Merge #4700

4700: Add top level keywords completion r=matklad a=mcrakhman

This fixes the following issue: https://github.com/rust-analyzer/rust-analyzer/issues/4566. 

Also added simple logic which filters the keywords which can be used with unsafe on the top level.   

Co-authored-by: Mikhail Rakhmanov <rakhmanov.m@gmail.com>
Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

crates/ra_ide/src/completion.rs

@@ -15,6 +15,7 @@ mod complete_unqualified_path;
 mod complete_postfix;
 mod complete_macro_in_item_position;
 mod complete_trait_impl;
+mod patterns;
 #[cfg(test)]
 mod test_utils;
 

crates/ra_ide/src/completion/completion_context.rs

@@ -5,12 +5,17 @@ use ra_db::SourceDatabase;
 use ra_ide_db::RootDatabase;
 use ra_syntax::{
     algo::{find_covering_element, find_node_at_offset},
-    ast, match_ast, AstNode,
+    ast, match_ast, AstNode, NodeOrToken,
     SyntaxKind::*,
     SyntaxNode, SyntaxToken, TextRange, TextSize,
 };
 use ra_text_edit::Indel;
 
+use super::patterns::{
+    has_bind_pat_parent, has_block_expr_parent, has_impl_as_prev_sibling, has_impl_parent,
+    has_item_list_or_source_file_parent, has_ref_parent, has_trait_as_prev_sibling,
+    has_trait_parent, if_is_prev, is_in_loop_body, is_match_arm, unsafe_is_prev,
+};
 use crate::{call_info::ActiveParameter, completion::CompletionConfig, FilePosition};
 use test_utils::mark;
 
@@ -60,6 +65,18 @@ pub(crate) struct CompletionContext<'a> {
     pub(super) is_path_type: bool,
     pub(super) has_type_args: bool,
     pub(super) attribute_under_caret: Option<ast::Attr>,
+    pub(super) unsafe_is_prev: bool,
+    pub(super) if_is_prev: bool,
+    pub(super) block_expr_parent: bool,
+    pub(super) bind_pat_parent: bool,
+    pub(super) ref_pat_parent: bool,
+    pub(super) in_loop_body: bool,
+    pub(super) has_trait_parent: bool,
+    pub(super) has_impl_parent: bool,
+    pub(super) trait_as_prev_sibling: bool,
+    pub(super) impl_as_prev_sibling: bool,
+    pub(super) is_match_arm: bool,
+    pub(super) has_item_list_or_source_file_parent: bool,
 }
 
 impl<'a> CompletionContext<'a> {
@@ -118,6 +135,18 @@ impl<'a> CompletionContext<'a> {
             has_type_args: false,
             dot_receiver_is_ambiguous_float_literal: false,
             attribute_under_caret: None,
+            unsafe_is_prev: false,
+            in_loop_body: false,
+            ref_pat_parent: false,
+            bind_pat_parent: false,
+            block_expr_parent: false,
+            has_trait_parent: false,
+            has_impl_parent: false,
+            trait_as_prev_sibling: false,
+            impl_as_prev_sibling: false,
+            if_is_prev: false,
+            is_match_arm: false,
+            has_item_list_or_source_file_parent: false,
         };
 
         let mut original_file = original_file.syntax().clone();
@@ -159,7 +188,7 @@ impl<'a> CompletionContext<'a> {
                 break;
             }
         }
-
+        ctx.fill_keyword_patterns(&hypothetical_file, offset);
         ctx.fill(&original_file, hypothetical_file, offset);
         Some(ctx)
     }
@@ -188,6 +217,24 @@ impl<'a> CompletionContext<'a> {
         self.sema.scope_at_offset(&self.token.parent(), self.offset)
     }
 
