Merging upstream version 126.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

9 files changed, 539 insertions, 131 deletions

diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustArithmetic.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustArithmetic.sys.mjs
index 1790f0effa..62766a45a4 100644
--- a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustArithmetic.sys.mjs
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustArithmetic.sys.mjs
@@ -329,7 +329,7 @@ export class FfiConverterTypeArithmeticError extends FfiConverterArrayBuffer {
             case 1:
                 return new IntegerOverflow(FfiConverterString.read(dataStream));
             default:
-                throw new Error("Unknown ArithmeticError variant");
+                throw new UniFFITypeError("Unknown ArithmeticError variant");
         }
     }
     static computeSize(value) {
@@ -338,14 +338,14 @@ export class FfiConverterTypeArithmeticError extends FfiConverterArrayBuffer {
         if (value instanceof IntegerOverflow) {
             return totalSize;
         }
-        throw new Error("Unknown ArithmeticError variant");
+        throw new UniFFITypeError("Unknown ArithmeticError variant");
     }
     static write(dataStream, value) {
         if (value instanceof IntegerOverflow) {
             dataStream.writeInt32(1);
             return;
         }
-        throw new Error("Unknown ArithmeticError variant");
+        throw new UniFFITypeError("Unknown ArithmeticError variant");
     }
 
