diff --git a/crates/sml-statics-types/src/display.rs b/crates/sml-statics-types/src/display.rs
index 3b42c8c7b..cf53aa902 100644
--- a/crates/sml-statics-types/src/display.rs
+++ b/crates/sml-statics-types/src/display.rs
@@ -366,19 +366,14 @@ impl fmt::Display for RecordMetaVarDisplay<'_> {
 impl Incompatible {
   /// Returns a value that displays this.
   #[must_use]
-  pub fn display<'a>(
-    &'a self,
-    st: &'a St,
-    lines: config::DiagnosticLines,
-  ) -> impl fmt::Display + 'a {
-    IncompatibleDisplay { flavor: self, st, lines }
+  pub fn display<'a>(&'a self, st: &'a St) -> impl fmt::Display + 'a {
+    IncompatibleDisplay { flavor: self, st }
   }
 }
 
 struct IncompatibleDisplay<'a> {
   flavor: &'a Incompatible,
   st: &'a St,
-  lines: config::DiagnosticLines,
 }
 
 impl fmt::Display for IncompatibleDisplay<'_> {
@@ -400,8 +395,8 @@ impl fmt::Display for IncompatibleDisplay<'_> {
         write!(f, "`{a}` and `{b}` are different type constructors")
       }
       Incompatible::HeadMismatch(a, b) => {
-        let a_display = a.display(self.st, self.lines);
-        let b_display = b.display(self.st, self.lines);
+        let a_display = a.display(self.st, config::DiagnosticLines::One);
+        let b_display = b.display(self.st, config::DiagnosticLines::One);
         let a_desc = a.desc();
         let b_desc = b.desc();
         write!(f, "`{a_display}` is {a_desc}, but `{b_display}` is {b_desc}")
@@ -417,7 +412,7 @@ impl fmt::Display for IncompatibleDisplay<'_> {
         write!(f, "record types are not compatible with the `{ov}` overload")
       }
       Incompatible::OverloadHeadMismatch(ov, ty) => {
-        let ty_display = ty.display(self.st, self.lines);
+        let ty_display = ty.display(self.st, config::DiagnosticLines::One);
         let ty_desc = ty.desc();
         write!(f, "`{ov}` is an overloaded type, but `{ty_display}` is {ty_desc}")
       }
@@ -425,13 +420,13 @@ impl fmt::Display for IncompatibleDisplay<'_> {
         write!(f, "unresolved record type is missing field: `{lab}`")
       }
       Incompatible::UnresolvedRecordHeadMismatch(rows, ty) => {
-        let ty_display = ty.display(self.st, self.lines);
+        let ty_display = ty.display(self.st, config::DiagnosticLines::One);
         let ty_desc = ty.desc();
-        let rows = record_meta_var(self.st, rows, self.lines);
+        let rows = record_meta_var(self.st, rows, config::DiagnosticLines::One);
         write!(f, "`{rows}` is an unresolved record type, but `{ty_display}` is {ty_desc}")
       }
       Incompatible::NotEqTy(ty, not_eq) => {
-        let ty = ty.display(self.st, self.lines);
+        let ty = ty.display(self.st, config::DiagnosticLines::One);
         write!(f, "not an equality type because it contains {not_eq}: `{ty}`")
       }
     }
diff --git a/crates/sml-statics/src/error.rs b/crates/sml-statics/src/error.rs
index 9676abc73..b527982a2 100644
--- a/crates/sml-statics/src/error.rs
+++ b/crates/sml-statics/src/error.rs
@@ -81,15 +81,15 @@ impl fmt::Display for ErrorKindDisplay<'_> {
       ErrorKind::Missing(item, name) => write!(f, "missing {item} required by signature: `{name}`"),
       ErrorKind::Extra(item, name) => write!(f, "extra {item} not present in signature: `{name}`"),
       ErrorKind::Circularity(circ) => {
-        let mv = circ.meta_var.display(self.st, self.lines);
-        let ty = circ.ty.display(self.st, self.lines);
+        let mv = circ.meta_var.display(self.st, config::DiagnosticLines::One);
+        let ty = circ.ty.display(self.st, config::DiagnosticLines::One);
         write!(f, "circular type: `{mv}` occurs in `{ty}`")
       }
       ErrorKind::IncompatibleTys(reason, want, got) => {
-        let reason = reason.display(self.st, self.lines);
+        let reason = reason.display(self.st);