+    fn fill_keyword_patterns(&mut self, file_with_fake_ident: &SyntaxNode, offset: TextSize) {
+        let fake_ident_token = file_with_fake_ident.token_at_offset(offset).right_biased().unwrap();
+        let syntax_element = NodeOrToken::Token(fake_ident_token.clone());
+        self.block_expr_parent = has_block_expr_parent(syntax_element.clone());
+        self.unsafe_is_prev = unsafe_is_prev(syntax_element.clone());
+        self.if_is_prev = if_is_prev(syntax_element.clone());
+        self.bind_pat_parent = has_bind_pat_parent(syntax_element.clone());
+        self.ref_pat_parent = has_ref_parent(syntax_element.clone());
+        self.in_loop_body = is_in_loop_body(syntax_element.clone());
+        self.has_trait_parent = has_trait_parent(syntax_element.clone());
+        self.has_impl_parent = has_impl_parent(syntax_element.clone());
+        self.impl_as_prev_sibling = has_impl_as_prev_sibling(syntax_element.clone());
+        self.trait_as_prev_sibling = has_trait_as_prev_sibling(syntax_element.clone());
+        self.is_match_arm = is_match_arm(syntax_element.clone());
+        self.has_item_list_or_source_file_parent =
+            has_item_list_or_source_file_parent(syntax_element.clone());
+    }
+
     fn fill(
         &mut self,
         original_file: &SyntaxNode,

crates/ra_ide/src/completion/completion_item.rs

@@ -125,6 +125,32 @@ pub enum CompletionItemKind {
     Attribute,
 }
 
+impl CompletionItemKind {
+    #[cfg(test)]
+    pub(crate) fn tag(&self) -> &'static str {
+        match self {
+            CompletionItemKind::Snippet => "sn",
+            CompletionItemKind::Keyword => "kw",
+            CompletionItemKind::Module => "md",
+            CompletionItemKind::Function => "fn",
+            CompletionItemKind::BuiltinType => "bt",
+            CompletionItemKind::Struct => "st",
+            CompletionItemKind::Enum => "en",
+            CompletionItemKind::EnumVariant => "ev",
+            CompletionItemKind::Binding => "bn",
+            CompletionItemKind::Field => "fd",
+            CompletionItemKind::Static => "sc",
+            CompletionItemKind::Const => "ct",
+            CompletionItemKind::Trait => "tt",
+            CompletionItemKind::TypeAlias => "ta",
+            CompletionItemKind::Method => "me",
+            CompletionItemKind::TypeParam => "tp",
+            CompletionItemKind::Macro => "ma",
+            CompletionItemKind::Attribute => "at",
+        }
+    }
+}
+
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 pub(crate) enum CompletionKind {
     /// Parser-based keyword completion.