     static errorClass = ArithmeticError;
@@ -377,7 +377,7 @@ export function add(a,b) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                35, // arithmetic:uniffi_arithmetical_fn_func_add
+                47, // arithmetic:uniffi_arithmetical_fn_func_add
                 FfiConverterU64.lower(a),
                 FfiConverterU64.lower(b),
             )
@@ -411,7 +411,7 @@ export function div(dividend,divisor) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                36, // arithmetic:uniffi_arithmetical_fn_func_div
+                48, // arithmetic:uniffi_arithmetical_fn_func_div
                 FfiConverterU64.lower(dividend),
                 FfiConverterU64.lower(divisor),
             )
@@ -445,7 +445,7 @@ export function equal(a,b) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                37, // arithmetic:uniffi_arithmetical_fn_func_equal
+                49, // arithmetic:uniffi_arithmetical_fn_func_equal
                 FfiConverterU64.lower(a),
                 FfiConverterU64.lower(b),
             )
@@ -479,7 +479,7 @@ export function sub(a,b) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                38, // arithmetic:uniffi_arithmetical_fn_func_sub
+                50, // arithmetic:uniffi_arithmetical_fn_func_sub
                 FfiConverterU64.lower(a),
                 FfiConverterU64.lower(b),
             )
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustCustomTypes.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustCustomTypes.sys.mjs
index 286c046fa6..581478cc8a 100644
--- a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustCustomTypes.sys.mjs
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustCustomTypes.sys.mjs
@@ -331,7 +331,7 @@ export class FfiConverterTypeCustomTypesDemo extends FfiConverterArrayBuffer {
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof CustomTypesDemo)) {
-            throw new TypeError(`Expected 'CustomTypesDemo', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'CustomTypesDemo', found '${typeof value}'`);
         }
         try {
             FfiConverterTypeUrl.checkType(value.url);
@@ -455,7 +455,7 @@ export function getCustomTypesDemo(demo) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                39, // custom_types:uniffi_uniffi_custom_types_fn_func_get_custom_types_demo
+                51, // custom_types:uniffi_uniffi_custom_types_fn_func_get_custom_types_demo
                 FfiConverterOptionalTypeCustomTypesDemo.lower(demo),
             )
         }
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustExternalTypes.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustExternalTypes.sys.mjs
index c01b1a58b3..88c9390225 100644
--- a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustExternalTypes.sys.mjs
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustExternalTypes.sys.mjs
@@ -381,7 +381,7 @@ export function gradient(value) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                40, // external_types:uniffi_uniffi_fixture_external_types_fn_func_gradient
+                52, // external_types:uniffi_uniffi_fixture_external_types_fn_func_gradient
                 FfiConverterOptionalTypeLine.lower(value),
             )
         }
@@ -414,7 +414,7 @@ export function intersection(ln1,ln2) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                41, // external_types:uniffi_uniffi_fixture_external_types_fn_func_intersection
+                53, // external_types:uniffi_uniffi_fixture_external_types_fn_func_intersection
                 FfiConverterTypeLine.lower(ln1),
                 FfiConverterTypeLine.lower(ln2),
             )
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustFixtureCallbacks.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustFixtureCallbacks.sys.mjs
index 75fe81a458..2b6b6b26ff 100644
--- a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustFixtureCallbacks.sys.mjs
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustFixtureCallbacks.sys.mjs
@@ -596,7 +596,7 @@ export function logEvenNumbers(logger,items) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                42, // fixture_callbacks:uniffi_uniffi_fixture_callbacks_fn_func_log_even_numbers
+                46, // fixture_callbacks:uniffi_uniffi_fixture_callbacks_fn_func_log_even_numbers
                 FfiConverterTypeLogger.lower(logger),
                 FfiConverterSequencei32.lower(items),
             )
@@ -630,7 +630,7 @@ export function logEvenNumbersMainThread(logger,items) {
                 throw e;
             }
             return UniFFIScaffolding.callSync(
-                43, // fixture_callbacks:uniffi_uniffi_fixture_callbacks_fn_func_log_even_numbers_main_thread
+                47, // fixture_callbacks:uniffi_uniffi_fixture_callbacks_fn_func_log_even_numbers_main_thread
                 FfiConverterTypeLogger.lower(logger),
                 FfiConverterSequencei32.lower(items),
             )
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustGeometry.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustGeometry.sys.mjs
index 1a7ebb287a..6ff9a25fa9 100644
--- a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustGeometry.sys.mjs
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustGeometry.sys.mjs
@@ -325,7 +325,7 @@ export class FfiConverterTypeLine extends FfiConverterArrayBuffer {
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof Line)) {
-            throw new TypeError(`Expected 'Line', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'Line', found '${typeof value}'`);
         }
         try {
             FfiConverterTypePoint.checkType(value.start);
@@ -398,7 +398,7 @@ export class FfiConverterTypePoint extends FfiConverterArrayBuffer {
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof Point)) {
-            throw new TypeError(`Expected 'Point', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'Point', found '${typeof value}'`);
         }
         try {
             FfiConverterF64.checkType(value.coordX);
@@ -474,7 +474,7 @@ export function gradient(ln) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                44, // geometry:uniffi_uniffi_geometry_fn_func_gradient
+                58, // geometry:uniffi_uniffi_geometry_fn_func_gradient
                 FfiConverterTypeLine.lower(ln),
             )
         }
@@ -507,7 +507,7 @@ export function intersection(ln1,ln2) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                45, // geometry:uniffi_uniffi_geometry_fn_func_intersection
+                59, // geometry:uniffi_uniffi_geometry_fn_func_intersection
                 FfiConverterTypeLine.lower(ln1),
                 FfiConverterTypeLine.lower(ln2),
             )
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustRefcounts.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustRefcounts.sys.mjs
new file mode 100644
index 0000000000..d8a598d150
--- /dev/null
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustRefcounts.sys.mjs
@@ -0,0 +1,388 @@
+// This file was autogenerated by the `uniffi-bindgen-gecko-js` crate.
+// Trust me, you don't want to mess with it!
+
+import { UniFFITypeError } from "resource://gre/modules/UniFFI.sys.mjs";
+
+
+
+// Objects intended to be used in the unit tests
+export var UnitTestObjs = {};
+
+// Write/Read data to/from an ArrayBuffer
+class ArrayBufferDataStream {
+    constructor(arrayBuffer) {
+        this.dataView = new DataView(arrayBuffer);
+        this.pos = 0;
+    }
+
+    readUint8() {
+        let rv = this.dataView.getUint8(this.pos);
+        this.pos += 1;
+        return rv;
+    }
+
+    writeUint8(value) {
+        this.dataView.setUint8(this.pos, value);
+        this.pos += 1;
+    }
+
+    readUint16() {
+        let rv = this.dataView.getUint16(this.pos);
+        this.pos += 2;
+        return rv;
+    }
+
+    writeUint16(value) {
+        this.dataView.setUint16(this.pos, value);
+        this.pos += 2;
+    }
+
+    readUint32() {
+        let rv = this.dataView.getUint32(this.pos);
+        this.pos += 4;
+        return rv;
+    }
+
+    writeUint32(value) {
+        this.dataView.setUint32(this.pos, value);
+        this.pos += 4;
+    }
+
+    readUint64() {
+        let rv = this.dataView.getBigUint64(this.pos);
+        this.pos += 8;
+        return Number(rv);
+    }
+
+    writeUint64(value) {
+        this.dataView.setBigUint64(this.pos, BigInt(value));
+        this.pos += 8;
+    }
+
+
+    readInt8() {
+        let rv = this.dataView.getInt8(this.pos);
+        this.pos += 1;
+        return rv;
+    }
+
+    writeInt8(value) {
+        this.dataView.setInt8(this.pos, value);
+        this.pos += 1;
+    }
+
+    readInt16() {
+        let rv = this.dataView.getInt16(this.pos);
+        this.pos += 2;
+        return rv;
+    }
+
+    writeInt16(value) {
+        this.dataView.setInt16(this.pos, value);
+        this.pos += 2;
+    }
+
+    readInt32() {
+        let rv = this.dataView.getInt32(this.pos);
+        this.pos += 4;
+        return rv;
+    }
+
+    writeInt32(value) {
+        this.dataView.setInt32(this.pos, value);
+        this.pos += 4;
+    }
+
+    readInt64() {
+        let rv = this.dataView.getBigInt64(this.pos);
+        this.pos += 8;
+        return Number(rv);
+    }
+
+    writeInt64(value) {
+        this.dataView.setBigInt64(this.pos, BigInt(value));
+        this.pos += 8;
+    }
+
+    readFloat32() {
+        let rv = this.dataView.getFloat32(this.pos);
+        this.pos += 4;
+        return rv;
+    }
+
+    writeFloat32(value) {
+        this.dataView.setFloat32(this.pos, value);
+        this.pos += 4;
+    }
+
+    readFloat64() {
+        let rv = this.dataView.getFloat64(this.pos);
+        this.pos += 8;
+        return rv;
+    }
+
+    writeFloat64(value) {
+        this.dataView.setFloat64(this.pos, value);
+        this.pos += 8;
+    }
+
+
+    writeString(value) {
+      const encoder = new TextEncoder();
+      // Note: in order to efficiently write this data, we first write the
+      // string data, reserving 4 bytes for the size.
+      const dest = new Uint8Array(this.dataView.buffer, this.pos + 4);
+      const encodeResult = encoder.encodeInto(value, dest);
+      if (encodeResult.read != value.length) {
+        throw new UniFFIError(
+            "writeString: out of space when writing to ArrayBuffer.  Did the computeSize() method returned the wrong result?"
+        );
+      }
+      const size = encodeResult.written;
+      // Next, go back and write the size before the string data
+      this.dataView.setUint32(this.pos, size);
+      // Finally, advance our position past both the size and string data
+      this.pos += size + 4;
+    }
+
+    readString() {
+      const decoder = new TextDecoder();
+      const size = this.readUint32();
+      const source = new Uint8Array(this.dataView.buffer, this.pos, size)
+      const value = decoder.decode(source);
+      this.pos += size;
+      return value;
+    }
+
+    // Reads a SingletonObject pointer from the data stream
+    // UniFFI Pointers are **always** 8 bytes long. That is enforced
+    // by the C++ and Rust Scaffolding code.
+    readPointerSingletonObject() {
+        const pointerId = 6; // refcounts:SingletonObject
+        const res = UniFFIScaffolding.readPointer(pointerId, this.dataView.buffer, this.pos);
+        this.pos += 8;
+        return res;
+    }
+
+    // Writes a SingletonObject pointer into the data stream
+    // UniFFI Pointers are **always** 8 bytes long. That is enforced
+    // by the C++ and Rust Scaffolding code.
+    writePointerSingletonObject(value) {
+        const pointerId = 6; // refcounts:SingletonObject
+        UniFFIScaffolding.writePointer(pointerId, value, this.dataView.buffer, this.pos);
+        this.pos += 8;
+    }
+    
+}
+
+function handleRustResult(result, liftCallback, liftErrCallback) {
+    switch (result.code) {
+        case "success":
+            return liftCallback(result.data);
+
+        case "error":
+            throw liftErrCallback(result.data);
+
+        case "internal-error":
+            let message = result.internalErrorMessage;
+            if (message) {
+                throw new UniFFIInternalError(message);
+            } else {
+                throw new UniFFIInternalError("Unknown error");
+            }
+
+        default:
+            throw new UniFFIError(`Unexpected status code: ${result.code}`);
+    }
+}
+
+class UniFFIError {
+    constructor(message) {
+        this.message = message;
+    }
+
+    toString() {
+        return `UniFFIError: ${this.message}`
+    }
+}
+
+class UniFFIInternalError extends UniFFIError {}
+
+// Base class for FFI converters
+class FfiConverter {
+    // throw `UniFFITypeError` if a value to be converted has an invalid type
+    static checkType(value) {
+        if (value === undefined ) {
+            throw new UniFFITypeError(`undefined`);
+        }
+        if (value === null ) {
+            throw new UniFFITypeError(`null`);
+        }
+    }
+}
+
+// Base class for FFI converters that lift/lower by reading/writing to an ArrayBuffer
+class FfiConverterArrayBuffer extends FfiConverter {
+    static lift(buf) {
+        return this.read(new ArrayBufferDataStream(buf));
+    }
+
+    static lower(value) {
+        const buf = new ArrayBuffer(this.computeSize(value));
+        const dataStream = new ArrayBufferDataStream(buf);
+        this.write(dataStream, value);
+        return buf;
+    }
+}
+
+// Symbols that are used to ensure that Object constructors
+// can only be used with a proper UniFFI pointer
+const uniffiObjectPtr = Symbol("uniffiObjectPtr");
+const constructUniffiObject = Symbol("constructUniffiObject");
+UnitTestObjs.uniffiObjectPtr = uniffiObjectPtr;
+
+// Export the FFIConverter object to make external types work.
+export class FfiConverterI32 extends FfiConverter {
+    static checkType(value) {
+        super.checkType(value);
+        if (!Number.isInteger(value)) {
+            throw new UniFFITypeError(`${value} is not an integer`);
+        }
+        if (value < -2147483648 || value > 2147483647) {
+            throw new UniFFITypeError(`${value} exceeds the I32 bounds`);
+        }
+    }
+    static computeSize() {
+        return 4;
+    }
+    static lift(value) {
+        return value;
+    }
+    static lower(value) {
+        return value;
+    }
+    static write(dataStream, value) {
+        dataStream.writeInt32(value)
+    }
+    static read(dataStream) {
+        return dataStream.readInt32()
+    }
+}
+
