rust-analyzer

diff --git a/crates/ide-assists/src/handlers/generate_from_impl_for_enum.rs b/crates/ide-assists/src/handlers/generate_from_impl_for_enum.rs
index 7c81d2c6a6..742f1f78c2 100644
--- a/crates/ide-assists/src/handlers/generate_from_impl_for_enum.rs
+++ b/crates/ide-assists/src/handlers/generate_from_impl_for_enum.rs

@@ -1,7 +1,9 @@

use ide_db::{famous_defs::FamousDefs, RootDatabase};

use syntax::ast::{self, AstNode, HasName};

-use crate::{utils::generate_trait_impl_text, AssistContext, AssistId, AssistKind, Assists};

+use crate::{

+ utils::generate_trait_impl_text_intransitive, AssistContext, AssistId, AssistKind, Assists,

+};

// Assist: generate_from_impl_for_enum

@@ -70,7 +72,7 @@ pub(crate) fn generate_from_impl_for_enum(

}}"#

)

};

- let from_impl = generate_trait_impl_text(&enum_, &from_trait, &impl_code);

+ let from_impl = generate_trait_impl_text_intransitive(&enum_, &from_trait, &impl_code);

edit.insert(start_offset, from_impl);

)

diff --git a/crates/ide-assists/src/handlers/generate_impl.rs b/crates/ide-assists/src/handlers/generate_impl.rs
index 690c97e26d..9ad14a819d 100644
--- a/crates/ide-assists/src/handlers/generate_impl.rs
+++ b/crates/ide-assists/src/handlers/generate_impl.rs

@@ -1,7 +1,7 @@

use syntax::ast::{self, AstNode, HasName};

use crate::{

- utils::{generate_impl_text, generate_trait_impl_text},

+ utils::{generate_impl_text, generate_trait_impl_text_intransitive},

AssistContext, AssistId, AssistKind, Assists,

};

@@ -89,11 +89,11 @@ pub(crate) fn generate_trait_impl(acc: &mut Assists, ctx: &AssistContext<'_>) ->

let start_offset = nominal.syntax().text_range().end();

match ctx.config.snippet_cap {

Some(cap) => {

- let snippet = generate_trait_impl_text(&nominal, "$0", "");

+ let snippet = generate_trait_impl_text_intransitive(&nominal, "$0", "");

edit.insert_snippet(cap, start_offset, snippet);

}

None => {

- let text = generate_trait_impl_text(&nominal, "", "");

+ let text = generate_trait_impl_text_intransitive(&nominal, "", "");

edit.insert(start_offset, text);

}

diff --git a/crates/ide-assists/src/utils.rs b/crates/ide-assists/src/utils.rs
index 2dcf56501d..f9812741e5 100644
--- a/crates/ide-assists/src/utils.rs
+++ b/crates/ide-assists/src/utils.rs

@@ -5,7 +5,6 @@ use std::ops;

pub(crate) use gen_trait_fn_body::gen_trait_fn_body;

use hir::{db::HirDatabase, HirDisplay, Semantics};

use ide_db::{famous_defs::FamousDefs, path_transform::PathTransform, RootDatabase, SnippetCap};

-use itertools::Itertools;

use stdx::format_to;

use syntax::{

ast::{

@@ -435,52 +434,67 @@ pub(crate) fn find_impl_block_end(impl_def: ast::Impl, buf: &mut String) -> Opti

Some(end)

}

-// Generates the surrounding `impl Type { <code> }` including type and lifetime

-// parameters

+/// Generates the surrounding `impl Type { <code> }` including type and lifetime

+/// parameters.

pub(crate) fn generate_impl_text(adt: &ast::Adt, code: &str) -> String {

- generate_impl_text_inner(adt, None, code)

+ generate_impl_text_inner(adt, None, true, code)

}

-// Generates the surrounding `impl <trait> for Type { <code> }` including type

-// and lifetime parameters

+/// Generates the surrounding `impl <trait> for Type { <code> }` including type

+/// and lifetime parameters, with `<trait>` appended to `impl`'s generic parameters' bounds.

