[rustc.git] / src / tools / rust-analyzer / crates / ide-completion / src / completions / expr.rs

//! Completion of names from the current scope in expression position.

use hir::ScopeDef;
use syntax::ast;

use crate::{
    completions::record::add_default_update,
    context::{ExprCtx, PathCompletionCtx, Qualified},
    CompletionContext, Completions,
};

pub(crate) fn complete_expr_path(
    acc: &mut Completions,
    ctx: &CompletionContext<'_>,
    path_ctx @ PathCompletionCtx { qualified, .. }: &PathCompletionCtx,
    expr_ctx: &ExprCtx,
) {
    let _p = profile::span("complete_expr_path");
    if !ctx.qualifier_ctx.none() {
        return;
    }

    let &ExprCtx {
        in_block_expr,
        in_loop_body,
        after_if_expr,
        in_condition,
        incomplete_let,
        ref ref_expr_parent,
        ref is_func_update,
        ref innermost_ret_ty,
        ref impl_,
        in_match_guard,
        ..
    } = expr_ctx;

    let wants_mut_token =
        ref_expr_parent.as_ref().map(|it| it.mut_token().is_none()).unwrap_or(false);

    let scope_def_applicable = |def| match def {
        ScopeDef::GenericParam(hir::GenericParam::LifetimeParam(_)) | ScopeDef::Label(_) => false,
        ScopeDef::ModuleDef(hir::ModuleDef::Macro(mac)) => mac.is_fn_like(ctx.db),
        _ => true,
    };

    let add_assoc_item = |acc: &mut Completions, item| match item {
        hir::AssocItem::Function(func) => acc.add_function(ctx, path_ctx, func, None),
        hir::AssocItem::Const(ct) => acc.add_const(ctx, ct),
        hir::AssocItem::TypeAlias(ty) => acc.add_type_alias(ctx, ty),
    };

    match qualified {
        Qualified::TypeAnchor { ty: None, trait_: None } => ctx
            .traits_in_scope()
            .iter()
            .flat_map(|&it| hir::Trait::from(it).items(ctx.sema.db))
            .for_each(|item| add_assoc_item(acc, item)),
        Qualified::TypeAnchor { trait_: Some(trait_), .. } => {
            trait_.items(ctx.sema.db).into_iter().for_each(|item| add_assoc_item(acc, item))
        }
        Qualified::TypeAnchor { ty: Some(ty), trait_: None } => {
            if let Some(hir::Adt::Enum(e)) = ty.as_adt() {
                cov_mark::hit!(completes_variant_through_alias);
                acc.add_enum_variants(ctx, path_ctx, e);
            }

            ctx.iterate_path_candidates(ty, |item| {
                add_assoc_item(acc, item);
            });

            // Iterate assoc types separately
            ty.iterate_assoc_items(ctx.db, ctx.krate, |item| {
                if let hir::AssocItem::TypeAlias(ty) = item {
                    acc.add_type_alias(ctx, ty)
                }
                None::<()>
            });
        }
        Qualified::With { resolution: None, .. } => {}
        Qualified::With { resolution: Some(resolution), .. } => {
            // Add associated types on type parameters and `Self`.
            ctx.scope.assoc_type_shorthand_candidates(resolution, |_, alias| {
                acc.add_type_alias(ctx, alias);
                None::<()>
            });
            match resolution {
                hir::PathResolution::Def(hir::ModuleDef::Module(module)) => {
                    let module_scope = module.scope(ctx.db, Some(ctx.module));
                    for (name, def) in module_scope {
                        if scope_def_applicable(def) {
                            acc.add_path_resolution(
                                ctx,
                                path_ctx,
                                name,
                                def,
                                ctx.doc_aliases_in_scope(def),
                            );
                        }
                    }
                }
                hir::PathResolution::Def(
                    def @ (hir::ModuleDef::Adt(_)
                    | hir::ModuleDef::TypeAlias(_)
                    | hir::ModuleDef::BuiltinType(_)),
                ) => {
                    let ty = match def {
                        hir::ModuleDef::Adt(adt) => adt.ty(ctx.db),
                        hir::ModuleDef::TypeAlias(a) => a.ty(ctx.db),
                        hir::ModuleDef::BuiltinType(builtin) => {
                            cov_mark::hit!(completes_primitive_assoc_const);
                            builtin.ty(ctx.db)
                        }
                        _ => return,
                    };

                    if let Some(hir::Adt::Enum(e)) = ty.as_adt() {
                        cov_mark::hit!(completes_variant_through_alias);
                        acc.add_enum_variants(ctx, path_ctx, e);
                    }