+// Export the FFIConverter object to make external types work.
+export class FfiConverterString extends FfiConverter {
+    static checkType(value) {
+        super.checkType(value);
+        if (typeof value !== "string") {
+            throw new UniFFITypeError(`${value} is not a string`);
+        }
+    }
+
+    static lift(buf) {
+        const decoder = new TextDecoder();
+        const utf8Arr = new Uint8Array(buf);
+        return decoder.decode(utf8Arr);
+    }
+    static lower(value) {
+        const encoder = new TextEncoder();
+        return encoder.encode(value).buffer;
+    }
+
+    static write(dataStream, value) {
+        dataStream.writeString(value);
+    }
+
+    static read(dataStream) {
+        return dataStream.readString();
+    }
+
+    static computeSize(value) {
+        const encoder = new TextEncoder();
+        return 4 + encoder.encode(value).length
+    }
+}
+
+export class SingletonObject {
+    // Use `init` to instantiate this class.
+    // DO NOT USE THIS CONSTRUCTOR DIRECTLY
+    constructor(opts) {
+        if (!Object.prototype.hasOwnProperty.call(opts, constructUniffiObject)) {
+            throw new UniFFIError("Attempting to construct an object using the JavaScript constructor directly" +
+            "Please use a UDL defined constructor, or the init function for the primary constructor")
+        }
+        if (!opts[constructUniffiObject] instanceof UniFFIPointer) {
+            throw new UniFFIError("Attempting to create a UniFFI object with a pointer that is not an instance of UniFFIPointer")
+        }
+        this[uniffiObjectPtr] = opts[constructUniffiObject];
+    }
+
+    method() {
+        const liftResult = (result) => undefined;
+        const liftError = null;
+        const functionCall = () => {
+            return UniFFIScaffolding.callSync(
+                55, // refcounts:uniffi_uniffi_fixture_refcounts_fn_method_singletonobject_method
+                FfiConverterTypeSingletonObject.lower(this),
+            )
+        }
+        return handleRustResult(functionCall(), liftResult, liftError);
+    }
+
+}
+
+// Export the FFIConverter object to make external types work.
+export class FfiConverterTypeSingletonObject extends FfiConverter {
+    static lift(value) {
+        const opts = {};
+        opts[constructUniffiObject] = value;
+        return new SingletonObject(opts);
+    }
+
+    static lower(value) {
+        const ptr = value[uniffiObjectPtr];
+        if (!(ptr instanceof UniFFIPointer)) {
+            throw new UniFFITypeError("Object is not a 'SingletonObject' instance");
+        }
+        return ptr;
+    }
+
+    static read(dataStream) {
+        return this.lift(dataStream.readPointerSingletonObject());
+    }
+
+    static write(dataStream, value) {
+        dataStream.writePointerSingletonObject(value[uniffiObjectPtr]);
+    }
+
+    static computeSize(value) {
+        return 8;
+    }
+}
+
+
+
+
+
+export function getJsRefcount() {
+
+        const liftResult = (result) => FfiConverterI32.lift(result);
+        const liftError = null;
+        const functionCall = () => {
+            return UniFFIScaffolding.callSync(
+                56, // refcounts:uniffi_uniffi_fixture_refcounts_fn_func_get_js_refcount
+            )
+        }
+        return handleRustResult(functionCall(), liftResult, liftError);
+}
+
+export function getSingleton() {
+
+        const liftResult = (result) => FfiConverterTypeSingletonObject.lift(result);
+        const liftError = null;
+        const functionCall = () => {
+            return UniFFIScaffolding.callSync(
+                57, // refcounts:uniffi_uniffi_fixture_refcounts_fn_func_get_singleton
+            )
+        }
+        return handleRustResult(functionCall(), liftResult, liftError);
+}
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustRondpoint.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustRondpoint.sys.mjs
index 1edb7ec608..f6db36163e 100644
--- a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustRondpoint.sys.mjs
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustRondpoint.sys.mjs
@@ -158,7 +158,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     readPointerOptionneur() {
-        const pointerId = 5; // rondpoint:Optionneur
+        const pointerId = 7; // rondpoint:Optionneur
         const res = UniFFIScaffolding.readPointer(pointerId, this.dataView.buffer, this.pos);
         this.pos += 8;
         return res;
@@ -168,7 +168,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     writePointerOptionneur(value) {
-        const pointerId = 5; // rondpoint:Optionneur
+        const pointerId = 7; // rondpoint:Optionneur
         UniFFIScaffolding.writePointer(pointerId, value, this.dataView.buffer, this.pos);
         this.pos += 8;
     }
@@ -178,7 +178,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     readPointerRetourneur() {
-        const pointerId = 6; // rondpoint:Retourneur
+        const pointerId = 8; // rondpoint:Retourneur
         const res = UniFFIScaffolding.readPointer(pointerId, this.dataView.buffer, this.pos);
         this.pos += 8;
         return res;
@@ -188,7 +188,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     writePointerRetourneur(value) {
-        const pointerId = 6; // rondpoint:Retourneur
+        const pointerId = 8; // rondpoint:Retourneur
         UniFFIScaffolding.writePointer(pointerId, value, this.dataView.buffer, this.pos);
         this.pos += 8;
     }
@@ -198,7 +198,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     readPointerStringifier() {
-        const pointerId = 7; // rondpoint:Stringifier
+        const pointerId = 9; // rondpoint:Stringifier
         const res = UniFFIScaffolding.readPointer(pointerId, this.dataView.buffer, this.pos);
         this.pos += 8;
         return res;
@@ -208,7 +208,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     writePointerStringifier(value) {
-        const pointerId = 7; // rondpoint:Stringifier
+        const pointerId = 9; // rondpoint:Stringifier
         UniFFIScaffolding.writePointer(pointerId, value, this.dataView.buffer, this.pos);
         this.pos += 8;
     }
@@ -620,7 +620,7 @@ export class Optionneur {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                46, // rondpoint:uniffi_uniffi_rondpoint_fn_constructor_optionneur_new
+                61, // rondpoint:uniffi_uniffi_rondpoint_fn_constructor_optionneur_new
             )
         }
         try {
@@ -642,7 +642,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                47, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_boolean
+                62, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_boolean
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterBool.lower(value),
             )
@@ -667,7 +667,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                48, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_enum
+                63, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_enum
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterTypeEnumeration.lower(value),
             )
@@ -692,7 +692,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                49, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_f32
+                64, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_f32
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterF32.lower(value),
             )
@@ -717,7 +717,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                50, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_f64
+                65, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_f64
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterF64.lower(value),
             )
@@ -742,7 +742,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                51, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i16_dec
+                66, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i16_dec
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterI16.lower(value),
             )
@@ -767,7 +767,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                52, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i16_hex
+                67, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i16_hex
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterI16.lower(value),
             )
@@ -792,7 +792,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                53, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i32_dec
+                68, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i32_dec
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterI32.lower(value),
             )
@@ -817,7 +817,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                54, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i32_hex
+                69, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i32_hex
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterI32.lower(value),
             )
@@ -842,7 +842,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                55, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i64_dec
+                70, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i64_dec
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterI64.lower(value),
             )
@@ -867,7 +867,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                56, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i64_hex
+                71, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i64_hex
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterI64.lower(value),
             )
@@ -892,7 +892,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                57, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i8_dec
+                72, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i8_dec
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterI8.lower(value),
             )
@@ -917,7 +917,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                58, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i8_hex
+                73, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_i8_hex
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterI8.lower(value),
             )
@@ -942,7 +942,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                59, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_null
+                74, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_null
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterOptionalstring.lower(value),
             )
@@ -967,7 +967,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                60, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_sequence
+                75, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_sequence
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterSequencestring.lower(value),
             )
@@ -992,7 +992,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                61, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_string
+                76, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_string
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterString.lower(value),
             )
@@ -1017,7 +1017,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                62, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u16_dec
+                77, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u16_dec
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU16.lower(value),
             )
@@ -1042,7 +1042,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                63, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u16_hex
+                78, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u16_hex
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU16.lower(value),
             )
@@ -1067,7 +1067,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                64, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u32_dec
+                79, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u32_dec
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU32.lower(value),
             )
@@ -1092,7 +1092,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                65, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u32_hex
+                80, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u32_hex
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU32.lower(value),
             )
@@ -1117,7 +1117,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                66, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u32_oct
+                81, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u32_oct
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU32.lower(value),
             )
@@ -1142,7 +1142,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                67, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u64_dec
+                82, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u64_dec
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU64.lower(value),
             )
@@ -1167,7 +1167,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                68, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u64_hex
+                83, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u64_hex
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU64.lower(value),
             )
@@ -1192,7 +1192,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                69, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u8_dec
+                84, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u8_dec
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU8.lower(value),
             )
@@ -1217,7 +1217,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                70, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u8_hex
+                85, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_u8_hex
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterU8.lower(value),
             )
@@ -1242,7 +1242,7 @@ export class Optionneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                71, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_zero
+                86, // rondpoint:uniffi_uniffi_rondpoint_fn_method_optionneur_sinon_zero
                 FfiConverterTypeOptionneur.lower(this),
                 FfiConverterOptionali32.lower(value),
             )
@@ -1265,7 +1265,11 @@ export class FfiConverterTypeOptionneur extends FfiConverter {
     }
 