crates/ra_ide/src/completion/patterns.rs

@@ -0,0 +1,194 @@
+//! Patterns telling us certain facts about current syntax element, they are used in completion context
+
+use ra_syntax::{
+    algo::non_trivia_sibling,
+    ast::{self, LoopBodyOwner},
+    match_ast, AstNode, Direction, NodeOrToken, SyntaxElement,
+    SyntaxKind::*,
+    SyntaxNode, SyntaxToken,
+};
+
+#[cfg(test)]
+use crate::completion::test_utils::check_pattern_is_applicable;
+
+pub(crate) fn has_trait_parent(element: SyntaxElement) -> bool {
+    not_same_range_ancestor(element)
+        .filter(|it| it.kind() == ITEM_LIST)
+        .and_then(|it| it.parent())
+        .filter(|it| it.kind() == TRAIT_DEF)
+        .is_some()
+}
+#[test]
+fn test_has_trait_parent() {
+    check_pattern_is_applicable(r"trait A { f<|> }", has_trait_parent);
+}
+
+pub(crate) fn has_impl_parent(element: SyntaxElement) -> bool {
+    not_same_range_ancestor(element)
+        .filter(|it| it.kind() == ITEM_LIST)
+        .and_then(|it| it.parent())
+        .filter(|it| it.kind() == IMPL_DEF)
+        .is_some()
+}
+#[test]
+fn test_has_impl_parent() {
+    check_pattern_is_applicable(r"impl A { f<|> }", has_impl_parent);
+}
+
+pub(crate) fn has_block_expr_parent(element: SyntaxElement) -> bool {
+    not_same_range_ancestor(element).filter(|it| it.kind() == BLOCK_EXPR).is_some()
+}
+#[test]
+fn test_has_block_expr_parent() {
+    check_pattern_is_applicable(r"fn my_fn() { let a = 2; f<|> }", has_block_expr_parent);
+}
+
+pub(crate) fn has_bind_pat_parent(element: SyntaxElement) -> bool {
+    element.ancestors().find(|it| it.kind() == BIND_PAT).is_some()
+}
+#[test]
+fn test_has_bind_pat_parent() {
+    check_pattern_is_applicable(r"fn my_fn(m<|>) {}", has_bind_pat_parent);
+    check_pattern_is_applicable(r"fn my_fn() { let m<|> }", has_bind_pat_parent);
+}
+
+pub(crate) fn has_ref_parent(element: SyntaxElement) -> bool {
+    not_same_range_ancestor(element)
+        .filter(|it| it.kind() == REF_PAT || it.kind() == REF_EXPR)
+        .is_some()
+}
+#[test]
+fn test_has_ref_parent() {
+    check_pattern_is_applicable(r"fn my_fn(&m<|>) {}", has_ref_parent);
+    check_pattern_is_applicable(r"fn my() { let &m<|> }", has_ref_parent);
+}
+
+pub(crate) fn has_item_list_or_source_file_parent(element: SyntaxElement) -> bool {
+    let ancestor = not_same_range_ancestor(element);
+    if !ancestor.is_some() {
+        return true;
+    }
+    ancestor.filter(|it| it.kind() == SOURCE_FILE || it.kind() == ITEM_LIST).is_some()
+}
+#[test]
+fn test_has_item_list_or_source_file_parent() {
+    check_pattern_is_applicable(r"i<|>", has_item_list_or_source_file_parent);
+    check_pattern_is_applicable(r"impl { f<|> }", has_item_list_or_source_file_parent);
+}
+
+pub(crate) fn is_match_arm(element: SyntaxElement) -> bool {
+    not_same_range_ancestor(element.clone()).filter(|it| it.kind() == MATCH_ARM).is_some()
+        && previous_sibling_or_ancestor_sibling(element)
+            .and_then(|it| it.into_token())
+            .filter(|it| it.kind() == FAT_ARROW)
+            .is_some()
+}
+#[test]
+fn test_is_match_arm() {
+    check_pattern_is_applicable(r"fn my_fn() { match () { () => m<|> } }", is_match_arm);
+}
+
+pub(crate) fn unsafe_is_prev(element: SyntaxElement) -> bool {
+    element
+        .into_token()
+        .and_then(|it| previous_non_trivia_token(it))
+        .filter(|it| it.kind() == UNSAFE_KW)
+        .is_some()
+}
+#[test]
+fn test_unsafe_is_prev() {
+    check_pattern_is_applicable(r"unsafe i<|>", unsafe_is_prev);
+}
+
+pub(crate) fn if_is_prev(element: SyntaxElement) -> bool {
+    element
+        .into_token()
+        .and_then(|it| previous_non_trivia_token(it))
+        .filter(|it| it.kind() == IF_KW)
+        .is_some()
+}
+#[test]
+fn test_if_is_prev() {
+    check_pattern_is_applicable(r"if l<|>", if_is_prev);
+}
+
+pub(crate) fn has_trait_as_prev_sibling(element: SyntaxElement) -> bool {
+    previous_sibling_or_ancestor_sibling(element).filter(|it| it.kind() == TRAIT_DEF).is_some()
+}
+#[test]
+fn test_has_trait_as_prev_sibling() {
+    check_pattern_is_applicable(r"trait A w<|> {}", has_trait_as_prev_sibling);
+}
+
+pub(crate) fn has_impl_as_prev_sibling(element: SyntaxElement) -> bool {
+    previous_sibling_or_ancestor_sibling(element).filter(|it| it.kind() == IMPL_DEF).is_some()
+}
+#[test]
+fn test_has_impl_as_prev_sibling() {
+    check_pattern_is_applicable(r"impl A w<|> {}", has_impl_as_prev_sibling);
+}
+
+pub(crate) fn is_in_loop_body(element: SyntaxElement) -> bool {
+    let leaf = match element {
+        NodeOrToken::Node(node) => node,
+        NodeOrToken::Token(token) => token.parent(),
+    };
+    for node in leaf.ancestors() {
+        if node.kind() == FN_DEF || node.kind() == LAMBDA_EXPR {
+            break;
+        }
+        let loop_body = match_ast! {
+            match node {
+                ast::ForExpr(it) => it.loop_body(),
+                ast::WhileExpr(it) => it.loop_body(),
+                ast::LoopExpr(it) => it.loop_body(),
+                _ => None,
+            }
+        };
+        if let Some(body) = loop_body {
+            if body.syntax().text_range().contains_range(leaf.text_range()) {
+                return true;
+            }
+        }
+    }
+    false
+}
+
+fn not_same_range_ancestor(element: SyntaxElement) -> Option<SyntaxNode> {
+    element
+        .ancestors()
+        .take_while(|it| it.text_range() == element.text_range())
+        .last()
+        .and_then(|it| it.parent())
+}
+
+fn previous_non_trivia_token(token: SyntaxToken) -> Option<SyntaxToken> {
+    let mut token = token.prev_token();
+    while let Some(inner) = token.clone() {
+        if !inner.kind().is_trivia() {
+            return Some(inner);
+        } else {
+            token = inner.prev_token();
+        }
+    }
+    None
+}
+
+fn previous_sibling_or_ancestor_sibling(element: SyntaxElement) -> Option<SyntaxElement> {
+    let token_sibling = non_trivia_sibling(element.clone(), Direction::Prev);
+    if let Some(sibling) = token_sibling {
+        Some(sibling)
+    } else {
+        // if not trying to find first ancestor which has such a sibling
+        let node = match element {
+            NodeOrToken::Node(node) => node,
+            NodeOrToken::Token(token) => token.parent(),
+        };
+        let range = node.text_range();
+        let top_node = node.ancestors().take_while(|it| it.text_range() == range).last()?;
+        let prev_sibling_node = top_node.ancestors().find(|it| {
+            non_trivia_sibling(NodeOrToken::Node(it.to_owned()), Direction::Prev).is_some()
+        })?;
+        non_trivia_sibling(NodeOrToken::Node(prev_sibling_node), Direction::Prev)
+    }
+}

