rust/crates/ra_ide/src/hover.rs
2020-02-27 00:12:26 +08:00

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//! FIXME: write short doc here
use hir::{Adt, HasSource, HirDisplay, Semantics};
use ra_ide_db::{
defs::{classify_name, NameDefinition},
RootDatabase,
};
use ra_syntax::{
algo::find_covering_element,
ast::{self, DocCommentsOwner},
match_ast, AstNode,
SyntaxKind::*,
SyntaxToken, TokenAtOffset,
};
use crate::{
display::{macro_label, rust_code_markup, rust_code_markup_with_doc, ShortLabel},
references::classify_name_ref,
FilePosition, FileRange, RangeInfo,
};
/// Contains the results when hovering over an item
#[derive(Debug, Clone)]
pub struct HoverResult {
results: Vec<String>,
exact: bool,
}
impl Default for HoverResult {
fn default() -> Self {
HoverResult::new()
}
}
impl HoverResult {
pub fn new() -> HoverResult {
HoverResult {
results: Vec::new(),
// We assume exact by default
exact: true,
}
}
pub fn extend(&mut self, item: Option<String>) {
self.results.extend(item);
}
pub fn is_exact(&self) -> bool {
self.exact
}
pub fn is_empty(&self) -> bool {
self.results.is_empty()
}
pub fn len(&self) -> usize {
self.results.len()
}
pub fn first(&self) -> Option<&str> {
self.results.first().map(String::as_str)
}
pub fn results(&self) -> &[String] {
&self.results
}
/// Returns the results converted into markup
/// for displaying in a UI
pub fn to_markup(&self) -> String {
let mut markup = if !self.exact {
let mut msg = String::from("Failed to exactly resolve the symbol. This is probably because rust_analyzer does not yet support traits.");
if !self.results.is_empty() {
msg.push_str(" \nThese items were found instead:");
}
msg.push_str("\n\n---\n");
msg
} else {
String::new()
};
markup.push_str(&self.results.join("\n\n---\n"));
markup
}
}
fn hover_text(docs: Option<String>, desc: Option<String>) -> Option<String> {
match (desc, docs) {
(Some(desc), docs) => Some(rust_code_markup_with_doc(desc, docs)),
(None, Some(docs)) => Some(docs),
_ => None,
}
}
fn hover_text_from_name_kind(db: &RootDatabase, def: NameDefinition) -> Option<String> {
return match def {
NameDefinition::Macro(it) => {
let src = it.source(db);
hover_text(src.value.doc_comment_text(), Some(macro_label(&src.value)))
}
NameDefinition::StructField(it) => {
let src = it.source(db);
match src.value {
hir::FieldSource::Named(it) => hover_text(it.doc_comment_text(), it.short_label()),
_ => None,
}
}
NameDefinition::ModuleDef(it) => match it {
hir::ModuleDef::Module(it) => match it.definition_source(db).value {
hir::ModuleSource::Module(it) => {
hover_text(it.doc_comment_text(), it.short_label())
}
_ => None,
},
hir::ModuleDef::Function(it) => from_def_source(db, it),
hir::ModuleDef::Adt(Adt::Struct(it)) => from_def_source(db, it),
hir::ModuleDef::Adt(Adt::Union(it)) => from_def_source(db, it),
hir::ModuleDef::Adt(Adt::Enum(it)) => from_def_source(db, it),
hir::ModuleDef::EnumVariant(it) => from_def_source(db, it),
hir::ModuleDef::Const(it) => from_def_source(db, it),
hir::ModuleDef::Static(it) => from_def_source(db, it),
hir::ModuleDef::Trait(it) => from_def_source(db, it),
hir::ModuleDef::TypeAlias(it) => from_def_source(db, it),
hir::ModuleDef::BuiltinType(it) => Some(it.to_string()),
},
NameDefinition::Local(it) => {
Some(rust_code_markup(it.ty(db).display_truncated(db, None).to_string()))
}
NameDefinition::TypeParam(_) | NameDefinition::SelfType(_) => {
// FIXME: Hover for generic param
None
}
};
fn from_def_source<A, D>(db: &RootDatabase, def: D) -> Option<String>
where
D: HasSource<Ast = A>,
A: ast::DocCommentsOwner + ast::NameOwner + ShortLabel,
{
let src = def.source(db);
hover_text(src.value.doc_comment_text(), src.value.short_label())
}
}
pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option<RangeInfo<HoverResult>> {
let sema = Semantics::new(db);
let file = sema.parse(position.file_id).syntax().clone();
let token = pick_best(file.token_at_offset(position.offset))?;
let token = sema.descend_into_macros(token);
let mut res = HoverResult::new();
if let Some((node, name_kind)) = match_ast! {
match (token.parent()) {
ast::NameRef(name_ref) => {
classify_name_ref(&sema, &name_ref).map(|d| (name_ref.syntax().clone(), d))
},
ast::Name(name) => {
classify_name(&sema, &name).map(|d| (name.syntax().clone(), d))
},
_ => None,
}
} {
let range = sema.original_range(&node).range;
res.extend(hover_text_from_name_kind(db, name_kind));
if !res.is_empty() {
return Some(RangeInfo::new(range, res));
}
}
let node = token
.ancestors()
.find(|n| ast::Expr::cast(n.clone()).is_some() || ast::Pat::cast(n.clone()).is_some())?;
// FIXME: Currently `hover::typeof` do not work inside
// macro expansion such that if the hover range is pointing to
// a string literal, the following type_of will return None.