     static lower(value) {
-        return value[uniffiObjectPtr];
+        const ptr = value[uniffiObjectPtr];
+        if (!(ptr instanceof UniFFIPointer)) {
+            throw new UniFFITypeError("Object is not a 'Optionneur' instance");
+        }
+        return ptr;
     }
 
     static read(dataStream) {
@@ -1305,7 +1309,7 @@ export class Retourneur {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                72, // rondpoint:uniffi_uniffi_rondpoint_fn_constructor_retourneur_new
+                88, // rondpoint:uniffi_uniffi_rondpoint_fn_constructor_retourneur_new
             )
         }
         try {
@@ -1327,7 +1331,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                73, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_boolean
+                89, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_boolean
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterBool.lower(value),
             )
@@ -1352,7 +1356,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                74, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_double
+                90, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_double
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterF64.lower(value),
             )
@@ -1377,7 +1381,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                75, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_float
+                91, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_float
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterF32.lower(value),
             )
@@ -1402,7 +1406,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                76, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_i16
+                92, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_i16
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterI16.lower(value),
             )
@@ -1427,7 +1431,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                77, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_i32
+                93, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_i32
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterI32.lower(value),
             )
@@ -1452,7 +1456,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                78, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_i64
+                94, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_i64
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterI64.lower(value),
             )
@@ -1477,7 +1481,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                79, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_i8
+                95, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_i8
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterI8.lower(value),
             )
@@ -1502,7 +1506,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                80, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_nombres
+                96, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_nombres
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterTypeDictionnaireNombres.lower(value),
             )
@@ -1527,7 +1531,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                81, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_nombres_signes
+                97, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_nombres_signes
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterTypeDictionnaireNombresSignes.lower(value),
             )
@@ -1552,7 +1556,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                82, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_optionneur_dictionnaire
+                98, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_optionneur_dictionnaire
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterTypeOptionneurDictionnaire.lower(value),
             )
@@ -1577,7 +1581,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                83, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_string
+                99, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_string
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterString.lower(value),
             )
@@ -1602,7 +1606,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                84, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_u16
+                100, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_u16
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterU16.lower(value),
             )
@@ -1627,7 +1631,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                85, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_u32
+                101, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_u32
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterU32.lower(value),
             )
@@ -1652,7 +1656,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                86, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_u64
+                102, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_u64
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterU64.lower(value),
             )
@@ -1677,7 +1681,7 @@ export class Retourneur {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                87, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_u8
+                103, // rondpoint:uniffi_uniffi_rondpoint_fn_method_retourneur_identique_u8
                 FfiConverterTypeRetourneur.lower(this),
                 FfiConverterU8.lower(value),
             )
@@ -1700,7 +1704,11 @@ export class FfiConverterTypeRetourneur extends FfiConverter {
     }
 