                    // XXX: For parity with Rust bug #22519, this does not complete Ty::AssocType.
                    // (where AssocType is defined on a trait, not an inherent impl)

                    ctx.iterate_path_candidates(&ty, |item| {
                        add_assoc_item(acc, item);
                    });

                    // Iterate assoc types separately
                    ty.iterate_assoc_items(ctx.db, ctx.krate, |item| {
                        if let hir::AssocItem::TypeAlias(ty) = item {
                            acc.add_type_alias(ctx, ty)
                        }
                        None::<()>
                    });
                }
                hir::PathResolution::Def(hir::ModuleDef::Trait(t)) => {
                    // Handles `Trait::assoc` as well as `<Ty as Trait>::assoc`.
                    for item in t.items(ctx.db) {
                        add_assoc_item(acc, item);
                    }
                }
                hir::PathResolution::TypeParam(_) | hir::PathResolution::SelfType(_) => {
                    let ty = match resolution {
                        hir::PathResolution::TypeParam(param) => param.ty(ctx.db),
                        hir::PathResolution::SelfType(impl_def) => impl_def.self_ty(ctx.db),
                        _ => return,
                    };

                    if let Some(hir::Adt::Enum(e)) = ty.as_adt() {
                        cov_mark::hit!(completes_variant_through_self);
                        acc.add_enum_variants(ctx, path_ctx, e);
                    }

                    ctx.iterate_path_candidates(&ty, |item| {
                        add_assoc_item(acc, item);
                    });
                }
                _ => (),
            }
        }
        Qualified::Absolute => acc.add_crate_roots(ctx, path_ctx),
        Qualified::No => {
            acc.add_nameref_keywords_with_colon(ctx);
            if let Some(adt) =
                ctx.expected_type.as_ref().and_then(|ty| ty.strip_references().as_adt())
            {
                let self_ty = (|| ctx.sema.to_def(impl_.as_ref()?)?.self_ty(ctx.db).as_adt())();
                let complete_self = self_ty == Some(adt);

                match adt {
                    hir::Adt::Struct(strukt) => {
                        let path = ctx
                            .module
                            .find_use_path(
                                ctx.db,
                                hir::ModuleDef::from(strukt),
                                ctx.config.prefer_no_std,
                            )
                            .filter(|it| it.len() > 1);

                        acc.add_struct_literal(ctx, path_ctx, strukt, path, None);

                        if complete_self {
                            acc.add_struct_literal(
                                ctx,
                                path_ctx,
                                strukt,
                                None,
                                Some(hir::known::SELF_TYPE),
                            );
                        }
                    }
                    hir::Adt::Union(un) => {
                        let path = ctx
                            .module
                            .find_use_path(
                                ctx.db,
                                hir::ModuleDef::from(un),
                                ctx.config.prefer_no_std,
                            )
                            .filter(|it| it.len() > 1);

                        acc.add_union_literal(ctx, un, path, None);
                        if complete_self {
                            acc.add_union_literal(ctx, un, None, Some(hir::known::SELF_TYPE));
                        }
                    }
                    hir::Adt::Enum(e) => {
                        super::enum_variants_with_paths(
                            acc,
                            ctx,
                            e,
                            impl_,
                            |acc, ctx, variant, path| {
                                acc.add_qualified_enum_variant(ctx, path_ctx, variant, path)
                            },
                        );
                    }
                }
            }
            ctx.process_all_names(&mut |name, def, doc_aliases| match def {
                ScopeDef::ModuleDef(hir::ModuleDef::Trait(t)) => {
                    let assocs = t.items_with_supertraits(ctx.db);
                    match &*assocs {
                        // traits with no assoc items are unusable as expressions since
                        // there is no associated item path that can be constructed with them
                        [] => (),
                        // FIXME: Render the assoc item with the trait qualified
                        &[_item] => acc.add_path_resolution(ctx, path_ctx, name, def, doc_aliases),
                        // FIXME: Append `::` to the thing here, since a trait on its own won't work
                        [..] => acc.add_path_resolution(ctx, path_ctx, name, def, doc_aliases),
                    }
                }
                _ if scope_def_applicable(def) => {
                    acc.add_path_resolution(ctx, path_ctx, name, def, doc_aliases)
                }
                _ => (),
            });

