explicit prelude + fixing test error messages

crates/ink/codegen/src/generator/dispatch.rs

@@ -582,6 +582,8 @@ impl Dispatch<'_> {
 
             quote_spanned!(constructor_span=>
                 Self::#constructor_ident(input) => {
+                    use ::core::default::Default;
+
                     if #any_constructor_accept_payment && #deny_payment {
                         ::ink::codegen::deny_payment::<
                             <#storage_ident as ::ink::reflect::ContractEnv>::Env>()?;

crates/ink/codegen/src/generator/metadata.rs

@@ -338,7 +338,7 @@ impl Metadata<'_> {
         quote_spanned!(span=>
             ::ink::metadata::ReturnTypeSpec::new(
                 if #constructor_info ::IS_RESULT {
-                    Some(::ink::metadata::TypeSpec::with_name_str::<
+                    ::core::option::Option::Some(::ink::metadata::TypeSpec::with_name_str::<
                         ::core::result::Result<
                             (),
                             #constructor_info ::Error
@@ -348,7 +348,7 @@ impl Metadata<'_> {
                     )
                 )
                 } else {
-                    None
+                    ::core::option::Option::None
                 }
             )
         )

crates/ink/tests/ui/contract/fail/constructor-return-result-invalid.stderr

@@ -1,14 +1,9 @@
-error[E0277]: the trait bound `codegen::dispatch::execution::private::Seal<Result<u8, contract::Error>>: codegen::dispatch::execution::ConstructorReturnType<Contract>` is not satisfied
+error[E0277]: the trait bound `ConstructorOutputValue<Result<u8, contract::Error>>: ConstructorOutput<Contract>` is not satisfied
   --> tests/ui/contract/fail/constructor-return-result-invalid.rs:14:9
    |
 14 |         pub fn constructor() -> Result<u8, Error> {
-   |         ^^^ the trait `codegen::dispatch::execution::ConstructorReturnType<Contract>` is not implemented for `codegen::dispatch::execution::private::Seal<Result<u8, contract::Error>>`
+   |         ^^^ the trait `ConstructorOutput<Contract>` is not implemented for `ConstructorOutputValue<Result<u8, contract::Error>>`
    |
-   = help: the following other types implement trait `codegen::dispatch::execution::ConstructorReturnType<C>`:
-             codegen::dispatch::execution::private::Seal<C>
-             codegen::dispatch::execution::private::Seal<Result<C, E>>
-note: required by a bound in `execute_constructor`
-  --> src/codegen/dispatch/execution.rs
-   |
-   |     private::Seal<R>: ConstructorReturnType<Contract>,
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `execute_constructor`
+   = help: the following other types implement trait `ConstructorOutput<C>`:
+             ConstructorOutputValue<C>
+             ConstructorOutputValue<Result<C, E>>

crates/ink/tests/ui/contract/fail/constructor-return-result-non-codec-error.stderr

@@ -1,31 +1,21 @@
-error[E0277]: the trait bound `contract::Error: WrapperTypeEncode` is not satisfied
+error[E0277]: the trait bound `Result<(), &contract::Error>: Encode` is not satisfied
   --> tests/ui/contract/fail/constructor-return-result-non-codec-error.rs:13:9
    |
 13 |         pub fn constructor() -> Result<Self, Error> {
-   |         ^^^ the trait `WrapperTypeEncode` is not implemented for `contract::Error`
+   |         ^^^ the trait `Encode` is not implemented for `Result<(), &contract::Error>`
    |
-   = help: the following other types implement trait `WrapperTypeEncode`:
-             &T
-             &mut T
-             Arc<T>
-             Box<T>
-             Cow<'a, T>
-             Rc<T>
-             String
-             Vec<T>
-             parity_scale_codec::Ref<'a, T, U>
-   = note: required for `contract::Error` to implement `Encode`
-note: required by a bound in `execute_constructor`
-  --> src/codegen/dispatch/execution.rs
+   = help: the trait `Encode` is implemented for `Result<T, E>`
+note: required by a bound in `return_value`
+  --> $WORKSPACE/crates/env/src/api.rs
    |
-   |     <private::Seal<R> as ConstructorReturnType<Contract>>::Error: Encode,
-   |                                                                   ^^^^^^ required by this bound in `execute_constructor`
+   |     R: scale::Encode,
+   |        ^^^^^^^^^^^^^ required by this bound in `return_value`
 
 error[E0277]: the trait bound `contract::Error: TypeInfo` is not satisfied
- --> tests/ui/contract/fail/constructor-return-result-non-codec-error.rs:1:1
+ --> tests/ui/contract/fail/constructor-return-result-non-codec-error.rs:4:16
   |
-1 | #[ink::contract]
-  | ^^^^^^^^^^^^^^^^ the trait `TypeInfo` is not implemented for `contract::Error`
+4 |     pub struct Contract {}
+  |                ^^^^^^^^ the trait `TypeInfo` is not implemented for `contract::Error`
   |
   = help: the following other types implement trait `TypeInfo`:
             &T
@@ -36,6 +26,10 @@ error[E0277]: the trait bound `contract::Error: TypeInfo` is not satisfied
             (A, B, C, D)
             (A, B, C, D, E)
             (A, B, C, D, E, F)
-          and 64 others
-  = note: required for `Result<(), contract::Error>` to implement `ConstructorReturnSpec`
-  = note: this error originates in the attribute macro `ink::contract` (in Nightly builds, run with -Z macro-backtrace for more info)
+          and $N others
+  = note: required for `Result<(), contract::Error>` to implement `TypeInfo`
+note: required by a bound in `TypeSpec::with_name_str`
+ --> $WORKSPACE/crates/metadata/src/specs.rs
+  |
+  |         T: TypeInfo + 'static,
+  |            ^^^^^^^^ required by this bound in `TypeSpec::with_name_str`