7 files changed, 18 insertions, 9 deletions
diff --git a/serde_v8/magic/bigint.rs b/serde_v8/magic/bigint.rs
index 69828747f..330803daf 100644
--- a/serde_v8/magic/bigint.rs
+++ b/serde_v8/magic/bigint.rs
@@ -5,6 +5,7 @@ use smallvec::SmallVec;
 
 use super::transl8::FromV8;
 use super::transl8::ToV8;
+use crate::error::value_to_type_str;
 use crate::magic::transl8::impl_magic;
 use crate::Error;
 
@@ -42,7 +43,7 @@ impl FromV8 for BigInt {
     value: v8::Local<v8::Value>,
   ) -> Result<Self, crate::Error> {
     let v8bigint = v8::Local::<v8::BigInt>::try_from(value)
-      .map_err(|_| Error::ExpectedBigInt)?;
+      .map_err(|_| Error::ExpectedBigInt(value_to_type_str(value)))?;
     let word_count = v8bigint.word_count();
     let mut words: SmallVec<[u64; 1]> = smallvec![0u64; word_count];
     let (sign_bit, _words) = v8bigint.to_words_array(&mut words);
diff --git a/serde_v8/magic/bytestring.rs b/serde_v8/magic/bytestring.rs
index 77771698f..3baa704e5 100644
--- a/serde_v8/magic/bytestring.rs
+++ b/serde_v8/magic/bytestring.rs
@@ -1,6 +1,7 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 use super::transl8::FromV8;
 use super::transl8::ToV8;
+use crate::error::value_to_type_str;
 use crate::magic::transl8::impl_magic;
 use crate::Error;
 use smallvec::SmallVec;
@@ -49,7 +50,7 @@ impl FromV8 for ByteString {
     value: v8::Local<v8::Value>,
   ) -> Result<Self, crate::Error> {
     let v8str = v8::Local::<v8::String>::try_from(value)
-      .map_err(|_| Error::ExpectedString)?;
+      .map_err(|_| Error::ExpectedString(value_to_type_str(value)))?;
     if !v8str.contains_only_onebyte() {
       return Err(Error::ExpectedLatin1);
     }
diff --git a/serde_v8/magic/detached_buffer.rs b/serde_v8/magic/detached_buffer.rs
index 7ee4dfb21..bc4b3de67 100644
--- a/serde_v8/magic/detached_buffer.rs
+++ b/serde_v8/magic/detached_buffer.rs
@@ -8,6 +8,7 @@ use super::transl8::FromV8;
 use super::transl8::ToV8;
 use super::v8slice::to_ranged_buffer;
 use super::v8slice::V8Slice;
+use crate::error::value_to_type_str;
 use crate::magic::transl8::impl_magic;
 
 // A buffer that detaches when deserialized from JS
@@ -57,10 +58,10 @@ impl FromV8 for DetachedBuffer {
     scope: &mut v8::HandleScope,
     value: v8::Local<v8::Value>,
   ) -> Result<Self, crate::Error> {
-    let (b, range) =
-      to_ranged_buffer(scope, value).or(Err(crate::Error::ExpectedBuffer))?;
+    let (b, range) = to_ranged_buffer(scope, value)
+      .map_err(|_| crate::Error::ExpectedBuffer(value_to_type_str(value)))?;
     if !b.is_detachable() {
-      return Err(crate::Error::ExpectedDetachable);
+      return Err(crate::Error::ExpectedDetachable(value_to_type_str(value)));
     }
     let store = b.get_backing_store();
     b.detach(None); // Detach
diff --git a/serde_v8/magic/external_pointer.rs b/serde_v8/magic/external_pointer.rs
index fca6028d6..e22e41a01 100644
--- a/serde_v8/magic/external_pointer.rs
+++ b/serde_v8/magic/external_pointer.rs
@@ -2,6 +2,8 @@
 
 use std::ffi::c_void;
 
+use crate::error::value_to_type_str;
+
 use super::transl8::impl_magic;
 use super::transl8::FromV8;
 use super::transl8::ToV8;
@@ -38,7 +40,7 @@ impl FromV8 for ExternalPointer {
     } else if let Ok(external) = v8::Local::<v8::External>::try_from(value) {
       Ok(ExternalPointer(external.value()))
     } else {
-      Err(crate::Error::ExpectedExternal)
+      Err(crate::Error::ExpectedExternal(value_to_type_str(value)))
     }
   }
 }
diff --git a/serde_v8/magic/string_or_buffer.rs b/serde_v8/magic/string_or_buffer.rs
index 04ce08be2..8b1a06dbc 100644
--- a/serde_v8/magic/string_or_buffer.rs
+++ b/serde_v8/magic/string_or_buffer.rs
@@ -2,6 +2,7 @@
 use super::buffer::ZeroCopyBuf;
 use super::transl8::FromV8;
 use super::transl8::ToV8;
+use crate::error::value_to_type_str;
 use crate::magic::transl8::impl_magic;
 use crate::Error;
 use std::ops::Deref;
@@ -73,7 +74,7 @@ impl FromV8 for StringOrBuffer {
     } else if let Ok(s) = crate::from_v8(scope, value) {
       return Ok(Self::String(s));
     }
-    Err(Error::ExpectedBuffer)
+    Err(Error::ExpectedBuffer(value_to_type_str(value)))
   }
 }
 
diff --git a/serde_v8/magic/u16string.rs b/serde_v8/magic/u16string.rs
index 57e3fd0f6..04d742da9 100644
--- a/serde_v8/magic/u16string.rs
+++ b/serde_v8/magic/u16string.rs
@@ -1,5 +1,6 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
+use crate::error::value_to_type_str;
 use crate::Error;
 
 use super::transl8::impl_magic;
@@ -37,7 +38,7 @@ impl FromV8 for U16String {
     value: v8::Local<v8::Value>,
   ) -> Result<Self, crate::Error> {
     let v8str = v8::Local::<v8::String>::try_from(value)
-      .map_err(|_| Error::ExpectedString)?;
+      .map_err(|_| Error::ExpectedString(value_to_type_str(value)))?;
     let len = v8str.length();
     let mut buffer = Vec::with_capacity(len);
     #[allow(clippy::uninit_vec)]
diff --git a/serde_v8/magic/v8slice.rs b/serde_v8/magic/v8slice.rs
index 384ccf5c5..073e75235 100644
--- a/serde_v8/magic/v8slice.rs
+++ b/serde_v8/magic/v8slice.rs
@@ -5,6 +5,8 @@ use std::ops::DerefMut;
 use std::ops::Range;
 use std::rc::Rc;
 
+use crate::error::value_to_type_str;
+
 use super::rawbytes;
 use super::transl8::FromV8;
 
@@ -91,7 +93,7 @@ impl FromV8 for V8Slice {
   ) -> Result<Self, crate::Error> {
     to_ranged_buffer(scope, value)
       .and_then(|(b, r)| Self::from_buffer(b, r))
-      .map_err(|_| crate::Error::ExpectedBuffer)
+      .map_err(|_| crate::Error::ExpectedBuffer(value_to_type_str(value)))
   }
 }