Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/ide-assists/src/handlers/expand_rest_pattern.rs')
| -rw-r--r-- | crates/ide-assists/src/handlers/expand_rest_pattern.rs | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/crates/ide-assists/src/handlers/expand_rest_pattern.rs b/crates/ide-assists/src/handlers/expand_rest_pattern.rs new file mode 100644 index 0000000000..c79a982c38 --- /dev/null +++ b/crates/ide-assists/src/handlers/expand_rest_pattern.rs @@ -0,0 +1,508 @@ +use hir::{PathResolution, StructKind}; +use ide_db::syntax_helpers::suggest_name::NameGenerator; +use syntax::{ + ast::{self, make}, + match_ast, AstNode, ToSmolStr, +}; + +use crate::{AssistContext, AssistId, Assists}; + +pub(crate) fn expand_rest_pattern(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> { + let rest_pat = ctx.find_node_at_offset::<ast::RestPat>()?; + let parent = rest_pat.syntax().parent()?; + match_ast! { + match parent { + ast::RecordPatFieldList(it) => expand_record_rest_pattern(acc, ctx, it.syntax().parent().and_then(ast::RecordPat::cast)?, rest_pat), + ast::TupleStructPat(it) => expand_tuple_struct_rest_pattern(acc, ctx, it, rest_pat), + // FIXME + // ast::TuplePat(it) => (), + // FIXME + // ast::SlicePat(it) => (), + _ => return None, + } + } +} + +// Assist: expand_record_rest_pattern +// +// Fills fields by replacing rest pattern in record patterns. +// +// ``` +// struct Bar { y: Y, z: Z } +// +// fn foo(bar: Bar) { +// let Bar { ..$0 } = bar; +// } +// ``` +// -> +// ``` +// struct Bar { y: Y, z: Z } +// +// fn foo(bar: Bar) { +// let Bar { y, z } = bar; +// } +// ``` +fn expand_record_rest_pattern( + acc: &mut Assists, + ctx: &AssistContext<'_>, + record_pat: ast::RecordPat, + rest_pat: ast::RestPat, +) -> Option<()> { + let missing_fields = ctx.sema.record_pattern_missing_fields(&record_pat); + + if missing_fields.is_empty() { + cov_mark::hit!(no_missing_fields); + return None; + } + + let old_field_list = record_pat.record_pat_field_list()?; + let old_range = ctx.sema.original_range_opt(old_field_list.syntax())?; + if old_range.file_id != ctx.file_id() { + return None; + } + + let new_field_list = + make::record_pat_field_list(old_field_list.fields(), None).clone_for_update(); + for (f, _) in missing_fields.iter() { + let edition = ctx.sema.scope(record_pat.syntax())?.krate().edition(ctx.db()); + let field = make::record_pat_field_shorthand(make::name_ref( + &f.name(ctx.sema.db).display_no_db(edition).to_smolstr(), + )); + new_field_list.add_field(field.clone_for_update()); + } + + let target_range = rest_pat.syntax().text_range(); + acc.add( + AssistId("expand_record_rest_pattern", crate::AssistKind::RefactorRewrite), + "Fill struct fields", + target_range, + move |builder| builder.replace_ast(old_field_list, new_field_list), + ) +} +// Assist: expand_tuple_struct_rest_pattern +// +// Fills fields by replacing rest pattern in tuple struct patterns. +// +// ``` +// struct Bar(Y, Z); +// +// fn foo(bar: Bar) { +// let Bar(..$0) = bar; +// } +// ``` +// -> +// ``` +// struct Bar(Y, Z); +// +// fn foo(bar: Bar) { +// let Bar(_0, _1) = bar; +// } +// ``` +fn expand_tuple_struct_rest_pattern( + acc: &mut Assists, + ctx: &AssistContext<'_>, + pat: ast::TupleStructPat, + rest_pat: ast::RestPat, +) -> Option<()> { + let path = pat.path()?; + let fields = match ctx.sema.type_of_pat(&pat.clone().into())?.original.as_adt()? { + hir::Adt::Struct(s) if s.kind(ctx.sema.db) == StructKind::Tuple => s.fields(ctx.sema.db), + hir::Adt::Enum(_) => match ctx.sema.resolve_path(&path)? { + PathResolution::Def(hir::ModuleDef::Variant(v)) + if v.kind(ctx.sema.db) == StructKind::Tuple => + { + v.fields(ctx.sema.db) + } + _ => return None, + }, + _ => return None, + }; + + let rest_pat = rest_pat.into(); + let mut pats = pat.fields(); + let prefix_count = pats.by_ref().position(|p| p == rest_pat)?; + let suffix_count = pats.count(); + + if fields.len().saturating_sub(prefix_count).saturating_sub(suffix_count) == 0 { + cov_mark::hit!(no_missing_fields_tuple_struct); + return None; + } + + let old_range = ctx.sema.original_range_opt(pat.syntax())?; + if old_range.file_id != ctx.file_id() { + return None; + } + + let mut name_gen = NameGenerator::new_from_scope_locals(ctx.sema.scope(pat.syntax())); + let new_pat = make::tuple_struct_pat( + path, + pat.fields() + .take(prefix_count) + .chain(fields[prefix_count..fields.len() - suffix_count].iter().map(|f| { + make::ident_pat( + false, + false, + match name_gen.for_type(&f.ty(ctx.sema.db), ctx.sema.db, ctx.edition()) { + Some(name) => make::name(&name), + None => make::name(&format!