4 files changed, 14 insertions, 7 deletions
diff --git a/crates/typst/src/eval/access.rs b/crates/typst/src/eval/access.rs
index 99b2f72e..e3bf2bf0 100644
--- a/crates/typst/src/eval/access.rs
+++ b/crates/typst/src/eval/access.rs
@@ -7,7 +7,7 @@ use crate::syntax::ast::{self, AstNode};
 
 /// Access an expression mutably.
 pub(crate) trait Access {
-    /// Access the value.
+    /// Access the expression's evaluated value mutably.
     fn access<'a>(self, vm: &'a mut Vm) -> SourceResult<&'a mut Value>;
 }
 
diff --git a/crates/typst/src/foundations/array.rs b/crates/typst/src/foundations/array.rs
index 6f7c6347..27f56194 100644
--- a/crates/typst/src/foundations/array.rs
+++ b/crates/typst/src/foundations/array.rs
@@ -113,7 +113,7 @@ impl Array {
         let len = self.len();
         self.locate_opt(index, false)
             .and_then(move |i| self.0.make_mut().get_mut(i))
-            .ok_or_else(|| out_of_bounds_no_default(index, len))
+            .ok_or_else(|| out_of_bounds(index, len))
     }
 
     /// Resolve an index or throw an out of bounds error.
diff --git a/crates/typst/src/foundations/cast.rs b/crates/typst/src/foundations/cast.rs
index 6a40cecc..716eae9d 100644
--- a/crates/typst/src/foundations/cast.rs
+++ b/crates/typst/src/foundations/cast.rs
@@ -8,7 +8,7 @@ use ecow::{eco_format, EcoString};
 use smallvec::SmallVec;
 use unicode_math_class::MathClass;
 
-use crate::diag::{At, SourceResult, StrResult};
+use crate::diag::{At, HintedStrResult, SourceResult, StrResult};
 use crate::foundations::{array, repr, NativeElement, Packed, Repr, Str, Type, Value};
 use crate::syntax::{Span, Spanned};
 
@@ -233,6 +233,12 @@ impl<T: IntoValue> IntoResult for StrResult<T> {
     }
 }
 
+impl<T: IntoValue> IntoResult for HintedStrResult<T> {
+    fn into_result(self, span: Span) -> SourceResult<Value> {
+        self.map(IntoValue::into_value).at(span)
+    }
+}
+
 impl<T: IntoValue> IntoResult for SourceResult<T> {
     fn into_result(self, _: Span) -> SourceResult<Value> {
         self.map(IntoValue::into_value)
diff --git a/crates/typst/src/foundations/dict.rs b/crates/typst/src/foundations/dict.rs
index 341504cb..59dd85c7 100644
--- a/crates/typst/src/foundations/dict.rs
+++ b/crates/typst/src/foundations/dict.rs
@@ -7,7 +7,7 @@ use ecow::{eco_format, EcoString};
 use indexmap::IndexMap;
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
-use crate::diag::StrResult;
+use crate::diag::{Hint, HintedStrResult, StrResult};
 use crate::foundations::{array, func, repr, scope, ty, Array, Repr, Str, Value};
 use crate::syntax::is_ident;
 use crate::util::ArcExt;
@@ -83,10 +83,11 @@ impl Dict {
     }
 
     /// Mutably borrow the value the given `key` maps to.
-    pub fn at_mut(&mut self, key: &str) -> StrResult<&mut Value> {
+    pub fn at_mut(&mut self, key: &str) -> HintedStrResult<&mut Value> {
         Arc::make_mut(&mut self.0)
             .get_mut(key)
-            .ok_or_else(|| missing_key_no_default(key))
+            .ok_or_else(|| missing_key(key))
+            .hint("use `insert` to add or update values")
     }
 
     /// Remove the value if the dictionary contains the given key.
@@ -354,7 +355,7 @@ fn missing_key(key: &str) -> EcoString {
     eco_format!("dictionary does not contain key {}", key.repr())
 }
 
-/// The missing key access error message when no default was fiven.
+/// The missing key access error message when no default was given.
 #[cold]
 fn missing_key_no_default(key: &str) -> EcoString {
     eco_format!(