     static lower(value) {
-        return value[uniffiObjectPtr];
+        const ptr = value[uniffiObjectPtr];
+        if (!(ptr instanceof UniFFIPointer)) {
+            throw new UniFFITypeError("Object is not a 'Retourneur' instance");
+        }
+        return ptr;
     }
 
     static read(dataStream) {
@@ -1740,7 +1748,7 @@ export class Stringifier {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                88, // rondpoint:uniffi_uniffi_rondpoint_fn_constructor_stringifier_new
+                105, // rondpoint:uniffi_uniffi_rondpoint_fn_constructor_stringifier_new
             )
         }
         try {
@@ -1762,7 +1770,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                89, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_boolean
+                106, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_boolean
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterBool.lower(value),
             )
@@ -1787,7 +1795,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                90, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_double
+                107, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_double
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterF64.lower(value),
             )
@@ -1812,7 +1820,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                91, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_float
+                108, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_float
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterF32.lower(value),
             )
@@ -1837,7 +1845,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                92, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_i16
+                109, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_i16
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterI16.lower(value),
             )
@@ -1862,7 +1870,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                93, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_i32
+                110, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_i32
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterI32.lower(value),
             )
@@ -1887,7 +1895,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                94, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_i64
+                111, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_i64
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterI64.lower(value),
             )
@@ -1912,7 +1920,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                95, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_i8
+                112, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_i8
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterI8.lower(value),
             )
@@ -1937,7 +1945,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                96, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_u16
+                113, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_u16
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterU16.lower(value),
             )
@@ -1962,7 +1970,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                97, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_u32
+                114, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_u32
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterU32.lower(value),
             )
@@ -1987,7 +1995,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                98, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_u64
+                115, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_u64
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterU64.lower(value),
             )
@@ -2012,7 +2020,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                99, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_u8
+                116, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_to_string_u8
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterU8.lower(value),
             )
@@ -2037,7 +2045,7 @@ export class Stringifier {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                100, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_well_known_string
+                117, // rondpoint:uniffi_uniffi_rondpoint_fn_method_stringifier_well_known_string
                 FfiConverterTypeStringifier.lower(this),
                 FfiConverterString.lower(value),
             )
@@ -2060,7 +2068,11 @@ export class FfiConverterTypeStringifier extends FfiConverter {
     }
 
     static lower(value) {
-        return value[uniffiObjectPtr];
+        const ptr = value[uniffiObjectPtr];
+        if (!(ptr instanceof UniFFIPointer)) {
+            throw new UniFFITypeError("Object is not a 'Stringifier' instance");
+        }
+        return ptr;
     }
 
