignError := ""`) inside an action that awaits,
   and a plain write in an async action is held until the action ends (AC-1), so the old error stayed up until the
   server answered. The fix is the `settings` app's own idiom: `assignError` a question source,
-  `optimistic assignError := ""`.
+  `guess assignError := ""` (since 2026-11-11 the references clear errors with `onFlush`, EF-8).
 
 ## Layout
 

eval/reference/chain1/rx/comments.rx

@@ -8,16 +8,16 @@ export component Comments(props: { id: number; user: string }) {
   source comments = await fetchComments(props.id)
   source sending: { id: number; author: string; text: string }[] = []
   shownSending = sending.filter(s => s.id == props.id)
-  source postError: string | null = null
+  source postError: string | null := null
   source commentInput: string := ""
 
   // a post error belongs to the issue it was made on: selecting another clears it
   effect (props.id) { postError := null }
 
   action postComment(id: number, author: string, text: string) {
-    optimistic postError := null
+    onFlush(() => { postError := null })
     try {
-      optimistic sending := [...sending, { id: id, author: author, text: text }]
+      guess sending := [...sending, { id: id, author: author, text: text }]
       await addComment(id, author, text)
       refresh comments
     } catch (e) {

eval/reference/chain1/rx/issues.rx

@@ -16,15 +16,15 @@ export component IssuesPage() {
   source issues key id = await fetchIssues(filter)
   source detail = selected == null ? null : found(await fetchIssue(selected), selected)
   source titleInput: string := ""
-  source assignError: string = ""
-  source renameError: string = ""
-  source closeError: string = ""
+  source assignError: string := ""
+  source renameError: string := ""
+  source closeError: string := ""
 
   action assignTo(id: number, who: string) {
-    optimistic assignError := ""
+    onFlush(() => { assignError := "" })
     try {
       let i = issues.findIndex(t => t.id == id)
-      optimistic issues[i].assignee := who
+      guess issues[i].assignee := who
       await assign(id, who)
       refresh issues
     } catch (e) {
@@ -33,14 +33,14 @@ export component IssuesPage() {
   }
 
   action renameTo(id: number, title: string) {
-    optimistic renameError := ""
+    onFlush(() => { renameError := "" })
     try {
       let i = issues.findIndex(t => t.id == id)
       if (i >= 0) {
-        optimistic issues[i].title := title
+        guess issues[i].title := title
       }
       if (detail != null && detail.id == id) {
-        optimistic detail.title := title
+        guess detail.title := title
       }
       await renameIssue(id, title)
       refresh issues
@@ -51,9 +51,9 @@ export component IssuesPage() {
   }
 
   action closeOne(id: number) {
-    optimistic closeError := ""
+    onFlush(() => { closeError := "" })
     try {
-      optimistic issues := issues.filter(t => t.id != id)
+      guess issues := issues.filter(t => t.id != id)
       await closeIssue(id)
       refresh issues
     } catch (e) {

eval/reference/chain1/rx/labels.rx

@@ -12,16 +12,16 @@ export component Labels(props: { id: number }) {
     ...labels.filter(l => !removing.some(r => r.id == props.id && r.label == l)),
     ...adding.filter(a => a.id == props.id).map(a => a.label),
   ]
-  source labelError: string = ""
+  source labelError: string := ""
   source labelInput: string := ""
 
   // a label error belongs to the issue it was made on: selecting another clears it
   effect (props.id) { labelError := "" }
 
   action add(id: number, label: string) {
-    optimistic labelError := ""
+    onFlush(() => { labelError := "" })
     try {
-      optimistic adding := [...adding, { id: id, label: label }]
+      guess adding := [...adding, { id: id, label: label }]
       await addLabel(id, label)
       refresh labels
     } catch (e) {
@@ -30,9 +30,9 @@ export component Labels(props: { id: number }) {
   }
 
