Send LSP Completion Item Kind (#11443)

# Description

This commit fills in the completion item kind into the
`textDocument/completion` response so that LSP client can present more
information to the user.

It is an improvement in the context of #10794

# User-Facing Changes

Improved information display in editor's intelli-sense menu


![output](https://github.com/nushell/nushell/assets/16558417/991dc0a9-45d1-4718-8f22-29002d687b93)

crates/nu-cli/src/completions/base.rs

@@ -13,13 +13,13 @@ pub trait Completer {
         offset: usize,
         pos: usize,
         options: &CompletionOptions,
-    ) -> Vec<Suggestion>;
+    ) -> Vec<SemanticSuggestion>;
 
     fn get_sort_by(&self) -> SortBy {
         SortBy::Ascending
     }
 
-    fn sort(&self, items: Vec<Suggestion>, prefix: Vec<u8>) -> Vec<Suggestion> {
+    fn sort(&self, items: Vec<SemanticSuggestion>, prefix: Vec<u8>) -> Vec<SemanticSuggestion> {
         let prefix_str = String::from_utf8_lossy(&prefix).to_string();
         let mut filtered_items = items;
 
@@ -27,13 +27,13 @@ pub trait Completer {
         match self.get_sort_by() {
             SortBy::LevenshteinDistance => {
                 filtered_items.sort_by(|a, b| {
-                    let a_distance = levenshtein_distance(&prefix_str, &a.value);
+                    let a_distance = levenshtein_distance(&prefix_str, &a.suggestion.value);
-                    let b_distance = levenshtein_distance(&prefix_str, &b.value);
+                    let b_distance = levenshtein_distance(&prefix_str, &b.suggestion.value);
                     a_distance.cmp(&b_distance)
                 });
             }
             SortBy::Ascending => {
-                filtered_items.sort_by(|a, b| a.value.cmp(&b.value));
+                filtered_items.sort_by(|a, b| a.suggestion.value.cmp(&b.suggestion.value));
             }
             SortBy::None => {}
         };
@@ -41,3 +41,25 @@ pub trait Completer {
         filtered_items
     }
 }
+
+#[derive(Debug, Default, PartialEq)]
+pub struct SemanticSuggestion {
+    pub suggestion: Suggestion,
+    pub kind: Option<SuggestionKind>,
+}
+
+// TODO: think about name: maybe suggestion context?
+#[derive(Clone, Debug, PartialEq)]
+pub enum SuggestionKind {
+    Command(nu_protocol::engine::CommandType),
+    Type(nu_protocol::Type),
+}
+
+impl From<Suggestion> for SemanticSuggestion {
+    fn from(suggestion: Suggestion) -> Self {
+        Self {
+            suggestion,
+            ..Default::default()
+        }
+    }
+}

crates/nu-cli/src/completions/command_completions.rs

@@ -1,4 +1,7 @@
-use crate::completions::{Completer, CompletionOptions, MatchAlgorithm, SortBy};
+use crate::{
+    completions::{Completer, CompletionOptions, MatchAlgorithm, SortBy},
+    SuggestionKind,
+};
 use nu_parser::FlatShape;
 use nu_protocol::{
     engine::{CachedFile, EngineState, StateWorkingSet},
@@ -7,6 +10,8 @@ use nu_protocol::{
 use reedline::Suggestion;
 use std::sync::Arc;
 
+use super::SemanticSuggestion;
+
 pub struct CommandCompletion {
     engine_state: Arc<EngineState>,
     flattened: Vec<(Span, FlatShape)>,
@@ -83,7 +88,7 @@ impl CommandCompletion {
         offset: usize,
         find_externals: bool,
         match_algorithm: MatchAlgorithm,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         let partial = working_set.get_span_contents(span);
 
         let filter_predicate = |command: &[u8]| match_algorithm.matches_u8(command, partial);
@@ -91,13 +96,16 @@ impl CommandCompletion {
         let mut results = working_set
             .find_commands_by_predicate(filter_predicate, true)
             .into_iter()
-            .map(move |x| Suggestion {
+            .map(move |x| SemanticSuggestion {
+                suggestion: Suggestion {
                     value: String::from_utf8_lossy(&x.0).to_string(),
                     description: x.1,
                     style: None,
                     extra: None,
                     span: reedline::Span::new(span.start - offset, span.end - offset),
                     append_whitespace: true,
+                },
+                kind: Some(SuggestionKind::Command(x.2)),
             })
             .collect::<Vec<_>>();
 