("_{}", f.index())), + }, + ) + .into() + })) + .chain(pat.fields().skip(prefix_count + 1)), + ); + + let target_range = rest_pat.syntax().text_range(); + acc.add( + AssistId("expand_tuple_struct_rest_pattern", crate::AssistKind::RefactorRewrite), + "Fill tuple struct fields", + target_range, + move |builder| builder.replace_ast(pat, new_pat), + ) +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::tests::{check_assist, check_assist_not_applicable}; + + #[test] + fn fill_fields_enum_with_only_ellipsis() { + check_assist( + expand_rest_pattern, + r#" +enum Foo { + A(X), + B{y: Y, z: Z} +} + +fn bar(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B{ ..$0 } => true, + }; +} +"#, + r#" +enum Foo { + A(X), + B{y: Y, z: Z} +} + +fn bar(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B{ y, z } => true, + }; +} +"#, + ) + } + + #[test] + fn fill_fields_enum_with_fields() { + check_assist( + expand_rest_pattern, + r#" +enum Foo { + A(X), + B{y: Y, z: Z} +} + +fn bar(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B{ y, ..$0 } => true, + }; +} +"#, + r#" +enum Foo { + A(X), + B{y: Y, z: Z} +} + +fn bar(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B{ y, z } => true, + }; +} +"#, + ) + } + + #[test] + fn fill_fields_struct_with_only_ellipsis() { + check_assist( + expand_rest_pattern, + r#" +struct Bar { + y: Y, + z: Z, +} + +fn foo(bar: Bar) { + let Bar { ..$0 } = bar; +} +"#, + r#" +struct Bar { + y: Y, + z: Z, +} + +fn foo(bar: Bar) { + let Bar { y, z } = bar; +} +"#, + ); + check_assist( + expand_rest_pattern, + r#" +struct Y; +struct Z; +struct Bar(Y, Z) + +fn foo(bar: Bar) { + let Bar(..$0) = bar; +} +"#, + r#" +struct Y; +struct Z; +struct Bar(Y, Z) + +fn foo(bar: Bar) { + let Bar(y, z) = bar; +} +"#, + ) + } + + #[test] + fn fill_fields_struct_with_fields() { + check_assist( + expand_rest_pattern, + r#" +struct Bar { + y: Y, + z: Z, +} + +fn foo(bar: Bar) { + let Bar { y, ..$0 } = bar; +} +"#, + r#" +struct Bar { + y: Y, + z: Z, +} + +fn foo(bar: Bar) { + let Bar { y, z } = bar; +} +"#, + ); + check_assist( + expand_rest_pattern, + r#" +struct X; +struct Y; +struct Z; +struct Bar(X, Y, Z) + +fn foo(bar: Bar) { + let Bar(x, ..$0, z) = bar; +} +"#, + r#" +struct X; +struct Y; +struct Z; +struct Bar(X, Y, Z) + +fn foo(bar: Bar) { + let Bar(x, y, z) = bar; +} +"#, + ) + } + + #[test] + fn fill_fields_struct_generated_by_macro() { + check_assist( + expand_rest_pattern, + r#" +macro_rules! position { + ($t: ty) => { + struct Pos {x: $t, y: $t} + }; +} + +position!(usize); + +fn macro_call(pos: Pos) { + let Pos { ..$0 } = pos; +} +"#, + r#" +macro_rules! position { + ($t: ty) => { + struct Pos {x: $t, y: $t} + }; +} + +position!(usize); + +fn macro_call(pos: Pos) { + let Pos { x, y } = pos; +} +"#, + ); + } + + #[test] + fn fill_fields_enum_generated_by_macro() { + check_assist( + expand_rest_pattern, + r#" +macro_rules! enum_gen { + ($t: ty) => { + enum Foo { + A($t), + B{x: $t, y: $t}, + } + }; +} + +enum_gen!(usize); + +fn macro_call(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B{ ..$0 } => true, + } +} +"#, + r#" +macro_rules! enum_gen { + ($t: ty) => { + enum Foo { + A($t), + B{x: $t, y: $t}, + } + }; +} + +enum_gen!(usize); + +fn macro_call(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B{ x, y } => true, + } +} +"#, + ); + } + + #[test] + fn not_applicable_when_not_in_ellipsis() { + check_assist_not_applicable( + expand_rest_pattern, + r#" +enum Foo { + A(X), + B{y: Y, z: Z} +} + +fn bar(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B{..}$0 => true, + }; +} +"#, + ); + check_assist_not_applicable( + expand_rest_pattern, + r#" +enum Foo { + A(X), + B{y: Y, z: Z} +} + +fn bar(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B$0{..} => true, + }; +} +"#, + ); + check_assist_not_applicable( + expand_rest_pattern, + r#" +enum Foo { + A(X), + B{y: Y, z: Z} +} + +fn bar(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::$0B{..} => true, + }; +} +"#, + ); + } + + #[test] + fn not_applicable_when_no_missing_fields() { + // This is still possible even though it's meaningless + cov_mark::check!(no_missing_fields); + cov_mark::check!(no_missing_fields_tuple_struct); + check_assist_not_applicable( + expand_rest_pattern, + r#" +enum Foo { + A(X), + B{y: Y, z: Z} +} + +fn bar(foo: Foo) { + match foo { + Foo::A(_) => false, + Foo::B{y, z, ..$0} => true, + }; +} +"#, + ); + check_assist_not_applicable( + expand_rest_pattern, + r#" +struct Bar { + y: Y, + z: Z, +} + +fn foo(bar: Bar) { + let Bar { y, z, ..$0 } = bar; +} +"#, + ); + check_assist_not_applicable( + expand_rest_pattern, + r#" +struct Bar(Y, Z) + +fn foo(bar: Bar) { + let Bar(y, ..$0, z) = bar; +} +"#, + ); + } +} |