diff --git a/crates/typst-syntax/src/node.rs b/crates/typst-syntax/src/node.rs
index dd5deab2a..9b73dd7f0 100644
--- a/crates/typst-syntax/src/node.rs
+++ b/crates/typst-syntax/src/node.rs
@@ -3,7 +3,7 @@ use std::ops::{Deref, Range};
 use std::rc::Rc;
 use std::sync::Arc;
 
-use ecow::EcoString;
+use ecow::{eco_vec, EcoString, EcoVec};
 
 use super::ast::AstNode;
 use super::{FileId, Span, SyntaxKind};
@@ -616,7 +616,7 @@ impl ErrorNode {
             error: SyntaxError {
                 span: Span::detached(),
                 message: message.into(),
-                hints: vec![],
+                hints: eco_vec![],
             },
         }
     }
@@ -652,7 +652,7 @@ pub struct SyntaxError {
     pub message: EcoString,
     /// Additonal hints to the user, indicating how this error could be avoided
     /// or worked around.
-    pub hints: Vec<EcoString>,
+    pub hints: EcoVec<EcoString>,
 }
 
 impl SyntaxError {
diff --git a/crates/typst/src/diag.rs b/crates/typst/src/diag.rs
index 846ab78f1..9342606ec 100644
--- a/crates/typst/src/diag.rs
+++ b/crates/typst/src/diag.rs
@@ -7,6 +7,7 @@ use std::str::Utf8Error;
 use std::string::FromUtf8Error;
 
 use comemo::Tracked;
+use ecow::{eco_vec, EcoVec};
 
 use crate::syntax::{PackageSpec, Span, Spanned, SyntaxError};
 use crate::{World, WorldExt};
@@ -29,14 +30,14 @@ macro_rules! __bail {
     };
 
     ($error:expr) => {
-        return Err(Box::new(vec![$error]))
+        return Err(::ecow::eco_vec![$error])
     };
 
     ($span:expr, $fmt:literal $(, $arg:expr)* $(,)?) => {
-        return Err(Box::new(vec![$crate::diag::SourceDiagnostic::error(
+        return Err(::ecow::eco_vec![$crate::diag::SourceDiagnostic::error(
             $span,
             $crate::diag::eco_format!($fmt, $($arg),*),
-        )]))
+        )])
     };
 }
 
@@ -75,7 +76,7 @@ macro_rules! __warning {
 }
 
 /// A result that can carry multiple source errors.
-pub type SourceResult<T> = Result<T, Box<Vec<SourceDiagnostic>>>;
+pub type SourceResult<T> = Result<T, EcoVec<SourceDiagnostic>>;
 
 /// An error or warning in a source file.
 ///
@@ -90,10 +91,10 @@ pub struct SourceDiagnostic {
     /// A diagnostic message describing the problem.
     pub message: EcoString,
     /// The trace of function calls leading to the problem.
-    pub trace: Vec<Spanned<Tracepoint>>,
+    pub trace: EcoVec<Spanned<Tracepoint>>,
     /// Additonal hints to the user, indicating how this problem could be avoided
     /// or worked around.
-    pub hints: Vec<EcoString>,
+    pub hints: EcoVec<EcoString>,
 }
 
 /// The severity of a [`SourceDiagnostic`].
@@ -111,9 +112,9 @@ impl SourceDiagnostic {
         Self {
             severity: Severity::Error,
             span,
-            trace: vec![],
+            trace: eco_vec![],
             message: message.into(),
-            hints: vec![],
+            hints: eco_vec![],
         }
     }
 
@@ -122,9 +123,9 @@ impl SourceDiagnostic {
         Self {
             severity: Severity::Warning,
             span,
-            trace: vec![],
+            trace: eco_vec![],
             message: message.into(),
-            hints: vec![],
+            hints: eco_vec![],
         }
     }
 
@@ -152,7 +153,7 @@ impl From<SyntaxError> for SourceDiagnostic {
             severity: Severity::Error,
             span: error.span,
             message: error.message,
-            trace: vec![],
+            trace: eco_vec![],
             hints: error.hints,
         }
     }
@@ -203,7 +204,7 @@ impl<T> Trace<T> for SourceResult<T> {
     {
         self.map_err(|mut errors| {
             let Some(trace_range) = world.range(span) else { return errors };
-            for error in errors.iter_mut() {
+            for error in errors.make_mut().iter_mut() {
                 // Skip traces that surround the error.
                 if let Some(error_range) = world.range(error.span) {
                     if error.span.id() == span.id()
@@ -242,7 +243,7 @@ where
                 diagnostic
                     .hint("you can adjust the project root with the --root argument");
             }
-            Box::new(vec![diagnostic])
+            eco_vec![diagnostic]
         })
     }
 }
@@ -263,9 +264,7 @@ pub struct HintedString {
 impl<T> At<T> for Result<T, HintedString> {
     fn at(self, span: Span) -> SourceResult<T> {
         self.map_err(|diags| {
-            Box::new(vec![
-                SourceDiagnostic::error(span, diags.message).with_hints(diags.hints)
-            ])
+            eco_vec![SourceDiagnostic::error(span, diags.message).with_hints(diags.hints)]
         })
     }
 }
diff --git a/crates/typst/src/eval/args.rs b/crates/typst/src/eval/args.rs
index aad9fda6a..c347f5277 100644
--- a/crates/typst/src/eval/args.rs
+++ b/crates/typst/src/eval/args.rs
@@ -1,6 +1,6 @@
 use std::fmt::{self, Debug, Formatter};
 
