Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/ide-assists/src/handlers/generate_trait_from_impl.rs')
| -rw-r--r-- | crates/ide-assists/src/handlers/generate_trait_from_impl.rs | 429 |
1 files changed, 429 insertions, 0 deletions
diff --git a/crates/ide-assists/src/handlers/generate_trait_from_impl.rs b/crates/ide-assists/src/handlers/generate_trait_from_impl.rs new file mode 100644 index 0000000000..0f67380d12 --- /dev/null +++ b/crates/ide-assists/src/handlers/generate_trait_from_impl.rs @@ -0,0 +1,429 @@ +use crate::assist_context::{AssistContext, Assists}; +use ide_db::assists::AssistId; +use syntax::{ + ast::{self, edit::IndentLevel, make, HasGenericParams, HasVisibility}, + ted, AstNode, SyntaxKind, +}; + +// NOTES : +// We generate erroneous code if a function is declared const (E0379) +// This is left to the user to correct as our only option is to remove the +// function completely which we should not be doing. + +// Assist: generate_trait_from_impl +// +// Generate trait for an already defined inherent impl and convert impl to a trait impl. +// +// ``` +// struct Foo<const N: usize>([i32; N]); +// +// macro_rules! const_maker { +// ($t:ty, $v:tt) => { +// const CONST: $t = $v; +// }; +// } +// +// impl<const N: usize> Fo$0o<N> { +// // Used as an associated constant. +// const CONST_ASSOC: usize = N * 4; +// +// fn create() -> Option<()> { +// Some(()) +// } +// +// const_maker! {i32, 7} +// } +// ``` +// -> +// ``` +// struct Foo<const N: usize>([i32; N]); +// +// macro_rules! const_maker { +// ($t:ty, $v:tt) => { +// const CONST: $t = $v; +// }; +// } +// +// trait ${0:TraitName}<const N: usize> { +// // Used as an associated constant. +// const CONST_ASSOC: usize = N * 4; +// +// fn create() -> Option<()>; +// +// const_maker! {i32, 7} +// } +// +// impl<const N: usize> ${0:TraitName}<N> for Foo<N> { +// // Used as an associated constant. +// const CONST_ASSOC: usize = N * 4; +// +// fn create() -> Option<()> { +// Some(()) +// } +// +// const_maker! {i32, 7} +// } +// ``` +pub(crate) fn generate_trait_from_impl(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> { + // Get AST Node + let impl_ast = ctx.find_node_at_offset::<ast::Impl>()?; + + // Check if cursor is to the left of assoc item list's L_CURLY. + // if no L_CURLY then return. + let l_curly = impl_ast.assoc_item_list()?.l_curly_token()?; + + let cursor_offset = ctx.offset(); + let l_curly_offset = l_curly.text_range(); + if cursor_offset >= l_curly_offset.start() { + return None; + } + + // If impl is not inherent then we don't really need to go any further. + if impl_ast.for_token().is_some() { + return None; + } + + let assoc_items = impl_ast.assoc_item_list()?; + let first_element = assoc_items.assoc_items().next(); + if first_element.is_none() { + // No reason for an assist. + return None; + } + + let impl_name = impl_ast.self_ty()?; + + acc.add( + AssistId("generate_trait_from_impl", ide_db::assists::AssistKind::Generate), + "Generate trait from impl", + impl_ast.syntax().text_range(), + |builder| { + let trait_items = assoc_items.clone_for_update(); + let impl_items = assoc_items.clone_for_update(); + + trait_items.assoc_items().for_each(|item| { + strip_body(&item); + remove_items_visibility(&item); + }); + + impl_items.assoc_items().for_each(|item| { + remove_items_visibility(&item); + }); + + let trait_ast = make::trait_( + false, + "NewTrait", + impl_ast.generic_param_list(), + impl_ast.where_clause(), + trait_items, + ); + + // Change `impl Foo` to `impl NewTrait for Foo` + let arg_list = if let Some(genpars) = impl_ast.generic_param_list() { + genpars.to_generic_args().to_string() + } else { + "".to_string() + }; + + if let Some(snippet_cap) = ctx.config.snippet_cap { + builder.replace_snippet( + snippet_cap, + impl_name.syntax().text_range(), + format!("${{0:TraitName}}{} for {}", arg_list, impl_name.to_string()), + ); + + // Insert trait before TraitImpl + builder.insert_snippet( + snippet_cap, + impl_ast.syntax().text_range().start(), + format!( + "{}\n\n{}", + trait_ast.to_string().replace("NewTrait", "${0:TraitName}"), + IndentLevel::from_node(impl_ast.syntax()) + ), + ); + } else { + builder.replace( + impl_name.syntax().text_range(), + format!("NewTrait{} for {}", arg_list, impl_name.to_string()), + ); + + // Insert trait before TraitImpl + builder.insert( + impl_ast.syntax().text_range().start(), + format!