Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/ide/src/inlay_hints/bind_pat.rs')
| -rw-r--r-- | crates/ide/src/inlay_hints/bind_pat.rs | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/crates/ide/src/inlay_hints/bind_pat.rs b/crates/ide/src/inlay_hints/bind_pat.rs new file mode 100644 index 0000000000..68beb8fc35 --- /dev/null +++ b/crates/ide/src/inlay_hints/bind_pat.rs @@ -0,0 +1,187 @@ +use hir::{HirDisplay, Semantics, TypeInfo}; +use ide_db::{base_db::FileId, famous_defs::FamousDefs, RootDatabase}; + +use itertools::Itertools; +use syntax::{ + ast::{self, AstNode, HasName}, + match_ast, +}; + +use crate::{ + inlay_hints::{closure_has_block_body, hint_iterator}, + InlayHint, InlayHintsConfig, InlayKind, InlayTooltip, +}; + +pub(super) fn hints( + acc: &mut Vec<InlayHint>, + sema: &Semantics<'_, RootDatabase>, + config: &InlayHintsConfig, + file_id: FileId, + pat: &ast::IdentPat, +) -> Option<()> { + if !config.type_hints { + return None; + } + + let descended = sema.descend_node_into_attributes(pat.clone()).pop(); + let desc_pat = descended.as_ref().unwrap_or(pat); + let ty = sema.type_of_pat(&desc_pat.clone().into())?.original; + + if should_not_display_type_hint(sema, config, pat, &ty) { + return None; + } + + let krate = sema.scope(desc_pat.syntax())?.krate(); + let famous_defs = FamousDefs(sema, krate); + let label = hint_iterator(sema, &famous_defs, config, &ty); + + let label = match label { + Some(label) => label, + None => { + let ty_name = ty.display_truncated(sema.db, config.max_length).to_string(); + if config.hide_named_constructor_hints + && is_named_constructor(sema, pat, &ty_name).is_some() + { + return None; + } + ty_name + } + }; + + acc.push(InlayHint { + range: match pat.name() { + Some(name) => name.syntax().text_range(), + None => pat.syntax().text_range(), + }, + kind: InlayKind::TypeHint, + label: label.into(), + tooltip: pat + .name() + .map(|it| it.syntax().text_range()) + .map(|it| InlayTooltip::HoverRanged(file_id, it)), + }); + + Some(()) +} + +fn should_not_display_type_hint( + sema: &Semantics<'_, RootDatabase>, + config: &InlayHintsConfig, + bind_pat: &ast::IdentPat, + pat_ty: &hir::Type, +) -> bool { + let db = sema.db; + + if pat_ty.is_unknown() { + return true; + } + + if let Some(hir::Adt::Struct(s)) = pat_ty.as_adt() { + if s.fields(db).is_empty() && s.name(db).to_smol_str() == bind_pat.to_string() { + return true; + } + } + + if config.hide_closure_initialization_hints { + if let Some(parent) = bind_pat.syntax().parent() { + if let Some(it) = ast::LetStmt::cast(parent.clone()) { + if let Some(ast::Expr::ClosureExpr(closure)) = it.initializer() { + if closure_has_block_body(&closure) { + return true; + } + } + } + } + } + + for node in bind_pat.syntax().ancestors() { + match_ast! { + match node { + ast::LetStmt(it) => return it.ty().is_some(), + // FIXME: We might wanna show type hints in parameters for non-top level patterns as well + ast::Param(it) => return it.ty().is_some(), + ast::MatchArm(_) => return pat_is_enum_variant(db, bind_pat, pat_ty), + ast::LetExpr(_) => return pat_is_enum_variant(db, bind_pat, pat_ty), + ast::IfExpr(_) => return false, + ast::WhileExpr(_) => return false, + ast::ForExpr(it) => { + // We *should* display hint only if user provided "in {expr}" and we know the type of expr (and it's not unit). + // Type of expr should be iterable. + return it.in_token().is_none() || + it.iterable() + .and_then(|iterable_expr| sema.type_of_expr(&iterable_expr)) + .map(TypeInfo::original) + .map_or(true, |iterable_ty| iterable_ty.is_unknown() || iterable_ty.is_unit()) + }, + _ => (), + } + } + } + false +} + +fn is_named_constructor( + sema: &Semantics<'_, RootDatabase>, + pat: &ast::IdentPat, + ty_name: &str, +) -> Option<()> { + let let_node = pat.syntax().parent()?; + let expr = match_ast! { + match let_node { + ast::LetStmt(it) => it.initializer(), + ast::LetExpr(it) => it.expr(), + _ => None, + } + }?; + + let expr = sema.descend_node_into_attributes(expr.clone()).pop().unwrap_or(expr); + // unwrap postfix expressions + let expr = match expr { + ast::Expr::TryExpr(it) => it.expr(), + ast::Expr::AwaitExpr(it) => it.expr(), + expr => Some(expr), + }?; + let expr = match expr { + ast::Expr::CallExpr(call) => match call.expr()? { + ast::Expr::PathExpr(path) => path, + _ => return None, + }, + ast::Expr::PathExpr(path) => path, + _ => return None, + }; + let path = expr.path()?; + + let callable = sema.type_of_expr(&ast::Expr::PathExpr(expr))?.original.as_callable(sema.db); + let callable_kind = callable.map(|it| it.kind()); + let qual_seg = match callable_kind { + Some(hir::CallableKind::Function(_) | hir::CallableKind::TupleEnumVariant(_)) => { + path.qualifier()?.segment() + } + _ => path.segment(), + }?; + + let ctor_name = match qual_seg.kind()? { + ast::PathSegmentKind::Name(name_ref) => { + match qual_seg.generic_arg_list().map(|it| it.generic_args()) { + Some(generics) => format!("{}<{}>", name_ref, generics.format(", ")), + None => name_ref.to_string(), + } + } + ast::PathSegmentKind::Type { type_ref: Some(ty), trait_ref: None } => ty.to_string(), + _ => return None, + }; + (ctor_name == ty_name).then(|| ()) +} + +fn pat_is_enum_variant(db: &RootDatabase, bind_pat: &ast::IdentPat, pat_ty: &hir::Type) -> bool { + if let Some(hir::Adt::Enum(enum_data)) = pat_ty.as_adt() { + let pat_text = bind_pat.to_string(); + enum_data + .variants(db) + .into_iter() + .map(|variant| variant.name(db).to_smol_str()) + .any(|enum_name| enum_name == pat_text) + } else { + false + } +} |