   action remove(id: number, label: string) {
-    optimistic labelError := ""
+    onFlush(() => { labelError := "" })
     try {
-      optimistic removing := [...removing, { id: id, label: label }]
+      guess removing := [...removing, { id: id, label: label }]
       await removeLabel(id, label)
       refresh labels
     } catch (e) {

eval/reference/chain1/rx/settings.rx

@@ -13,11 +13,11 @@ fn validName(name: string): string =>
 
 export component SettingsPage() {
   source settings: Settings = await loadSettings()
-  source saveError: string = ""
+  source saveError: string := ""
 
   action save(next: Settings) {
-    optimistic settings := next
-    optimistic saveError := ""
+    guess settings := next
+    onFlush(() => { saveError := "" })
     affects settings
     try {
       let saved = await saveSettings(next)

eval/reference/chain2/rx/comments.rx

@@ -8,16 +8,16 @@ export component Comments(props: { id: number; user: string }) {
   source comments = await fetchComments(props.id)
   source sending: { id: number; author: string; text: string }[] = []
   shownSending = sending.filter(s => s.id == props.id)
-  source postError: string | null = null
+  source postError: string | null := null
   source commentInput: string := ""
 
   // a post error belongs to the issue it was made on: selecting another clears it
   effect (props.id) { postError := null }
 
   action postComment(id: number, author: string, text: string) {
-    optimistic postError := null
+    onFlush(() => { postError := null })
     try {
-      optimistic sending := [...sending, { id: id, author: author, text: text }]
+      guess sending := [...sending, { id: id, author: author, text: text }]
       await addComment(id, author, text)
       refresh comments
     } catch (e) {

eval/reference/chain2/rx/issues.rx

@@ -24,16 +24,16 @@ export component IssuesPage(props: { onOpenCount: (n: number) => void }) {
   source issues key id = await fetchIssues(filter)
   source detail = selected == null ? null : found(await fetchIssue(selected), selected)
   source titleInput: string := ""
-  source assignError: string = ""
-  source renameError: string = ""
-  source closeError: string = ""
+  source assignError: string := ""
+  source renameError: string := ""
+  source closeError: string := ""
 
 
   action assignTo(id: number, who: string) {
-    optimistic assignError := ""
+    onFlush(() => { assignError := "" })
     try {
       let i = issues.findIndex(t => t.id == id)
-      optimistic issues[i].assignee := who
+      guess issues[i].assignee := who
       await assign(id, who)
       refresh issues
     } catch (e) {
@@ -42,14 +42,14 @@ export component IssuesPage(props: { onOpenCount: (n: number) => void }) {
   }
 
   action renameTo(id: number, title: string) {
-    optimistic renameError := ""
+    onFlush(() => { renameError := "" })
     try {
       let i = issues.findIndex(t => t.id == id)
       if (i >= 0) {
-        optimistic issues[i].title := title
+        guess issues[i].title := title
       }
       if (detail != null && detail.id == id) {
-        optimistic detail.title := title
+        guess detail.title := title
       }
       await renameIssue(id, title)
       refresh issues
@@ -60,9 +60,9 @@ export component IssuesPage(props: { onOpenCount: (n: number) => void }) {
   }
 
   action closeOne(id: number) {
-    optimistic closeError := ""
+    onFlush(() => { closeError := "" })
     try {
-      optimistic issues := issues.filter(t => t.id != id)
+      guess issues := issues.filter(t => t.id != id)
       await closeIssue(id)
       refresh issues
     } catch (e) {

eval/reference/chain2/rx/labels.rx

@@ -12,16 +12,16 @@ export component Labels(props: { id: number }) {
     ...labels.filter(l => !removing.some(r => r.id == props.id && r.label == l)),
     ...adding.filter(a => a.id == props.id).map(a => a.label),
   ]
-  source labelError: string = ""
+  source labelError: string := ""
   source labelInput: string := ""
 