     static read(dataStream) {
@@ -2154,7 +2166,7 @@ export class FfiConverterTypeDictionnaire extends FfiConverterArrayBuffer {
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof Dictionnaire)) {
-            throw new TypeError(`Expected 'Dictionnaire', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'Dictionnaire', found '${typeof value}'`);
         }
         try {
             FfiConverterTypeEnumeration.checkType(value.un);
@@ -2269,7 +2281,7 @@ export class FfiConverterTypeDictionnaireNombres extends FfiConverterArrayBuffer
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof DictionnaireNombres)) {
-            throw new TypeError(`Expected 'DictionnaireNombres', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'DictionnaireNombres', found '${typeof value}'`);
         }
         try {
             FfiConverterU8.checkType(value.petitNombre);
@@ -2384,7 +2396,7 @@ export class FfiConverterTypeDictionnaireNombresSignes extends FfiConverterArray
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof DictionnaireNombresSignes)) {
-            throw new TypeError(`Expected 'DictionnaireNombresSignes', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'DictionnaireNombresSignes', found '${typeof value}'`);
         }
         try {
             FfiConverterI8.checkType(value.petitNombre);
@@ -2642,7 +2654,7 @@ export class FfiConverterTypeOptionneurDictionnaire extends FfiConverterArrayBuf
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof OptionneurDictionnaire)) {
-            throw new TypeError(`Expected 'OptionneurDictionnaire', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'OptionneurDictionnaire', found '${typeof value}'`);
         }
         try {
             FfiConverterI8.checkType(value.i8Var);
@@ -2806,7 +2818,7 @@ export class FfiConverterTypeminusculeMajusculeDict extends FfiConverterArrayBuf
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof MinusculeMajusculeDict)) {
-            throw new TypeError(`Expected 'MinusculeMajusculeDict', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'MinusculeMajusculeDict', found '${typeof value}'`);
         }
         try {
             FfiConverterBool.checkType(value.minusculeMajusculeField);
@@ -2838,7 +2850,7 @@ export class FfiConverterTypeEnumeration extends FfiConverterArrayBuffer {
             case 3:
                 return Enumeration.TROIS
             default:
-                return new Error("Unknown Enumeration variant");
+                throw new UniFFITypeError("Unknown Enumeration variant");
         }
     }
 
@@ -2855,7 +2867,7 @@ export class FfiConverterTypeEnumeration extends FfiConverterArrayBuffer {
             dataStream.writeInt32(3);
             return;
         }
-        return new Error("Unknown Enumeration variant");
+        throw new UniFFITypeError("Unknown Enumeration variant");
     }
 
     static computeSize(value) {
@@ -2914,7 +2926,7 @@ export class FfiConverterTypeEnumerationAvecDonnees extends FfiConverterArrayBuf
                     FfiConverterString.read(dataStream)
                     );
             default:
-                return new Error("Unknown EnumerationAvecDonnees variant");
+                throw new UniFFITypeError("Unknown EnumerationAvecDonnees variant");
         }
     }
 
@@ -2934,7 +2946,7 @@ export class FfiConverterTypeEnumerationAvecDonnees extends FfiConverterArrayBuf
             FfiConverterString.write(dataStream, value.second);
             return;
         }
-        return new Error("Unknown EnumerationAvecDonnees variant");
+        throw new UniFFITypeError("Unknown EnumerationAvecDonnees variant");
     }
 
     static computeSize(value) {
@@ -2952,7 +2964,7 @@ export class FfiConverterTypeEnumerationAvecDonnees extends FfiConverterArrayBuf
             totalSize += FfiConverterString.computeSize(value.second);
             return totalSize;
         }
-        return new Error("Unknown EnumerationAvecDonnees variant");
+        throw new UniFFITypeError("Unknown EnumerationAvecDonnees variant");
     }
 
     static checkType(value) {
@@ -2976,7 +2988,7 @@ export class FfiConverterTypeminusculeMajusculeEnum extends FfiConverterArrayBuf
             case 1:
                 return MinusculeMajusculeEnum.MINUSCULE_MAJUSCULE_VARIANT
             default:
-                return new Error("Unknown MinusculeMajusculeEnum variant");
+                throw new UniFFITypeError("Unknown MinusculeMajusculeEnum variant");
         }
     }
 
@@ -2985,7 +2997,7 @@ export class FfiConverterTypeminusculeMajusculeEnum extends FfiConverterArrayBuf
             dataStream.writeInt32(1);
             return;
         }
-        return new Error("Unknown MinusculeMajusculeEnum variant");
+        throw new UniFFITypeError("Unknown MinusculeMajusculeEnum variant");
     }
 