            match is_func_update {
                Some(record_expr) => {
                    let ty = ctx.sema.type_of_expr(&ast::Expr::RecordExpr(record_expr.clone()));

                    match ty.as_ref().and_then(|t| t.original.as_adt()) {
                        Some(hir::Adt::Union(_)) => (),
                        _ => {
                            cov_mark::hit!(functional_update);
                            let missing_fields =
                                ctx.sema.record_literal_missing_fields(record_expr);
                            if !missing_fields.is_empty() {
                                add_default_update(acc, ctx, ty);
                            }
                        }
                    };
                }
                None => {
                    let mut add_keyword = |kw, snippet| {
                        acc.add_keyword_snippet_expr(ctx, incomplete_let, kw, snippet)
                    };

                    if !in_block_expr {
                        add_keyword("unsafe", "unsafe {\n    $0\n}");
                    }
                    add_keyword("match", "match $1 {\n    $0\n}");
                    add_keyword("while", "while $1 {\n    $0\n}");
                    add_keyword("while let", "while let $1 = $2 {\n    $0\n}");
                    add_keyword("loop", "loop {\n    $0\n}");
                    if in_match_guard {
                        add_keyword("if", "if $0");
                    } else {
                        add_keyword("if", "if $1 {\n    $0\n}");
                    }
                    add_keyword("if let", "if let $1 = $2 {\n    $0\n}");
                    add_keyword("for", "for $1 in $2 {\n    $0\n}");
                    add_keyword("true", "true");
                    add_keyword("false", "false");

                    if in_condition || in_block_expr {
                        add_keyword("let", "let");
                    }

                    if after_if_expr {
                        add_keyword("else", "else {\n    $0\n}");
                        add_keyword("else if", "else if $1 {\n    $0\n}");
                    }

                    if wants_mut_token {
                        add_keyword("mut", "mut ");
                    }

                    if in_loop_body {
                        if in_block_expr {
                            add_keyword("continue", "continue;");
                            add_keyword("break", "break;");
                        } else {
                            add_keyword("continue", "continue");
                            add_keyword("break", "break");
                        }
                    }