-use ecow::{eco_format, EcoString, EcoVec};
+use ecow::{eco_format, eco_vec, EcoString, EcoVec};
 
 use super::{func, scope, ty, Array, Dict, FromValue, IntoValue, Repr, Str, Value};
 use crate::diag::{bail, At, SourceDiagnostic, SourceResult};
@@ -155,7 +155,7 @@ impl Args {
         T: FromValue<Spanned<Value>>,
     {
         let mut list = vec![];
-        let mut errors = vec![];
+        let mut errors = eco_vec![];
         self.items.retain(|item| {
             if item.name.is_some() {
                 return true;
@@ -169,7 +169,7 @@ impl Args {
             false
         });
         if !errors.is_empty() {
-            return Err(Box::new(errors));
+            return Err(errors);
         }
         Ok(list)
     }
diff --git a/crates/typst/src/eval/mod.rs b/crates/typst/src/eval/mod.rs
index b6dbace9f..b527bed1e 100644
--- a/crates/typst/src/eval/mod.rs
+++ b/crates/typst/src/eval/mod.rs
@@ -134,7 +134,7 @@ pub fn eval(
     let root = source.root();
     let errors = root.errors();
     if !errors.is_empty() && vm.inspected.is_none() {
-        return Err(Box::new(errors.into_iter().map(Into::into).collect()));
+        return Err(errors.into_iter().map(Into::into).collect());
     }
 
     // Evaluate the module.
@@ -178,7 +178,7 @@ pub fn eval_string(
 
     let errors = root.errors();
     if !errors.is_empty() {
-        return Err(Box::new(errors.into_iter().map(Into::into).collect()));
+        return Err(errors.into_iter().map(Into::into).collect());
     }
 
     // Prepare VT.
@@ -1786,7 +1786,7 @@ impl Eval for ast::ModuleImport<'_> {
                 }
             }
             Some(ast::Imports::Items(items)) => {
-                let mut errors = vec![];
+                let mut errors = eco_vec![];
                 for item in items.iter() {
                     let original_ident = item.original_name();
                     if let Some(value) = scope.get(&original_ident) {
@@ -1808,7 +1808,7 @@ impl Eval for ast::ModuleImport<'_> {
                     }
                 }
                 if !errors.is_empty() {
-                    return Err(Box::new(errors));
+                    return Err(errors);
                 }
             }
         }
diff --git a/crates/typst/src/model/mod.rs b/crates/typst/src/model/mod.rs
index 2741f7316..dcad87419 100644
--- a/crates/typst/src/model/mod.rs
+++ b/crates/typst/src/model/mod.rs
@@ -8,6 +8,7 @@ mod realize;
 mod selector;
 mod styles;
 
+use ecow::EcoVec;
 #[doc(inline)]
 pub use typst_macros::elem;
 
@@ -89,7 +90,7 @@ pub fn typeset(
 
     // Promote delayed errors.
     if !delayed.0.is_empty() {
-        return Err(Box::new(delayed.0));
+        return Err(delayed.0);
     }
 
     Ok(document)
@@ -123,7 +124,7 @@ impl Vt<'_> {
         match f(self) {
             Ok(value) => value,
             Err(errors) => {
-                for error in *errors {
+                for error in errors {
                     self.delayed.push(error);
                 }
                 T::default()
@@ -134,7 +135,7 @@ impl Vt<'_> {
 
 /// Holds delayed errors.
 #[derive(Default, Clone)]
-pub struct DelayedErrors(Vec<SourceDiagnostic>);
+pub struct DelayedErrors(EcoVec<SourceDiagnostic>);
 
 impl DelayedErrors {
     /// Create an empty list of delayed errors.
diff --git a/tests/src/tests.rs b/tests/src/tests.rs
index 41fd00e86..bdbfd3979 100644
--- a/tests/src/tests.rs
+++ b/tests/src/tests.rs
@@ -545,7 +545,7 @@ fn test_part(
         Ok(document) => (document.pages, tracer.warnings()),
         Err(errors) => {
             let mut warnings = tracer.warnings();
-            warnings.extend(*errors);
+            warnings.extend(errors);
             (vec![], warnings)
         }
     };