     static computeSize(value) {
@@ -3272,7 +3284,7 @@ export function copieCarte(c) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                101, // rondpoint:uniffi_uniffi_rondpoint_fn_func_copie_carte
+                118, // rondpoint:uniffi_uniffi_rondpoint_fn_func_copie_carte
                 FfiConverterMapStringTypeEnumerationAvecDonnees.lower(c),
             )
         }
@@ -3297,7 +3309,7 @@ export function copieDictionnaire(d) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                102, // rondpoint:uniffi_uniffi_rondpoint_fn_func_copie_dictionnaire
+                119, // rondpoint:uniffi_uniffi_rondpoint_fn_func_copie_dictionnaire
                 FfiConverterTypeDictionnaire.lower(d),
             )
         }
@@ -3322,7 +3334,7 @@ export function copieEnumeration(e) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                103, // rondpoint:uniffi_uniffi_rondpoint_fn_func_copie_enumeration
+                120, // rondpoint:uniffi_uniffi_rondpoint_fn_func_copie_enumeration
                 FfiConverterTypeEnumeration.lower(e),
             )
         }
@@ -3347,7 +3359,7 @@ export function copieEnumerations(e) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                104, // rondpoint:uniffi_uniffi_rondpoint_fn_func_copie_enumerations
+                121, // rondpoint:uniffi_uniffi_rondpoint_fn_func_copie_enumerations
                 FfiConverterSequenceTypeEnumeration.lower(e),
             )
         }
@@ -3372,7 +3384,7 @@ export function switcheroo(b) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                105, // rondpoint:uniffi_uniffi_rondpoint_fn_func_switcheroo
+                122, // rondpoint:uniffi_uniffi_rondpoint_fn_func_switcheroo
                 FfiConverterBool.lower(b),
             )
         }
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustSprites.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustSprites.sys.mjs
index b404af06b1..c25a488009 100644
--- a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustSprites.sys.mjs
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustSprites.sys.mjs
@@ -158,7 +158,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     readPointerSprite() {
-        const pointerId = 8; // sprites:Sprite
+        const pointerId = 10; // sprites:Sprite
         const res = UniFFIScaffolding.readPointer(pointerId, this.dataView.buffer, this.pos);
         this.pos += 8;
         return res;
@@ -168,7 +168,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     writePointerSprite(value) {
-        const pointerId = 8; // sprites:Sprite
+        const pointerId = 10; // sprites:Sprite
         UniFFIScaffolding.writePointer(pointerId, value, this.dataView.buffer, this.pos);
         this.pos += 8;
     }
@@ -325,7 +325,7 @@ export class Sprite {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                106, // sprites:uniffi_uniffi_sprites_fn_constructor_sprite_new
+                124, // sprites:uniffi_uniffi_sprites_fn_constructor_sprite_new
                 FfiConverterOptionalTypePoint.lower(initialPosition),
             )
         }
@@ -361,7 +361,7 @@ export class Sprite {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                107, // sprites:uniffi_uniffi_sprites_fn_constructor_sprite_new_relative_to
+                125, // sprites:uniffi_uniffi_sprites_fn_constructor_sprite_new_relative_to
                 FfiConverterTypePoint.lower(reference),
                 FfiConverterTypeVector.lower(direction),
             )
@@ -377,7 +377,7 @@ export class Sprite {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                108, // sprites:uniffi_uniffi_sprites_fn_method_sprite_get_position
+                126, // sprites:uniffi_uniffi_sprites_fn_method_sprite_get_position
                 FfiConverterTypeSprite.lower(this),
             )
         }
@@ -401,7 +401,7 @@ export class Sprite {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                109, // sprites:uniffi_uniffi_sprites_fn_method_sprite_move_by
+                127, // sprites:uniffi_uniffi_sprites_fn_method_sprite_move_by
                 FfiConverterTypeSprite.lower(this),
                 FfiConverterTypeVector.lower(direction),
             )
@@ -426,7 +426,7 @@ export class Sprite {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                110, // sprites:uniffi_uniffi_sprites_fn_method_sprite_move_to
+                128, // sprites:uniffi_uniffi_sprites_fn_method_sprite_move_to
                 FfiConverterTypeSprite.lower(this),
                 FfiConverterTypePoint.lower(position),
             )
@@ -449,7 +449,11 @@ export class FfiConverterTypeSprite extends FfiConverter {
     }
 
     static lower(value) {
-        return value[uniffiObjectPtr];
+        const ptr = value[uniffiObjectPtr];
+        if (!(ptr instanceof UniFFIPointer)) {
+            throw new UniFFITypeError("Object is not a 'Sprite' instance");
+        }
+        return ptr;
     }
 