                    if let Some(ret_ty) = innermost_ret_ty {
                        add_keyword(
                            "return",
                            match (ret_ty.is_unit(), in_block_expr) {
                                (true, true) => {
                                    cov_mark::hit!(return_unit_block);
                                    "return;"
                                }
                                (true, false) => {
                                    cov_mark::hit!(return_unit_no_block);
                                    "return"
                                }
                                (false, true) => {
                                    cov_mark::hit!(return_value_block);
                                    "return $0;"
                                }
                                (false, false) => {
                                    cov_mark::hit!(return_value_no_block);
                                    "return $0"
                                }
                            },
                        );
                    }
                }
            }
        }
    }
}
Commit	Line	Data
064997fb FG	1	//! Completion of names from the current scope in expression position.
	2
	3	use hir::ScopeDef;
f2b60f7d	4	use syntax::ast;
064997fb FG	5
064997fb FG	6	use crate::{
f2b60f7d	7	completions::record::add_default_update,
064997fb FG	8	context::{ExprCtx, PathCompletionCtx, Qualified},
	9	CompletionContext, Completions,
	10	};
	11
	12	pub(crate) fn complete_expr_path(
	13	acc: &mut Completions,
	14	ctx: &CompletionContext<'_>,
	15	path_ctx @ PathCompletionCtx { qualified, .. }: &PathCompletionCtx,
	16	expr_ctx: &ExprCtx,
	17	) {
	18	let _p = profile::span("complete_expr_path");
	19	if !ctx.qualifier_ctx.none() {
	20	return;
	21	}
	22
	23	let &ExprCtx {
	24	in_block_expr,
	25	in_loop_body,
	26	after_if_expr,
	27	in_condition,
	28	incomplete_let,
	29	ref ref_expr_parent,
	30	ref is_func_update,
	31	ref innermost_ret_ty,
	32	ref impl_,
	33	in_match_guard,
	34	..
	35	} = expr_ctx;
	36
	37	let wants_mut_token =
	38	ref_expr_parent.as_ref().map(\|it\| it.mut_token().is_none()).unwrap_or(false);
	39
	40	let scope_def_applicable = \|def\| match def {
	41	ScopeDef::GenericParam(hir::GenericParam::LifetimeParam(_)) \| ScopeDef::Label(_) => false,
	42	ScopeDef::ModuleDef(hir::ModuleDef::Macro(mac)) => mac.is_fn_like(ctx.db),
	43	_ => true,
	44	};
	45
	46	let add_assoc_item = \|acc: &mut Completions, item\| match item {
	47	hir::AssocItem::Function(func) => acc.add_function(ctx, path_ctx, func, None),
	48	hir::AssocItem::Const(ct) => acc.add_const(ctx, ct),
	49	hir::AssocItem::TypeAlias(ty) => acc.add_type_alias(ctx, ty),
	50	};
	51
	52	match qualified {
	53	Qualified::TypeAnchor { ty: None, trait_: None } => ctx
	54	.traits_in_scope()
	55	.iter()
	56	.flat_map(\|&it\| hir::Trait::from(it).items(ctx.sema.db))
	57	.for_each(\|item\| add_assoc_item(acc, item)),
	58	Qualified::TypeAnchor { trait_: Some(trait_), .. } => {
	59	trait_.items(ctx.sema.db).into_iter().for_each(\|item\| add_assoc_item(acc, item))
	60	}
	61	Qualified::TypeAnchor { ty: Some(ty), trait_: None } => {
	62	if let Some(hir::Adt::Enum(e)) = ty.as_adt() {
	63	cov_mark::hit!(completes_variant_through_alias);
	64	acc.add_enum_variants(ctx, path_ctx, e);
	65	}
	66
9c376795	67	ctx.iterate_path_candidates(ty, \|item\| {
064997fb FG	68	add_assoc_item(acc, item);
	69	});
	70
	71	// Iterate assoc types separately
	72	ty.iterate_assoc_items(ctx.db, ctx.krate, \|item\| {
	73	if let hir::AssocItem::TypeAlias(ty) = item {
	74	acc.add_type_alias(ctx, ty)
	75	}
	76	None::<()>
	77	});
	78	}