@@ -108,27 +116,34 @@ impl CommandCompletion {
             let results_external = self
                 .external_command_completion(&partial, match_algorithm)
                 .into_iter()
-                .map(move |x| Suggestion {
+                .map(move |x| SemanticSuggestion {
+                    suggestion: Suggestion {
                         value: x,
                         description: None,
                         style: None,
                         extra: None,
                         span: reedline::Span::new(span.start - offset, span.end - offset),
                         append_whitespace: true,
+                    },
+                    // TODO: is there a way to create a test?
+                    kind: None,
                 });
 
             let results_strings: Vec<String> =
-                results.clone().into_iter().map(|x| x.value).collect();
+                results.iter().map(|x| x.suggestion.value.clone()).collect();
 
             for external in results_external {
-                if results_strings.contains(&external.value) {
+                if results_strings.contains(&external.suggestion.value) {
-                    results.push(Suggestion {
+                    results.push(SemanticSuggestion {
-                        value: format!("^{}", external.value),
+                        suggestion: Suggestion {
+                            value: format!("^{}", external.suggestion.value),
                             description: None,
                             style: None,
                             extra: None,
-                        span: external.span,
+                            span: external.suggestion.span,
                             append_whitespace: true,
+                        },
+                        kind: external.kind,
                     })
                 } else {
                     results.push(external)
@@ -151,7 +166,7 @@ impl Completer for CommandCompletion {
         offset: usize,
         pos: usize,
         options: &CompletionOptions,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         let last = self
             .flattened
             .iter()

crates/nu-cli/src/completions/completer.rs

@@ -14,6 +14,8 @@ use reedline::{Completer as ReedlineCompleter, Suggestion};
 use std::str;
 use std::sync::Arc;
 
+use super::base::{SemanticSuggestion, SuggestionKind};
+
 #[derive(Clone)]
 pub struct NuCompleter {
     engine_state: Arc<EngineState>,
@@ -28,6 +30,10 @@ impl NuCompleter {
         }
     }
 
+    pub fn fetch_completions_at(&mut self, line: &str, pos: usize) -> Vec<SemanticSuggestion> {
+        self.completion_helper(line, pos)
+    }
+
     // Process the completion for a given completer
     fn process_completion<T: Completer>(
         &self,
@@ -37,7 +43,7 @@ impl NuCompleter {
         new_span: Span,
         offset: usize,
         pos: usize,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         let config = self.engine_state.get_config();
 
         let options = CompletionOptions {
@@ -62,7 +68,7 @@ impl NuCompleter {
         spans: &[String],
         offset: usize,
         span: Span,
-    ) -> Option<Vec<Suggestion>> {
+    ) -> Option<Vec<SemanticSuggestion>> {
         let block = self.engine_state.get_block(block_id);
         let mut callee_stack = self
             .stack
@@ -107,7 +113,7 @@ impl NuCompleter {
         None
     }
 
-    fn completion_helper(&mut self, line: &str, pos: usize) -> Vec<Suggestion> {
+    fn completion_helper(&mut self, line: &str, pos: usize) -> Vec<SemanticSuggestion> {
         let mut working_set = StateWorkingSet::new(&self.engine_state);
         let offset = working_set.next_span_start();
         // TODO: Callers should be trimming the line themselves
@@ -397,6 +403,9 @@ impl NuCompleter {
 impl ReedlineCompleter for NuCompleter {
     fn complete(&mut self, line: &str, pos: usize) -> Vec<Suggestion> {
         self.completion_helper(line, pos)
+            .into_iter()
+            .map(|s| s.suggestion)
+            .collect()
     }
 }
 
@@ -454,11 +463,12 @@ pub fn map_value_completions<'a>(
     list: impl Iterator<Item = &'a Value>,
     span: Span,
     offset: usize,
-) -> Vec<Suggestion> {
+) -> Vec<SemanticSuggestion> {
     list.filter_map(move |x| {
         // Match for string values
         if let Ok(s) = x.coerce_string() {
-            return Some(Suggestion {
+            return Some(SemanticSuggestion {
+                suggestion: Suggestion {
                     value: s,
                     description: None,
                     style: None,
@@ -468,6 +478,8 @@ pub fn map_value_completions<'a>(
                         end: span.end - offset,
                     },
                     append_whitespace: false,
+                },
+                kind: Some(SuggestionKind::Type(x.get_type())),
             });
         }
 
@@ -516,7 +528,10 @@ pub fn map_value_completions<'a>(
                 }
             });
 
-            return Some(suggestion);
+            return Some(SemanticSuggestion {
+                suggestion,
+                kind: Some(SuggestionKind::Type(x.get_type())),
+            });
         }
 
         None
@@ -568,13 +583,13 @@ mod completer_tests {
             // Test whether the result begins with the expected value
             result
                 .iter()
-                .for_each(|x| assert!(x.value.starts_with(begins_with)));
+                .for_each(|x| assert!(x.suggestion.value.starts_with(begins_with)));
 
             // Test whether the result contains all the expected values
             assert_eq!(
                 result
                     .iter()
-                    .map(|x| expected_values.contains(&x.value.as_str()))
+                    .map(|x| expected_values.contains(&x.suggestion.value.as_str()))
                     .filter(|x| *x)
                     .count(),
                 expected_values.len(),

crates/nu-cli/src/completions/custom_completions.rs

@@ -7,10 +7,10 @@ use nu_protocol::{
     PipelineData, Span, Type, Value,
 };
 use nu_utils::IgnoreCaseExt;
-use reedline::Suggestion;
 use std::collections::HashMap;
 use std::sync::Arc;
 