+///

+/// This is useful for traits like `PartialEq`, since `impl<T> PartialEq for U<T>` often requires `T: PartialEq`.

pub(crate) fn generate_trait_impl_text(adt: &ast::Adt, trait_text: &str, code: &str) -> String {

- generate_impl_text_inner(adt, Some(trait_text), code)

+ generate_impl_text_inner(adt, Some(trait_text), true, code)

+/// Generates the surrounding `impl <trait> for Type { <code> }` including type

+/// and lifetime parameters, with `impl`'s generic parameters' bounds kept as-is.

+///

+/// This is useful for traits like `From<T>`, since `impl<T> From<T> for U<T>` doesn't require `T: From<T>`.

+pub(crate) fn generate_trait_impl_text_intransitive(

+ adt: &ast::Adt,

+ trait_text: &str,

+ code: &str,

+) -> String {

+ generate_impl_text_inner(adt, Some(trait_text), false, code)

}

-fn generate_impl_text_inner(adt: &ast::Adt, trait_text: Option<&str>, code: &str) -> String {

+fn generate_impl_text_inner(

+ adt: &ast::Adt,

+ trait_text: Option<&str>,

+ trait_is_transitive: bool,

+ code: &str,

+) -> String {

// Ensure lifetime params are before type & const params

let generic_params = adt.generic_param_list().map(|generic_params| {

let lifetime_params =

generic_params.lifetime_params().map(ast::GenericParam::LifetimeParam);

- let ty_or_const_params = generic_params.type_or_const_params().filter_map(|param| {

+ let ty_or_const_params = generic_params.type_or_const_params().map(|param| {

match param {

ast::TypeOrConstParam::Type(param) => {

let param = param.clone_for_update();

// remove defaults since they can't be specified in impls

param.remove_default();

- let mut bounds = param

- .type_bound_list()

- .map_or_else(Vec::new, |it| it.bounds().collect_vec());

- // `{ty_param}: {trait_text}`

+ let mut bounds =

+ param.type_bound_list().map_or_else(Vec::new, |it| it.bounds().collect());

if let Some(trait_) = trait_text {

- // Defense against the following cases:

- // - The trait is undetermined, e.g. `$0`.

- // - The trait is a `From`, e.g. `From<T>`.

- if !trait_.starts_with('$')

- && !matches!(trait_.split_once('<'), Some((left, _right)) if left.trim() == "From")

- {

+ // Add the current trait to `bounds` if the trait is transitive,

+ // meaning `impl<T> Trait for U<T>` requires `T: Trait`.

+ if trait_is_transitive {

bounds.push(make::type_bound(trait_));

}

};

+ // `{ty_param}: {bounds}`

let param =

make::type_param(param.name().unwrap(), make::type_bound_list(bounds));

- Some(ast::GenericParam::TypeParam(param))

+ ast::GenericParam::TypeParam(param)

}

ast::TypeOrConstParam::Const(param) => {

let param = param.clone_for_update();

// remove defaults since they can't be specified in impls

param.remove_default();

- Some(ast::GenericParam::ConstParam(param))

+ ast::GenericParam::ConstParam(param)

}

});

diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index 11822361f4..686bb40ecd 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs

@@ -734,8 +734,8 @@ pub fn type_bound_list(

}

pub fn type_param(name: ast::Name, bounds: Option<ast::TypeBoundList>) -> ast::TypeParam {

- let bound = bounds.map_or_else(String::new, |it| format!(": {it}"));

- ast_from_text(&format!("fn f<{name}{bound}>() {{ }}"))

+ let bounds = bounds.map_or_else(String::new, |it| format!(": {it}"));

+ ast_from_text(&format!("fn f<{name}{bounds}>() {{ }}"))

}

pub fn lifetime_param(lifetime: ast::Lifetime) -> ast::LifetimeParam {