	79	Qualified::With { resolution: None, .. } => {}
	80	Qualified::With { resolution: Some(resolution), .. } => {
	81	// Add associated types on type parameters and `Self`.
	82	ctx.scope.assoc_type_shorthand_candidates(resolution, \|_, alias\| {
	83	acc.add_type_alias(ctx, alias);
	84	None::<()>
	85	});
	86	match resolution {
	87	hir::PathResolution::Def(hir::ModuleDef::Module(module)) => {
	88	let module_scope = module.scope(ctx.db, Some(ctx.module));
	89	for (name, def) in module_scope {
	90	if scope_def_applicable(def) {
fe692bf9 FG	91	acc.add_path_resolution(
	92	ctx,
	93	path_ctx,
	94	name,
	95	def,
	96	ctx.doc_aliases_in_scope(def),
	97	);
064997fb FG	98	}
	99	}
	100	}
	101	hir::PathResolution::Def(
	102	def @ (hir::ModuleDef::Adt(_)
	103	\| hir::ModuleDef::TypeAlias(_)
	104	\| hir::ModuleDef::BuiltinType(_)),
	105	) => {
	106	let ty = match def {
	107	hir::ModuleDef::Adt(adt) => adt.ty(ctx.db),
	108	hir::ModuleDef::TypeAlias(a) => a.ty(ctx.db),
	109	hir::ModuleDef::BuiltinType(builtin) => {
	110	cov_mark::hit!(completes_primitive_assoc_const);
	111	builtin.ty(ctx.db)
	112	}
	113	_ => return,
	114	};
	115
	116	if let Some(hir::Adt::Enum(e)) = ty.as_adt() {
	117	cov_mark::hit!(completes_variant_through_alias);
	118	acc.add_enum_variants(ctx, path_ctx, e);
	119	}
	120
	121	// XXX: For parity with Rust bug #22519, this does not complete Ty::AssocType.
	122	// (where AssocType is defined on a trait, not an inherent impl)
	123
	124	ctx.iterate_path_candidates(&ty, \|item\| {
	125	add_assoc_item(acc, item);
	126	});
	127
	128	// Iterate assoc types separately
	129	ty.iterate_assoc_items(ctx.db, ctx.krate, \|item\| {
	130	if let hir::AssocItem::TypeAlias(ty) = item {
	131	acc.add_type_alias(ctx, ty)
	132	}
	133	None::<()>
	134	});
	135	}
	136	hir::PathResolution::Def(hir::ModuleDef::Trait(t)) => {
	137	// Handles `Trait::assoc` as well as `<Ty as Trait>::assoc`.
	138	for item in t.items(ctx.db) {
	139	add_assoc_item(acc, item);
	140	}
	141	}
	142	hir::PathResolution::TypeParam(_) \| hir::PathResolution::SelfType(_) => {
	143	let ty = match resolution {
	144	hir::PathResolution::TypeParam(param) => param.ty(ctx.db),
	145	hir::PathResolution::SelfType(impl_def) => impl_def.self_ty(ctx.db),
	146	_ => return,
	147	};
	148
	149	if let Some(hir::Adt::Enum(e)) = ty.as_adt() {
	150	cov_mark::hit!(completes_variant_through_self);
	151	acc.add_enum_variants(ctx, path_ctx, e);
	152	}
	153
	154	ctx.iterate_path_candidates(&ty, \|item\| {
	155	add_assoc_item(acc, item);
	156	});
	157	}
	158	_ => (),
	159	}
	160	}
	161	Qualified::Absolute => acc.add_crate_roots(ctx, path_ctx),
162	Qualified::No => {
163	acc.add_nameref_keywords_with_colon(ctx);
164	if let Some(adt) =
165	ctx.expected_type.as_ref().and_then(\|ty\| ty.strip_references().as_adt())
166	{
167	let self_ty = (\|\| ctx.sema.to_def(impl_.as_ref()?)?.self_ty(ctx.db).as_adt())();
168	let complete_self = self_ty == Some(adt);
169
170	match adt {
171	hir::Adt::Struct(strukt) => {
172	let path = ctx
173	.module
2b03887a FG	174	.find_use_path(
	175	ctx.db,
	176	hir::ModuleDef::from(strukt),
	177	ctx.config.prefer_no_std,
	178	)
064997fb FG	179	.filter(\|it\| it.len() > 1);
	180
	181	acc.add_struct_literal(ctx, path_ctx, strukt, path, None);
	182
	183	if complete_self {
	184	acc.add_struct_literal(
	185	ctx,
	186	path_ctx,
	187	strukt,
	188	None,
	189	Some(hir::known::SELF_TYPE),
	190	);
	191	}
	192	}
	193	hir::Adt::Union(un) => {
	194	let path = ctx
	195	.module
2b03887a FG	196	.find_use_path(
	197	ctx.db,
	198	hir::ModuleDef::from(un),
	199	ctx.config.prefer_no_std,
	200	)
064997fb FG	201	.filter(\|it\| it.len() > 1);
	202
	203	acc.add_union_literal(ctx, un, path, None);
	204	if complete_self {