( + "{}\n\n{}", + trait_ast.to_string(), + IndentLevel::from_node(impl_ast.syntax()) + ), + ); + } + + builder.replace(assoc_items.syntax().text_range(), impl_items.to_string()); + }, + ); + + Some(()) +} + +/// `E0449` Trait items always share the visibility of their trait +fn remove_items_visibility(item: &ast::AssocItem) { + match item { + ast::AssocItem::Const(c) => { + if let Some(vis) = c.visibility() { + ted::remove(vis.syntax()); + } + } + ast::AssocItem::Fn(f) => { + if let Some(vis) = f.visibility() { + ted::remove(vis.syntax()); + } + } + ast::AssocItem::TypeAlias(t) => { + if let Some(vis) = t.visibility() { + ted::remove(vis.syntax()); + } + } + _ => (), + } +} + +fn strip_body(item: &ast::AssocItem) { + match item { + ast::AssocItem::Fn(f) => { + if let Some(body) = f.body() { + // In constrast to function bodies, we want to see no ws before a semicolon. + // So let's remove them if we see any. + if let Some(prev) = body.syntax().prev_sibling_or_token() { + if prev.kind() == SyntaxKind::WHITESPACE { + ted::remove(prev); + } + } + + ted::replace(body.syntax(), make::tokens::semicolon()); + } + } + _ => (), + }; +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::tests::{check_assist, check_assist_no_snippet_cap, check_assist_not_applicable}; + + #[test] + fn test_trigger_when_cursor_on_header() { + check_assist_not_applicable( + generate_trait_from_impl, + r#" +struct Foo(f64); + +impl Foo { $0 + fn add(&mut self, x: f64) { + self.0 += x; + } +}"#, + ); + } + + #[test] + fn test_assoc_item_fn() { + check_assist_no_snippet_cap( + generate_trait_from_impl, + r#" +struct Foo(f64); + +impl F$0oo { + fn add(&mut self, x: f64) { + self.0 += x; + } +}"#, + r#" +struct Foo(f64); + +trait NewTrait { + fn add(&mut self, x: f64); +} + +impl NewTrait for Foo { + fn add(&mut self, x: f64) { + self.0 += x; + } +}"#, + ) + } + + #[test] + fn test_assoc_item_macro() { + check_assist_no_snippet_cap( + generate_trait_from_impl, + r#" +struct Foo; + +macro_rules! const_maker { + ($t:ty, $v:tt) => { + const CONST: $t = $v; + }; +} + +impl F$0oo { + const_maker! {i32, 7} +}"#, + r#" +struct Foo; + +macro_rules! const_maker { + ($t:ty, $v:tt) => { + const CONST: $t = $v; + }; +} + +trait NewTrait { + const_maker! {i32, 7} +} + +impl NewTrait for Foo { + const_maker! {i32, 7} +}"#, + ) + } + + #[test] + fn test_assoc_item_const() { + check_assist_no_snippet_cap( + generate_trait_from_impl, + r#" +struct Foo; + +impl F$0oo { + const ABC: i32 = 3; +}"#, + r#" +struct Foo; + +trait NewTrait { + const ABC: i32 = 3; +} + +impl NewTrait for Foo { + const ABC: i32 = 3; +}"#, + ) + } + + #[test] + fn test_impl_with_generics() { + check_assist_no_snippet_cap( + generate_trait_from_impl, + r#" +struct Foo<const N: usize>([i32; N]); + +impl<const N: usize> F$0oo<N> { + // Used as an associated constant. + const CONST: usize = N * 4; +} + "#, + r#" +struct Foo<const N: usize>([i32; N]); + +trait NewTrait<const N: usize> { + // Used as an associated constant. + const CONST: usize = N * 4; +} + +impl<const N: usize> NewTrait<N> for Foo<N> { + // Used as an associated constant. + const CONST: usize = N * 4; +} + "#, + ) + } + + #[test] + fn test_trait_items_should_not_have_vis() { + check_assist_no_snippet_cap( + generate_trait_from_impl, + r#" +struct Foo; + +impl F$0oo { + pub fn a_func() -> Option<()> { + Some(()) + } +}"#, + r#" +struct Foo; + +trait NewTrait { + fn a_func() -> Option<()>; +} + +impl NewTrait for Foo { + fn a_func() -> Option<()> { + Some(()) + } +}"#, + ) + } + + #[test] + fn test_empty_inherent_impl() { + check_assist_not_applicable( + generate_trait_from_impl, + r#" +impl Emp$0tyImpl{} +"#, + ) + } + + #[test] + fn test_not_top_level_impl() { + check_assist_no_snippet_cap( + generate_trait_from_impl, + r#" +mod a { + impl S$0 { + fn foo() {} + } +}"#, + r#" +mod a { + trait NewTrait { + fn foo(); + } + + impl NewTrait for S { + fn foo() {} + } +}"#, + ) + } + + #[test] + fn test_snippet_cap_is_some() { + check_assist( + generate_trait_from_impl, + r#" +struct Foo<const N: usize>([i32; N]); + +impl<const N: usize> F$0oo<N> { + // Used as an associated constant. + const CONST: usize = N * 4; +} + "#, + r#" +struct Foo<const N: usize>([i32; N]); + +trait ${0:TraitName}<const N: usize> { + // Used as an associated constant. + const CONST: usize = N * 4; +} + +impl<const N: usize> ${0:TraitName}<N> for Foo<N> { + // Used as an associated constant. + const CONST: usize = N * 4; +} + "#, + ) + } +} |