crates/ra_ide/src/completion/test_utils.rs

@@ -5,25 +5,63 @@ use crate::{
     mock_analysis::{analysis_and_position, single_file_with_position},
     CompletionItem,
 };
+use hir::Semantics;
+use ra_syntax::{AstNode, NodeOrToken, SyntaxElement};
 
 pub(crate) fn do_completion(code: &str, kind: CompletionKind) -> Vec<CompletionItem> {
     do_completion_with_options(code, kind, &CompletionConfig::default())
 }
 
+pub(crate) fn completion_list(code: &str, kind: CompletionKind) -> String {
+    completion_list_with_options(code, kind, &CompletionConfig::default())
+}
+
 pub(crate) fn do_completion_with_options(
     code: &str,
     kind: CompletionKind,
     options: &CompletionConfig,
 ) -> Vec<CompletionItem> {
+    let mut kind_completions: Vec<CompletionItem> = get_all_completion_items(code, options)
+        .into_iter()
+        .filter(|c| c.completion_kind == kind)
+        .collect();
+    kind_completions.sort_by(|l, r| l.label().cmp(r.label()));
+    kind_completions
+}
+
+fn get_all_completion_items(code: &str, options: &CompletionConfig) -> Vec<CompletionItem> {
     let (analysis, position) = if code.contains("//-") {
         analysis_and_position(code)
     } else {
         single_file_with_position(code)
     };
-    let completions = analysis.completions(options, position).unwrap().unwrap();
-    let completion_items: Vec<CompletionItem> = completions.into();
-    let mut kind_completions: Vec<CompletionItem> =
-        completion_items.into_iter().filter(|c| c.completion_kind == kind).collect();
+    analysis.completions(options, position).unwrap().unwrap().into()
+}
+
+pub(crate) fn completion_list_with_options(
+    code: &str,
+    kind: CompletionKind,
+    options: &CompletionConfig,
+) -> String {
+    let mut kind_completions: Vec<CompletionItem> = get_all_completion_items(code, options)
+        .into_iter()
+        .filter(|c| c.completion_kind == kind)
+        .collect();
     kind_completions.sort_by_key(|c| c.label().to_owned());
     kind_completions
+        .into_iter()
+        .map(|it| format!("{} {}\n", it.kind().unwrap().tag(), it.label()))
+        .collect()
+}
+
+pub(crate) fn check_pattern_is_applicable(code: &str, check: fn(SyntaxElement) -> bool) {
+    let (analysis, pos) = single_file_with_position(code);
+    analysis
+        .with_db(|db| {
+            let sema = Semantics::new(db);
+            let original_file = sema.parse(pos.file_id);
+            let token = original_file.syntax().token_at_offset(pos.offset).left_biased().unwrap();
+            assert!(check(NodeOrToken::Token(token)));
+        })
+        .unwrap();
 }