	205	acc.add_union_literal(ctx, un, None, Some(hir::known::SELF_TYPE));
	206	}
	207	}
	208	hir::Adt::Enum(e) => {
	209	super::enum_variants_with_paths(
	210	acc,
	211	ctx,
	212	e,
	213	impl_,
	214	\|acc, ctx, variant, path\| {
	215	acc.add_qualified_enum_variant(ctx, path_ctx, variant, path)
	216	},
	217	);
	218	}
	219	}
	220	}
fe692bf9	221	ctx.process_all_names(&mut \|name, def, doc_aliases\| match def {
064997fb FG	222	ScopeDef::ModuleDef(hir::ModuleDef::Trait(t)) => {
	223	let assocs = t.items_with_supertraits(ctx.db);
	224	match &*assocs {
	225	// traits with no assoc items are unusable as expressions since
	226	// there is no associated item path that can be constructed with them
	227	[] => (),
	228	// FIXME: Render the assoc item with the trait qualified
fe692bf9	229	&[_item] => acc.add_path_resolution(ctx, path_ctx, name, def, doc_aliases),
064997fb	230	// FIXME: Append `::` to the thing here, since a trait on its own won't work
fe692bf9	231	[..] => acc.add_path_resolution(ctx, path_ctx, name, def, doc_aliases),
064997fb FG	232	}
064997fb FG	233	}
fe692bf9 FG	234	_ if scope_def_applicable(def) => {
	235	acc.add_path_resolution(ctx, path_ctx, name, def, doc_aliases)
	236	}
064997fb FG	237	_ => (),
	238	});
	239
f2b60f7d FG	240	match is_func_update {
	241	Some(record_expr) => {
	242	let ty = ctx.sema.type_of_expr(&ast::Expr::RecordExpr(record_expr.clone()));
064997fb	243
f2b60f7d FG	244	match ty.as_ref().and_then(\|t\| t.original.as_adt()) {
	245	Some(hir::Adt::Union(_)) => (),
	246	_ => {
	247	cov_mark::hit!(functional_update);
	248	let missing_fields =
	249	ctx.sema.record_literal_missing_fields(record_expr);
	250	if !missing_fields.is_empty() {
	251	add_default_update(acc, ctx, ty);
	252	}
	253	}
	254	};
064997fb	255	}
f2b60f7d FG	256	None => {
	257	let mut add_keyword = \|kw, snippet\| {
	258	acc.add_keyword_snippet_expr(ctx, incomplete_let, kw, snippet)
	259	};
064997fb	260
f2b60f7d FG	261	if !in_block_expr {
	262	add_keyword("unsafe", "unsafe {\n $0\n}");
	263	}
	264	add_keyword("match", "match $1 {\n $0\n}");
	265	add_keyword("while", "while $1 {\n $0\n}");
	266	add_keyword("while let", "while let $1 = $2 {\n $0\n}");
	267	add_keyword("loop", "loop {\n $0\n}");
	268	if in_match_guard {
	269	add_keyword("if", "if $0");
	270	} else {
	271	add_keyword("if", "if $1 {\n $0\n}");
	272	}
	273	add_keyword("if let", "if let $1 = $2 {\n $0\n}");
	274	add_keyword("for", "for $1 in $2 {\n $0\n}");
	275	add_keyword("true", "true");
	276	add_keyword("false", "false");
064997fb	277
f2b60f7d FG	278	if in_condition \|\| in_block_expr {
	279	add_keyword("let", "let");
	280	}
064997fb	281
f2b60f7d FG	282	if after_if_expr {
	283	add_keyword("else", "else {\n $0\n}");
	284	add_keyword("else if", "else if $1 {\n $0\n}");
	285	}
064997fb	286
f2b60f7d FG	287	if wants_mut_token {
	288	add_keyword("mut", "mut ");
	289	}
	290
	291	if in_loop_body {
	292	if in_block_expr {
	293	add_keyword("continue", "continue;");
	294	add_keyword("break", "break;");
	295	} else {
	296	add_keyword("continue", "continue");
	297	add_keyword("break", "break");
	298	}
064997fb	299	}
064997fb	300
f2b60f7d FG	301	if let Some(ret_ty) = innermost_ret_ty {
	302	add_keyword(
	303	"return",
	304	match (ret_ty.is_unit(), in_block_expr) {
	305	(true, true) => {
	306	cov_mark::hit!(return_unit_block);
	307	"return;"
	308	}
	309	(true, false) => {
	310	cov_mark::hit!(return_unit_no_block);
	311	"return"
	312	}
	313	(false, true) => {
	314	cov_mark::hit!(return_value_block);
	315	"return $0;"
	316	}
	317	(false, false) => {
	318	cov_mark::hit!(return_value_no_block);
	319	"return $0"
	320	}
	321	},
	322	);
	323	}
064997fb FG	324	}
	325	}
	326	}
	327	}
	328	}