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Auto merge of #12025 - Veykril:completion-ctx, r=Veykril

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minor: Document completion context some more
This commit is contained in:
bors 2022-04-18 14:55:31 +00:00
commit 838cc9d3cc
1 changed files with 49 additions and 26 deletions
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75
crates/ide_completion/src/context.rs
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@ -148,7 +148,11 @@ pub(crate) struct CompletionContext<'a> {
pub(super) krate: hir::Crate,
/// The module of the `scope`.
pub(super) module: hir::Module,
/// The expected name of what we are completing.
/// This is usually the parameter name of the function argument we are completing.
pub(super) expected_name: Option<NameOrNameRef>,
/// The expected type of what we are completing.
pub(super) expected_type: Option<Type>,
/// The parent function of the cursor position if it exists.
@ -157,6 +161,7 @@ pub(crate) struct CompletionContext<'a> {
pub(super) impl_def: Option<ast::Impl>,
/// The NameLike under the cursor in the original file if it exists.
pub(super) name_syntax: Option<ast::NameLike>,
/// Are we completing inside a let statement with a missing semicolon?
pub(super) incomplete_let: bool,
pub(super) completion_location: Option<ImmediateLocation>,
@ -424,6 +429,7 @@ impl<'a> CompletionContext<'a> {
let scope = sema.scope_at_offset(&token.parent()?, offset)?;
let krate = scope.krate();
let module = scope.module();
let mut locals = FxHashMap::default();
scope.process_all_names(&mut |name, scope| {
if let ScopeDef::Local(local) = scope {
@ -467,8 +473,9 @@ impl<'a> CompletionContext<'a> {
Some(ctx)
}
/// Do the attribute expansion at the current cursor position for both original file and fake file
/// as long as possible. As soon as one of the two expansions fail we stop to stay in sync.
/// Expand attributes and macro calls at the current cursor position for both the original file
/// and fake file repeatedly. As soon as one of the two expansions fail we stop so the original
/// and speculative states stay in sync.
fn expand_and_fill(
&mut self,
mut original_file: SyntaxNode,
@ -489,7 +496,9 @@ impl<'a> CompletionContext<'a> {
),
|(a, b)| parent_item(a).zip(parent_item(b)),
);
for (actual_item, item_with_fake_ident) in ancestor_items {
// first try to expand attributes as these are always the outermost macro calls
'ancestors: for (actual_item, item_with_fake_ident) in ancestor_items {
match (
self.sema.expand_attr_macro(&actual_item),
self.sema.speculative_expand_attr_macro(
@ -498,12 +507,14 @@ impl<'a> CompletionContext<'a> {
fake_ident_token.clone(),
),
) {
// maybe parent items have attributes
(None, None) => (),
// maybe parent items have attributes, so continue walking the ancestors
(None, None) => continue 'ancestors,
// successful expansions
(Some(actual_expansion), Some((fake_expansion, fake_mapped_token))) => {
let new_offset = fake_mapped_token.text_range().start();
if new_offset > actual_expansion.text_range().end() {
// offset outside of bounds from the original expansion,
// stop here to prevent problems from happening
break 'expansion;
}
original_file = actual_expansion;
@ -516,13 +527,15 @@ impl<'a> CompletionContext<'a> {
_ => break 'expansion,
}
}
// No attributes have been expanded, so look for macro_call! token trees or derive token trees
let orig_tt = match find_node_at_offset::<ast::TokenTree>(&original_file, offset) {
Some(it) => it,
None => break,
None => break 'expansion,
};
let spec_tt = match find_node_at_offset::<ast::TokenTree>(&speculative_file, offset) {
Some(it) => it,
None => break,
None => break 'expansion,
};
// Expand pseudo-derive expansion
@ -530,7 +543,7 @@ impl<'a> CompletionContext<'a> {
orig_tt.syntax().parent().and_then(ast::Meta::cast).and_then(|it| it.parent_attr()),
