IME · the candidate box clamps to the last layout: asked before the next one, it found nothing and macOS put it in the screen's corner (#7)

src/forms/tests/stale.rs

@@ -1,4 +1,4 @@
-use gpui::{AppContext, Context, IntoElement, Render, TestAppContext, Window};
+use gpui::{AppContext, Context, EntityInputHandler, IntoElement, Render, TestAppContext, Window};
 
 use super::setup;
 use crate::forms::{TextInput, UnitInput};
@@ -45,3 +45,24 @@ fn a_unit_gone_from_its_list_keeps_the_field(cx: &mut TestAppContext) {
     cx.run_until_parked();
     assert!(cx.debug_bounds("number-root").is_some());
 }
+
+#[gpui::test]
+fn an_ime_finds_its_composition_before_the_next_layout(cx: &mut TestAppContext) {
+    let (fields, cx) = super::open(1, false, cx);
+    let field = fields[0].clone();
+    super::focus(&field, cx);
+    field.update(cx, |input, cx| input.set_text("abc", cx));
+    cx.run_until_parked();
+    let laid = field
+        .read_with(cx, |input, _| input.bounds_for(3))
+        .expect("laid out");
+    let asked = cx.update(|window, cx| {
+        field.update(cx, |input, cx| {
+            input.replace_and_mark_text_in_range(None, "n", None, window, cx);
+            let at = gpui::Bounds::new(laid.origin, gpui::size(gpui::px(200.), laid.size.height));
+            input.bounds_for_range(3..4, at, window, cx)
+        })
+    });
+    let asked = asked.expect("the candidate box has a place");
+    assert_eq!(asked.origin, laid.origin, "at the caret, on its line");
+}

src/forms/text/ime.rs

@@ -126,19 +126,13 @@ impl EntityInputHandler for TextInput {
     fn bounds_for_range(
         &mut self,
         range_utf16: Range<usize>,
-        bounds: Bounds<Pixels>,
+        _: Bounds<Pixels>,
         _: &mut Window,
         _: &mut Context<Self>,
     ) -> Option<Bounds<Pixels>> {
         let range = self.range_from_utf16(&range_utf16);
-        let line_height = self.layout.as_ref()?.line_height;
-        let start = self.position_for(self.display_offset(range.start))?;
-        let end = self.position_for(self.display_offset(range.end))?;
-        let origin = bounds.origin - self.scroll;
-        Some(Bounds::from_corners(
-            origin + start,
-            origin + gpui::point(end.x, end.y + line_height),
-        ))
+        let (start, end) = (self.bounds_for(range.start)?, self.bounds_for(range.end)?);
+        Some(Bounds::from_corners(start.origin, end.bottom_left()))
     }
 
     fn character_index_for_point(