// See also `test_hover_through_literal_string_in_macro`
let frange = sema.original_range(&node);
res.extend(type_of(db, frange).map(rust_code_markup));
if res.is_empty() {
return None;
}
let range = node.text_range();
Some(RangeInfo::new(range, res))
}
fn pick_best(tokens: TokenAtOffset<SyntaxToken>) -> Option<SyntaxToken> {
return tokens.max_by_key(priority);
fn priority(n: &SyntaxToken) -> usize {
match n.kind() {
IDENT | INT_NUMBER => 3,
L_PAREN | R_PAREN => 2,
kind if kind.is_trivia() => 0,
_ => 1,
}
}
}
pub(crate) fn type_of(db: &RootDatabase, frange: FileRange) -> Option<String> {
let sema = Semantics::new(db);
let source_file = sema.parse(frange.file_id);
let leaf_node = find_covering_element(source_file.syntax(), frange.range);
// if we picked identifier, expand to pattern/expression
let node = leaf_node
.ancestors()
.take_while(|it| it.text_range() == leaf_node.text_range())
.find(|it| ast::Expr::cast(it.clone()).is_some() || ast::Pat::cast(it.clone()).is_some())?;
let ty = if let Some(ty) = ast::Expr::cast(node.clone()).and_then(|e| sema.type_of_expr(&e)) {
ty
} else if let Some(ty) = ast::Pat::cast(node).and_then(|p| sema.type_of_pat(&p)) {
ty
} else {
return None;
};
Some(ty.display_truncated(db, None).to_string())
}
#[cfg(test)]
mod tests {
use ra_db::FileLoader;
use ra_syntax::TextRange;
use crate::mock_analysis::{
analysis_and_position, single_file_with_position, single_file_with_range,
};
fn trim_markup(s: &str) -> &str {
s.trim_start_matches("```rust\n").trim_end_matches("\n```")
}
fn trim_markup_opt(s: Option<&str>) -> Option<&str> {
s.map(trim_markup)
}
fn check_hover_result(fixture: &str, expected: &[&str]) -> String {
let (analysis, position) = analysis_and_position(fixture);
let hover = analysis.hover(position).unwrap().unwrap();
let mut results = Vec::from(hover.info.results());
results.sort();
for (markup, expected) in
results.iter().zip(expected.iter().chain(std::iter::repeat(&"<missing>")))
{
assert_eq!(trim_markup(&markup), *expected);
}
assert_eq!(hover.info.len(), expected.len());
let content = analysis.db.file_text(position.file_id);
content[hover.range].to_string()
}
fn check_hover_no_result(fixture: &str) {
let (analysis, position) = analysis_and_position(fixture);
assert!(analysis.hover(position).unwrap().is_none());
}
#[test]
fn hover_shows_type_of_an_expression() {
let (analysis, position) = single_file_with_position(
"
pub fn foo() -> u32 { 1 }
fn main() {
let foo_test = foo()<|>;
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(hover.range, TextRange::from_to(95.into(), 100.into()));
assert_eq!(trim_markup_opt(hover.info.first()), Some("u32"));
}
#[test]
fn hover_shows_fn_signature() {
// Single file with result
check_hover_result(
r#"
//- /main.rs
pub fn foo() -> u32 { 1 }
fn main() {
let foo_test = fo<|>o();
}
"#,
&["pub fn foo() -> u32"],
);
// Multiple candidates but results are ambiguous.