         write!(f, "incompatible types: {reason}")?;
-        let want = want.display(self.st, self.lines);
-        let got = got.display(self.st, self.lines);
+        let want = want.display(self.st, config::DiagnosticLines::One);
+        let got = got.display(self.st, config::DiagnosticLines::One);
         match self.lines {
           config::DiagnosticLines::One => {
             write!(f, ": expected `{want}`, found `{got}`")
@@ -112,7 +112,7 @@ impl fmt::Display for ErrorKindDisplay<'_> {
       ErrorKind::ConPatMustHaveArg => f.write_str("missing argument for constructor pattern"),
       ErrorKind::InvalidAsPatName(name) => write!(f, "invalid `as` pat name: `{name}`"),
       ErrorKind::TyEscape(ty) => {
-        let ty = ty.display(self.st, self.lines);
+        let ty = ty.display(self.st, config::DiagnosticLines::One);
         write!(f, "type escapes its scope: `{ty}`")
       }
       ErrorKind::ValRecExpNotFn => f.write_str("the expression for a `val rec` was not a `fn`"),
@@ -124,7 +124,7 @@ impl fmt::Display for ErrorKindDisplay<'_> {
       ErrorKind::InvalidRebindName(name) => write!(f, "cannot re-bind name: `{name}`"),
       ErrorKind::WrongIdStatus(name) => write!(f, "incompatible identifier statuses: `{name}`"),
       ErrorKind::UnresolvedRecordTy(rows) => {
-        let ty = record_meta_var(self.st, rows, self.lines);
+        let ty = record_meta_var(self.st, rows, config::DiagnosticLines::One);
         write!(f, "cannot resolve `...` in record type: `{ty}`")
       }
       ErrorKind::OrPatNotSameBindings(name) => {
@@ -132,7 +132,7 @@ impl fmt::Display for ErrorKindDisplay<'_> {
       }
       ErrorKind::DecNotAllowedHere => f.write_str("`signature` or `functor` not allowed here"),
       ErrorKind::ExpHole(ty) => {
-        let ty = ty.display(self.st, self.lines);
+        let ty = ty.display(self.st, config::DiagnosticLines::One);
         write!(f, "expression hole with type `{ty}`")
       }
       ErrorKind::TyHole => f.write_str("type hole"),
@@ -146,11 +146,11 @@ impl fmt::Display for ErrorKindDisplay<'_> {
         f.write_str("type variable bound at `val` or `fun` not allowed here")
       }
       ErrorKind::CannotShareTy(path, ts) => {
-        let ts = ts.display(self.st, self.lines);
+        let ts = ts.display(self.st, config::DiagnosticLines::One);
         write!(f, "cannot share type `{path}` as `{ts}`")
       }
       ErrorKind::CannotRealizeTy(path, ts) => {
-        let ts = ts.display(self.st, self.lines);
+        let ts = ts.display(self.st, config::DiagnosticLines::One);
         write!(f, "cannot realize type `{path}` as `{ts}`")
       }
       ErrorKind::InvalidEq(name) => write!(f, "calling `=` or `<>` on `{name}`"),
@@ -176,7 +176,7 @@ impl fmt::Display for ErrorKindDisplay<'_> {
         write!(f, "`fn {name} => f {name}`, can be simplified to `f`")
       }
       ErrorKind::ShadowInCaseWithSameTy(name, ty_scheme) => {
-        let ty_scheme = ty_scheme.display(self.st, self.lines);
+        let ty_scheme = ty_scheme.display(self.st, config::DiagnosticLines::One);
         write!(f, "this pattern, which binds `{name}` with type `{ty_scheme}`, ")?;
         write!(f, "does not check any part of the matched expression for equality with the ")?;
         write!(f, "existing `{name}`, which has the same type, and which was already in scope")
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 9a3a60d15..cf0ab7b0c 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -13,6 +13,10 @@ The versioning system is basically the following:
   - If there's a really "big" change.
 - As mentioned, the "major" version is 0.
 
+## main
+
+- Use multi-line types less often in error messages.
+
 ## v0.14.0
 
 - Warn when a `.sig` file doesn't contain 1 `signature`.