   // a label error belongs to the issue it was made on: selecting another clears it
   effect (props.id) { labelError := "" }
 
   action add(id: number, label: string) {
-    optimistic labelError := ""
+    onFlush(() => { labelError := "" })
     try {
-      optimistic adding := [...adding, { id: id, label: label }]
+      guess adding := [...adding, { id: id, label: label }]
       await addLabel(id, label)
       refresh labels
     } catch (e) {
@@ -30,9 +30,9 @@ export component Labels(props: { id: number }) {
   }
 
   action remove(id: number, label: string) {
-    optimistic labelError := ""
+    onFlush(() => { labelError := "" })
     try {
-      optimistic removing := [...removing, { id: id, label: label }]
+      guess removing := [...removing, { id: id, label: label }]
       await removeLabel(id, label)
       refresh labels
     } catch (e) {

eval/reference/chain2/rx/settings.rx

@@ -13,11 +13,11 @@ fn validName(name: string): string =>
 
 export component SettingsPage() {
   source settings: Settings = await loadSettings()
-  source saveError: string = ""
+  source saveError: string := ""
 
   action save(next: Settings) {
-    optimistic settings := next
-    optimistic saveError := ""
+    guess settings := next
+    onFlush(() => { saveError := "" })
     affects settings
     try {
       let saved = await saveSettings(next)

eval/reference/chain3/rx/comments.rx

@@ -8,16 +8,16 @@ export component Comments(props: { id: number; user: string }) {
   source comments = await fetchComments(props.id)
   source sending: { id: number; author: string; text: string }[] = []
   shownSending = sending.filter(s => s.id == props.id)
-  source postError: string | null = null
+  source postError: string | null := null
   source commentInput: string := ""
 
   // a post error belongs to the issue it was made on: selecting another clears it
   effect (props.id) { postError := null }
 
   action postComment(id: number, author: string, text: string) {
-    optimistic postError := null
+    onFlush(() => { postError := null })
     try {
-      optimistic sending := [...sending, { id: id, author: author, text: text }]
+      guess sending := [...sending, { id: id, author: author, text: text }]
       await addComment(id, author, text)
       refresh comments
     } catch (e) {

eval/reference/chain3/rx/issues.rx

@@ -25,16 +25,16 @@ export component IssuesPage(props: { onOpenCount: (n: number) => void; onOpenHel
   source issues key id = await fetchIssues(filter)
   source detail = selected == null ? null : found(await fetchIssue(selected), selected)
   source titleInput: string := ""
-  source assignError: string = ""
-  source renameError: string = ""
-  source closeError: string = ""
+  source assignError: string := ""
+  source renameError: string := ""
+  source closeError: string := ""
 
 
   action assignTo(id: number, who: string) {
-    optimistic assignError := ""
+    onFlush(() => { assignError := "" })
     try {
       let i = issues.findIndex(t => t.id == id)
-      optimistic issues[i].assignee := who
+      guess issues[i].assignee := who
       await assign(id, who)
       refresh issues
     } catch (e) {
@@ -43,14 +43,14 @@ export component IssuesPage(props: { onOpenCount: (n: number) => void; onOpenHel
   }
 
   action renameTo(id: number, title: string) {
-    optimistic renameError := ""
+    onFlush(() => { renameError := "" })
     try {
       let i = issues.findIndex(t => t.id == id)
       if (i >= 0) {
-        optimistic issues[i].title := title
+        guess issues[i].title := title
       }
       if (detail != null && detail.id == id) {
-        optimistic detail.title := title
+        guess detail.title := title
       }
       await renameIssue(id, title)
       refresh issues
@@ -61,9 +61,9 @@ export component IssuesPage(props: { onOpenCount: (n: number) => void; onOpenHel
   }
 
   action closeOne(id: number) {
-    optimistic closeError := ""
+    onFlush(() => { closeError := "" })
     try {
-      optimistic issues := issues.filter(t => t.id != id)
+      guess issues := issues.filter(t => t.id != id)
       await closeIssue(id)
       refresh issues
     } catch (e) {