check_hover_result(
r#"
//- /a.rs
pub fn foo() -> u32 { 1 }
//- /b.rs
pub fn foo() -> &str { "" }
//- /c.rs
pub fn foo(a: u32, b: u32) {}
//- /main.rs
mod a;
mod b;
mod c;
fn main() {
let foo_test = fo<|>o();
}
"#,
&["{unknown}"],
);
}
#[test]
fn hover_shows_fn_signature_with_type_params() {
check_hover_result(
r#"
//- /main.rs
pub fn foo<'a, T: AsRef<str>>(b: &'a T) -> &'a str { }
fn main() {
let foo_test = fo<|>o();
}
"#,
&["pub fn foo<'a, T: AsRef<str>>(b: &'a T) -> &'a str"],
);
}
#[test]
fn hover_shows_fn_signature_on_fn_name() {
check_hover_result(
r#"
//- /main.rs
pub fn foo<|>(a: u32, b: u32) -> u32 {}
fn main() {
}
"#,
&["pub fn foo(a: u32, b: u32) -> u32"],
);
}
#[test]
fn hover_shows_struct_field_info() {
// Hovering over the field when instantiating
check_hover_result(
r#"
//- /main.rs
struct Foo {
field_a: u32,
}
fn main() {
let foo = Foo {
field_a<|>: 0,
};
}
"#,
&["field_a: u32"],
);
// Hovering over the field in the definition
check_hover_result(
r#"
//- /main.rs
struct Foo {
field_a<|>: u32,
}
fn main() {
let foo = Foo {
field_a: 0,
};
}
"#,
&["field_a: u32"],
);
}
#[test]
fn hover_const_static() {
check_hover_result(
r#"
//- /main.rs
const foo<|>: u32 = 0;
"#,
&["const foo: u32"],
);
check_hover_result(
r#"
//- /main.rs
static foo<|>: u32 = 0;
"#,
&["static foo: u32"],
);
}
#[test]
fn hover_omits_default_generic_types() {
check_hover_result(
r#"
//- /main.rs
struct Test<K, T = u8> {
k: K,
t: T,
}
fn main() {
let zz<|> = Test { t: 23, k: 33 };
}"#,
&["Test<i32>"],
);
}
#[test]
fn hover_some() {
let (analysis, position) = single_file_with_position(
"
enum Option<T> { Some(T) }
use Option::Some;
fn main() {
So<|>me(12);
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("Some"));
let (analysis, position) = single_file_with_position(
"
enum Option<T> { Some(T) }
use Option::Some;
fn main() {
let b<|>ar = Some(12);
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("Option<i32>"));
}
#[test]
fn hover_enum_variant() {
check_hover_result(
r#"
//- /main.rs
enum Option<T> {
/// The None variant
Non<|>e
}
"#,
&["
None
```
The None variant
"
.trim()],
);
check_hover_result(
r#"
//- /main.rs
enum Option<T> {
/// The Some variant
Some(T)
}
fn main() {
let s = Option::Som<|>e(12);
}
"#,
&["
Some
```
The Some variant
"
.trim()],
);
}
#[test]
fn hover_for_local_variable() {
let (analysis, position) = single_file_with_position("fn func(foo: i32) { fo<|>o; }");
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("i32"));
}
#[test]
fn hover_for_local_variable_pat() {
let (analysis, position) = single_file_with_position("fn func(fo<|>o: i32) {}");
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("i32"));
}
#[test]
fn hover_local_var_edge() {
let (analysis, position) = single_file_with_position(
"
fn func(foo: i32) { if true { <|>foo; }; }
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("i32"));
}
#[test]
fn hover_for_param_edge() {
let (analysis, position) = single_file_with_position("fn func(<|>foo: i32) {}");
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("i32"));
}
#[test]
fn test_type_of_for_function() {
let (analysis, range) = single_file_with_range(
"
pub fn foo() -> u32 { 1 };
fn main() {
let foo_test = <|>foo()<|>;
}
",
);
let type_name = analysis.type_of(range).unwrap().unwrap();
assert_eq!("u32", &type_name);
}
#[test]
fn test_type_of_for_expr() {
let (analysis, range) = single_file_with_range(
"
fn main() {
let foo: usize = 1;
let bar = <|>1 + foo<|>;
}
",
);
let type_name = analysis.type_of(range).unwrap().unwrap();
assert_eq!("usize", &type_name);
}
#[test]
fn test_hover_infer_associated_method_result() {
let (analysis, position) = single_file_with_position(
"
struct Thing { x: u32 }
impl Thing {
fn new() -> Thing {
Thing { x: 0 }
}
}
fn main() {
let foo_<|>test = Thing::new();
