diff --git a/Cargo.toml b/Cargo.toml
index 10f2fed..0905981 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,6 +17,14 @@ members = ["xtask"]
 # `cdylib` is the plugin binary; `lib` (rlib) lets `cargo test` link the unit tests.
 crate-type = ["cdylib", "lib"]
 
+# Future-incompatibility warnings are deferred hard errors: rustc is telling you
+# this code stops compiling on some later release. Denying the group turns that
+# into a build failure the day it appears, rather than 16 of them accumulating
+# unnoticed until a toolchain bump breaks the build on a day you did not choose.
+# Style and clippy lints are deliberately untouched - they stay warnings.
+[lints.rust]
+future_incompatible = { level = "deny", priority = -1 }
+
 [dependencies]
 # Pinned to the exact commit of the local ./nih-plug reference clone so the build
 # is reproducible and matches the examples we read from. Bump the `rev` together
diff --git a/src/editor/crossover.rs b/src/editor/crossover.rs
index f644c15..be9144a 100644
--- a/src/editor/crossover.rs
+++ b/src/editor/crossover.rs
@@ -131,7 +131,7 @@ fn handle(
     }
 
     let col = if resp.dragged() || resp.hovered() { palette::TEXT_HOVER } else { color };
-    p.line_segment([pos2(x, top), pos2(x, bottom)], Stroke::new(2.0, col));
+    p.line_segment([pos2(x, top), pos2(x, bottom)], Stroke::new(2.0_f32, col));
     p.text(pos2(x, bottom - 1.0), Align2::CENTER_BOTTOM, fmt_hz(hz), FontId::proportional(10.0), palette::TEXT_BRIGHT);
 }
 
diff --git a/src/editor/gain_curve.rs b/src/editor/gain_curve.rs
index b566c14..2194f5b 100644
--- a/src/editor/gain_curve.rs
+++ b/src/editor/gain_curve.rs
@@ -52,14 +52,14 @@ pub(super) fn draw(ui: &mut egui::Ui, params: &Bari206Params, selected: usize, m
     let g6 = palette::GRID_FAINT;
     let x6 = x_for(-6.0);
     let y6 = y_for(-6.0);
-    p.line_segment([pos2(x6, top), pos2(x6, bottom)], Stroke::new(1.0, g6));
-    p.line_segment([pos2(left, y6), pos2(right, y6)], Stroke::new(1.0, g6));
+    p.line_segment([pos2(x6, top), pos2(x6, bottom)], Stroke::new(1.0_f32, g6));
+    p.line_segment([pos2(left, y6), pos2(right, y6)], Stroke::new(1.0_f32, g6));
 
     // Unity reference (out = in), bottom-left to top-right.
-    p.line_segment([pos2(left, bottom), pos2(right, top)], Stroke::new(1.0, palette::GRID));
+    p.line_segment([pos2(left, bottom), pos2(right, top)], Stroke::new(1.0_f32, palette::GRID));
     // Threshold marker on the input axis — shifted left by pre-gain (the comp sees in + pre).
     let tx = x_for((threshold - pre).clamp(FLOOR_DB, 0.0));
-    p.line_segment([pos2(tx, top), pos2(tx, bottom)], Stroke::new(1.0, palette::THRESHOLD_LINE));
+    p.line_segment([pos2(tx, top), pos2(tx, bottom)], Stroke::new(1.0_f32, palette::THRESHOLD_LINE));
 
     // Full wet transfer: drive into the comp, then makeup. (Mix not folded in.)
     let n = 96;
@@ -93,7 +93,7 @@ pub(super) fn draw(ui: &mut egui::Ui, params: &Bari206Params, selected: usize, m
         ));
     }
 
-    p.add(egui::Shape::line(pts, Stroke::new(1.6, palette::CURVE)));
+    p.add(egui::Shape::line(pts, Stroke::new(1.6_f32, palette::CURVE)));
 
     // Operating-point dot, on the curve at the current input.
     let driven = ext_in + pre;
diff --git a/src/editor/palette.rs b/src/editor/palette.rs
index 6dafdac..d85c80b 100644
--- a/src/editor/palette.rs
+++ b/src/editor/palette.rs
@@ -243,23 +243,23 @@ pub fn apply_visuals(ctx: &nih_plug_egui::egui::Context) {
     let w = &mut v.widgets;
     w.noninteractive.bg_fill = SURFACE_RAISED;
     w.noninteractive.weak_bg_fill = SURFACE_RAISED;
-    w.noninteractive.bg_stroke = Stroke::new(1.0, GRID_FAINT);
-    w.noninteractive.fg_stroke = Stroke::new(1.0, TEXT);
+    w.noninteractive.bg_stroke = Stroke::new(1.0_f32, GRID_FAINT);
+    w.noninteractive.fg_stroke = Stroke::new(1.0_f32, TEXT);
 
     w.inactive.bg_fill = TRACK;
     w.inactive.weak_bg_fill = TRACK;
-    w.inactive.bg_stroke = Stroke::new(1.0, GRID);
-    w.inactive.fg_stroke = Stroke::new(1.0, TEXT_BRIGHT);
+    w.inactive.bg_stroke = Stroke::new(1.0_f32, GRID);
+    w.inactive.fg_stroke = Stroke::new(1.0_f32, TEXT_BRIGHT);
 
     w.hovered.bg_fill = accent.edge;
     w.hovered.weak_bg_fill = accent.strip;
-    w.hovered.bg_stroke = Stroke::new(1.0, accent.edge);
-    w.hovered.fg_stroke = Stroke::new(1.0, TEXT_HOVER);
+    w.hovered.bg_stroke = Stroke::new(1.0_f32, accent.edge);
+    w.hovered.fg_stroke = Stroke::new(1.0_f32, TEXT_HOVER);
 
     w.active.bg_fill = accent.handle;
     w.active.weak_bg_fill = accent.edge;
-    w.active.bg_stroke = Stroke::new(1.0, accent.handle);
-    w.active.fg_stroke = Stroke::new(1.0, TEXT_HOVER);
+    w.active.bg_stroke = Stroke::new(1.0_f32, accent.handle);
+    w.active.fg_stroke = Stroke::new(1.0_f32, TEXT_HOVER);
 
     ctx.set_visuals(v);
 }
diff --git a/src/editor/plot.rs b/src/editor/plot.rs
index 807d8ee..b9b9cd4 100644
--- a/src/editor/plot.rs
+++ b/src/editor/plot.rs
@@ -170,7 +170,7 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut PlotState) {
     // Gridlines (dB).
     for &g in &[0.0f32, -12.0, -24.0, -48.0] {
         let y = y_for_db(g);
-        p.line_segment([pos2(left, y), pos2(right, y)], Stroke::new(1.0, palette::GRID_FAINT));
+        p.line_segment([pos2(left, y), pos2(right, y)], Stroke::new(1.0_f32, palette::GRID_FAINT));
         p.text(
             pos2(left + 2.0, y),
             Align2::LEFT_BOTTOM,
@@ -204,7 +204,7 @@ pub(super) fn draw(ui: &mut egui::Ui, meters: &Meters, state: &mut PlotState) {
                     ));
                 }
             }
-            p.add(egui::Shape::line(pts, Stroke::new(1.5, color)));
+            p.add(egui::Shape::line(pts, Stroke::new(1.5_f32, color)));
         };
         draw_series(&state.history.in_db[c], &|db| db, COLOR_IN, true);
         draw_series(&state.history.out_db[c], &|db| db, COLOR_OUT, true);