     static read(dataStream) {
@@ -517,7 +521,7 @@ export class FfiConverterTypePoint extends FfiConverterArrayBuffer {
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof Point)) {
-            throw new TypeError(`Expected 'Point', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'Point', found '${typeof value}'`);
         }
         try {
             FfiConverterF64.checkType(value.x);
@@ -590,7 +594,7 @@ export class FfiConverterTypeVector extends FfiConverterArrayBuffer {
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof Vector)) {
-            throw new TypeError(`Expected 'Vector', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'Vector', found '${typeof value}'`);
         }
         try {
             FfiConverterF64.checkType(value.dx);
@@ -674,7 +678,7 @@ export function translate(position,direction) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                111, // sprites:uniffi_uniffi_sprites_fn_func_translate
+                129, // sprites:uniffi_uniffi_sprites_fn_func_translate
                 FfiConverterTypePoint.lower(position),
                 FfiConverterTypeVector.lower(direction),
             )
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustTodolist.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustTodolist.sys.mjs
index 59996b78fa..ddeccc9bf2 100644
--- a/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustTodolist.sys.mjs
+++ b/toolkit/components/uniffi-bindgen-gecko-js/fixtures/generated/RustTodolist.sys.mjs
@@ -158,7 +158,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     readPointerTodoList() {
-        const pointerId = 9; // todolist:TodoList
+        const pointerId = 11; // todolist:TodoList
         const res = UniFFIScaffolding.readPointer(pointerId, this.dataView.buffer, this.pos);
         this.pos += 8;
         return res;
@@ -168,7 +168,7 @@ class ArrayBufferDataStream {
     // UniFFI Pointers are **always** 8 bytes long. That is enforced
     // by the C++ and Rust Scaffolding code.
     writePointerTodoList(value) {
-        const pointerId = 9; // todolist:TodoList
+        const pointerId = 11; // todolist:TodoList
         UniFFIScaffolding.writePointer(pointerId, value, this.dataView.buffer, this.pos);
         this.pos += 8;
     }
@@ -298,7 +298,7 @@ export class TodoList {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                112, // todolist:uniffi_uniffi_todolist_fn_constructor_todolist_new
+                131, // todolist:uniffi_uniffi_todolist_fn_constructor_todolist_new
             )
         }
         try {
@@ -320,7 +320,7 @@ export class TodoList {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                113, // todolist:uniffi_uniffi_todolist_fn_method_todolist_add_entries
+                132, // todolist:uniffi_uniffi_todolist_fn_method_todolist_add_entries
                 FfiConverterTypeTodoList.lower(this),
                 FfiConverterSequenceTypeTodoEntry.lower(entries),
             )
@@ -345,7 +345,7 @@ export class TodoList {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                114, // todolist:uniffi_uniffi_todolist_fn_method_todolist_add_entry
+                133, // todolist:uniffi_uniffi_todolist_fn_method_todolist_add_entry
                 FfiConverterTypeTodoList.lower(this),
                 FfiConverterTypeTodoEntry.lower(entry),
             )
@@ -370,7 +370,7 @@ export class TodoList {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                115, // todolist:uniffi_uniffi_todolist_fn_method_todolist_add_item
+                134, // todolist:uniffi_uniffi_todolist_fn_method_todolist_add_item
                 FfiConverterTypeTodoList.lower(this),
                 FfiConverterString.lower(todo),
             )
@@ -395,7 +395,7 @@ export class TodoList {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                116, // todolist:uniffi_uniffi_todolist_fn_method_todolist_add_items
+                135, // todolist:uniffi_uniffi_todolist_fn_method_todolist_add_items
                 FfiConverterTypeTodoList.lower(this),
                 FfiConverterSequencestring.lower(items),
             )
@@ -420,7 +420,7 @@ export class TodoList {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                117, // todolist:uniffi_uniffi_todolist_fn_method_todolist_clear_item
+                136, // todolist:uniffi_uniffi_todolist_fn_method_todolist_clear_item
                 FfiConverterTypeTodoList.lower(this),
                 FfiConverterString.lower(todo),
             )
@@ -437,7 +437,7 @@ export class TodoList {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                118, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_entries
+                137, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_entries
                 FfiConverterTypeTodoList.lower(this),
             )
         }
@@ -453,7 +453,7 @@ export class TodoList {
         const liftError = (data) => FfiConverterTypeTodoError.lift(data);
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                119, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_first
+                138, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_first
                 FfiConverterTypeTodoList.lower(this),
             )
         }
@@ -469,7 +469,7 @@ export class TodoList {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                120, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_items
+                139, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_items
                 FfiConverterTypeTodoList.lower(this),
             )
         }
@@ -485,7 +485,7 @@ export class TodoList {
         const liftError = (data) => FfiConverterTypeTodoError.lift(data);
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                121, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_last
+                140, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_last
                 FfiConverterTypeTodoList.lower(this),
             )
         }
@@ -501,7 +501,7 @@ export class TodoList {
         const liftError = (data) => FfiConverterTypeTodoError.lift(data);
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                122, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_last_entry
+                141, // todolist:uniffi_uniffi_todolist_fn_method_todolist_get_last_entry
                 FfiConverterTypeTodoList.lower(this),
             )
         }
@@ -517,7 +517,7 @@ export class TodoList {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                123, // todolist:uniffi_uniffi_todolist_fn_method_todolist_make_default
+                142, // todolist:uniffi_uniffi_todolist_fn_method_todolist_make_default
                 FfiConverterTypeTodoList.lower(this),
             )
         }
@@ -539,7 +539,11 @@ export class FfiConverterTypeTodoList extends FfiConverter {
     }
 
     static lower(value) {
-        return value[uniffiObjectPtr];
+        const ptr = value[uniffiObjectPtr];
+        if (!(ptr instanceof UniFFIPointer)) {
+            throw new UniFFITypeError("Object is not a 'TodoList' instance");
+        }
+        return ptr;
     }
 
     static read(dataStream) {
@@ -594,7 +598,7 @@ export class FfiConverterTypeTodoEntry extends FfiConverterArrayBuffer {
     static checkType(value) {
         super.checkType(value);
         if (!(value instanceof TodoEntry)) {
-            throw new TypeError(`Expected 'TodoEntry', found '${typeof value}'`);
+            throw new UniFFITypeError(`Expected 'TodoEntry', found '${typeof value}'`);
         }
         try {
             FfiConverterString.checkType(value.text);
@@ -683,7 +687,7 @@ export class FfiConverterTypeTodoError extends FfiConverterArrayBuffer {
             case 5:
                 return new DeligatedError(FfiConverterString.read(dataStream));
             default:
-                throw new Error("Unknown TodoError variant");
+                throw new UniFFITypeError("Unknown TodoError variant");
         }
     }
     static computeSize(value) {
@@ -704,7 +708,7 @@ export class FfiConverterTypeTodoError extends FfiConverterArrayBuffer {
         if (value instanceof DeligatedError) {
             return totalSize;
         }
-        throw new Error("Unknown TodoError variant");
+        throw new UniFFITypeError("Unknown TodoError variant");
     }
     static write(dataStream, value) {
         if (value instanceof TodoDoesNotExist) {
@@ -727,7 +731,7 @@ export class FfiConverterTypeTodoError extends FfiConverterArrayBuffer {
             dataStream.writeInt32(5);
             return;
         }
-        throw new Error("Unknown TodoError variant");
+        throw new UniFFITypeError("Unknown TodoError variant");
     }
 
     static errorClass = TodoError;
@@ -876,7 +880,7 @@ export function createEntryWith(todo) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                124, // todolist:uniffi_uniffi_todolist_fn_func_create_entry_with
+                143, // todolist:uniffi_uniffi_todolist_fn_func_create_entry_with
                 FfiConverterString.lower(todo),
             )
         }
@@ -893,7 +897,7 @@ export function getDefaultList() {
         const liftError = null;
         const functionCall = () => {
             return UniFFIScaffolding.callAsync(
-                125, // todolist:uniffi_uniffi_todolist_fn_func_get_default_list
+                144, // todolist:uniffi_uniffi_todolist_fn_func_get_default_list
             )
         }
         try {
@@ -917,7 +921,7 @@ export function setDefaultList(list) {
                 throw e;
             }
             return UniFFIScaffolding.callAsync(
-                126, // todolist:uniffi_uniffi_todolist_fn_func_set_default_list
+                145, // todolist:uniffi_uniffi_todolist_fn_func_set_default_list
                 FfiConverterTypeTodoList.lower(list),
             )
         }