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("Thing"));
}
#[test]
fn test_hover_infer_associated_method_exact() {
let (analysis, position) = single_file_with_position(
"
struct Thing { x: u32 }
impl Thing {
fn new() -> Thing {
Thing { x: 0 }
}
}
fn main() {
let foo_test = Thing::new<|>();
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("fn new() -> Thing"));
assert_eq!(hover.info.is_exact(), true);
}
#[test]
fn test_hover_infer_associated_const_in_pattern() {
let (analysis, position) = single_file_with_position(
"
struct X;
impl X {
const C: u32 = 1;
}
fn main() {
match 1 {
X::C<|> => {},
2 => {},
_ => {}
};
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("const C: u32"));
assert_eq!(hover.info.is_exact(), true);
}
#[test]
fn test_hover_self() {
let (analysis, position) = single_file_with_position(
"
struct Thing { x: u32 }
impl Thing {
fn new() -> Self {
Self<|> { x: 0 }
}
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("Thing"));
assert_eq!(hover.info.is_exact(), true);
/* FIXME: revive these tests
let (analysis, position) = single_file_with_position(
"
struct Thing { x: u32 }
impl Thing {
fn new() -> Self<|> {
Self { x: 0 }
}
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("Thing"));
assert_eq!(hover.info.is_exact(), true);
let (analysis, position) = single_file_with_position(
"
enum Thing { A }
impl Thing {
pub fn new() -> Self<|> {
Thing::A
}
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("enum Thing"));
assert_eq!(hover.info.is_exact(), true);
let (analysis, position) = single_file_with_position(
"
enum Thing { A }
impl Thing {
pub fn thing(a: Self<|>) {
}
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("enum Thing"));
assert_eq!(hover.info.is_exact(), true);
*/
}
#[test]
fn test_hover_shadowing_pat() {
let (analysis, position) = single_file_with_position(
"
fn x() {}
fn y() {
let x = 0i32;
x<|>;
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("i32"));
assert_eq!(hover.info.is_exact(), true);
}
#[test]
fn test_hover_macro_invocation() {
let (analysis, position) = single_file_with_position(
"
macro_rules! foo {
() => {}
}
fn f() {
fo<|>o!();
}
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("macro_rules! foo"));
assert_eq!(hover.info.is_exact(), true);
}
#[test]
fn test_hover_tuple_field() {
let (analysis, position) = single_file_with_position(
"
struct TS(String, i32<|>);
",
);
let hover = analysis.hover(position).unwrap().unwrap();
assert_eq!(trim_markup_opt(hover.info.first()), Some("i32"));
assert_eq!(hover.info.is_exact(), true);
}
#[test]
fn test_hover_through_macro() {
let hover_on = check_hover_result(
"
//- /lib.rs
macro_rules! id {
($($tt:tt)*) => { $($tt)* }
}
fn foo() {}
id! {
fn bar() {
fo<|>o();
}
}
",
&["fn foo()"],
);
assert_eq!(hover_on, "foo")
}
#[test]
fn test_hover_through_expr_in_macro() {
let hover_on = check_hover_result(
"
//- /lib.rs
macro_rules! id {
($($tt:tt)*) => { $($tt)* }
}
fn foo(bar:u32) {
let a = id!(ba<|>r);
}
",
&["u32"],
);
assert_eq!(hover_on, "bar")
}
#[test]
fn test_hover_through_expr_in_macro_recursive() {
let hover_on = check_hover_result(
"
//- /lib.rs
macro_rules! id_deep {
($($tt:tt)*) => { $($tt)* }
}
macro_rules! id {
($($tt:tt)*) => { id_deep!($($tt)*) }
}
fn foo(bar:u32) {
let a = id!(ba<|>r);
}
",
&["u32"],
);
assert_eq!(hover_on, "bar")
}
#[test]
fn test_hover_through_literal_string_in_macro() {
// FIXME: Currently `hover::type_of` do not work inside
// macro expansion
check_hover_no_result(
r#"
//- /lib.rs
macro_rules! arr {
($($tt:tt)*) => { [$($tt)*)] }
}
fn foo() {
let mastered_for_itunes = "";
let _ = arr!("Tr<|>acks", &mastered_for_itunes);
}
"#,
);
}
#[test]
fn test_hover_non_ascii_space_doc() {
check_hover_result(
"
//- /lib.rs
/// <- `\u{3000}` here
fn foo() {
}
fn bar() {
fo<|>o();
}
",
&["fn foo()\n```\n\n<- `\u{3000}` here"],
);
}
}