spec_tt.syntax().parent().and_then(ast::Meta::cast).and_then(|it| it.parent_attr()),
) {
match (
if let (Some(actual_expansion), Some((fake_expansion, fake_mapped_token))) = (
self.sema.expand_derive_as_pseudo_attr_macro(&orig_attr),
self.sema.speculative_expand_derive_as_pseudo_attr_macro(
&orig_attr,
@ -538,18 +551,15 @@ impl<'a> CompletionContext<'a> {
fake_ident_token.clone(),
),
) {
// Clearly not a derive macro
(None, None) => (),
// successful expansions
(Some(actual_expansion), Some((fake_expansion, fake_mapped_token))) => {
let new_offset = fake_mapped_token.text_range().start();
derive_ctx =
Some((actual_expansion, fake_expansion, new_offset, orig_attr));
break 'expansion;
}
// exactly one expansion failed, inconsistent state so stop expanding completely
_ => break 'expansion,
derive_ctx = Some((
actual_expansion,
fake_expansion,
fake_mapped_token.text_range().start(),
orig_attr,
));
}
// at this point we won't have any more successful expansions, so stop
break 'expansion;
}
// Expand fn-like macro calls
@ -560,12 +570,14 @@ impl<'a> CompletionContext<'a> {
let mac_call_path0 = actual_macro_call.path().as_ref().map(|s| s.syntax().text());
let mac_call_path1 =
macro_call_with_fake_ident.path().as_ref().map(|s| s.syntax().text());
// inconsistent state, stop expanding
if mac_call_path0 != mac_call_path1 {
break;
break 'expansion;
}
let speculative_args = match macro_call_with_fake_ident.token_tree() {
Some(tt) => tt,
None => break,
None => break 'expansion,
};
match (
@ -580,24 +592,30 @@ impl<'a> CompletionContext<'a> {
(Some(actual_expansion), Some((fake_expansion, fake_mapped_token))) => {
let new_offset = fake_mapped_token.text_range().start();
if new_offset > actual_expansion.text_range().end() {
break;
// offset outside of bounds from the original expansion,
// stop here to prevent problems from happening
break 'expansion;
}
original_file = actual_expansion;
speculative_file = fake_expansion;
fake_ident_token = fake_mapped_token;
offset = new_offset;
continue;
continue 'expansion;
}
_ => break,
// at least on expansion failed, we won't have anything to expand from this point
// onwards so break out
_ => break 'expansion,
}
}
break;
// none of our states have changed so stop the loop
break 'expansion;
}
self.fill(&original_file, speculative_file, offset, derive_ctx);
}
/// Calculate the expected type and name of the cursor position.
fn expected_type_and_name(&self) -> (Option<Type>, Option<NameOrNameRef>) {
let mut node = match self.token.parent() {
Some(it) => it,
@ -734,6 +752,8 @@ impl<'a> CompletionContext<'a> {
}
}
/// Fill the completion context, this is what does semantic reasoning about the surrounding context
/// of the completion location.
fn fill(
&mut self,
original_file: &SyntaxNode,
@ -1067,6 +1087,7 @@ fn pattern_context_for(original_file: &SyntaxNode, pat: ast::Pat) -> PatternCont
}
}
/// Attempts to find `node` inside `syntax` via `node`'s text range.
fn find_node_in_file<N: AstNode>(syntax: &SyntaxNode, node: &N) -> Option<N> {
let syntax_range = syntax.text_range();
let range = node.syntax().text_range();
@ -1074,7 +1095,8 @@ fn find_node_in_file<N: AstNode>(syntax: &SyntaxNode, node: &N) -> Option<N> {
syntax.covering_element(intersection).ancestors().find_map(N::cast)
}
/// Compensates for the offset introduced by the fake ident
/// Attempts to find `node` inside `syntax` via `node`'s text range while compensating
/// for the offset introduced by the fake ident.
/// This is wrong if `node` comes before the insertion point! Use `find_node_in_file` instead.
fn find_node_in_file_compensated<N: AstNode>(syntax: &SyntaxNode, node: &N) -> Option<N> {
let syntax_range = syntax.text_range();
@ -1143,6 +1165,7 @@ const OP_TRAIT_LANG_NAMES: &[&str] = &[
"shr",
"sub",
];
#[cfg(test)]
mod tests {
use expect_test::{expect, Expect};