+use super::base::SemanticSuggestion;
 use super::completer::map_value_completions;
 
 pub struct CustomCompletion {
@@ -42,7 +42,7 @@ impl Completer for CustomCompletion {
         offset: usize,
         pos: usize,
         completion_options: &CompletionOptions,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         // Line position
         let line_pos = pos - offset;
 
@@ -145,15 +145,22 @@ impl Completer for CustomCompletion {
     }
 }
 
-fn filter(prefix: &[u8], items: Vec<Suggestion>, options: &CompletionOptions) -> Vec<Suggestion> {
+fn filter(
+    prefix: &[u8],
+    items: Vec<SemanticSuggestion>,
+    options: &CompletionOptions,
+) -> Vec<SemanticSuggestion> {
     items
         .into_iter()
         .filter(|it| match options.match_algorithm {
             MatchAlgorithm::Prefix => match (options.case_sensitive, options.positional) {
-                (true, true) => it.value.as_bytes().starts_with(prefix),
+                (true, true) => it.suggestion.value.as_bytes().starts_with(prefix),
-                (true, false) => it.value.contains(std::str::from_utf8(prefix).unwrap_or("")),
+                (true, false) => it
+                    .suggestion
+                    .value
+                    .contains(std::str::from_utf8(prefix).unwrap_or("")),
                 (false, positional) => {
-                    let value = it.value.to_folded_case();
+                    let value = it.suggestion.value.to_folded_case();
                     let prefix = std::str::from_utf8(prefix).unwrap_or("").to_folded_case();
                     if positional {
                         value.starts_with(&prefix)
@@ -164,7 +171,7 @@ fn filter(prefix: &[u8], items: Vec<Suggestion>, options: &CompletionOptions) ->
             },
             MatchAlgorithm::Fuzzy => options
                 .match_algorithm
-                .matches_u8(it.value.as_bytes(), prefix),
+                .matches_u8(it.suggestion.value.as_bytes(), prefix),
         })
         .collect()
 }

crates/nu-cli/src/completions/directory_completions.rs

@@ -11,6 +11,8 @@ use reedline::Suggestion;
 use std::path::{Path, MAIN_SEPARATOR as SEP};
 use std::sync::Arc;
 
+use super::SemanticSuggestion;
+
 #[derive(Clone)]
 pub struct DirectoryCompletion {
     engine_state: Arc<EngineState>,
@@ -35,7 +37,7 @@ impl Completer for DirectoryCompletion {
         offset: usize,
         _: usize,
         options: &CompletionOptions,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         let AdjustView { prefix, span, .. } = adjust_if_intermediate(&prefix, working_set, span);
 
         // Filter only the folders
@@ -48,7 +50,8 @@ impl Completer for DirectoryCompletion {
             &self.stack,
         )
         .into_iter()
-        .map(move |x| Suggestion {
+        .map(move |x| SemanticSuggestion {
+            suggestion: Suggestion {
                 value: x.1,
                 description: None,
                 style: x.2,
@@ -58,6 +61,9 @@ impl Completer for DirectoryCompletion {
                     end: x.0.end - offset,
                 },
                 append_whitespace: false,
+            },
+            // TODO????
+            kind: None,
         })
         .collect();
 
@@ -65,7 +71,7 @@ impl Completer for DirectoryCompletion {
     }
 
     // Sort results prioritizing the non hidden folders
-    fn sort(&self, items: Vec<Suggestion>, prefix: Vec<u8>) -> Vec<Suggestion> {
+    fn sort(&self, items: Vec<SemanticSuggestion>, prefix: Vec<u8>) -> Vec<SemanticSuggestion> {
         let prefix_str = String::from_utf8_lossy(&prefix).to_string();
 
         // Sort items
@@ -75,15 +81,16 @@ impl Completer for DirectoryCompletion {
             SortBy::Ascending => {
                 sorted_items.sort_by(|a, b| {
                     // Ignore trailing slashes in folder names when sorting
-                    a.value
+                    a.suggestion
+                        .value
                         .trim_end_matches(SEP)
-                        .cmp(b.value.trim_end_matches(SEP))
+                        .cmp(b.suggestion.value.trim_end_matches(SEP))
                 });
             }
             SortBy::LevenshteinDistance => {
                 sorted_items.sort_by(|a, b| {
-                    let a_distance = levenshtein_distance(&prefix_str, &a.value);
+                    let a_distance = levenshtein_distance(&prefix_str, &a.suggestion.value);
-                    let b_distance = levenshtein_distance(&prefix_str, &b.value);
+                    let b_distance = levenshtein_distance(&prefix_str, &b.suggestion.value);
                     a_distance.cmp(&b_distance)
                 });
             }
@@ -91,11 +98,11 @@ impl Completer for DirectoryCompletion {
         }
 
         // Separate the results between hidden and non hidden
-        let mut hidden: Vec<Suggestion> = vec![];
+        let mut hidden: Vec<SemanticSuggestion> = vec![];
-        let mut non_hidden: Vec<Suggestion> = vec![];
+        let mut non_hidden: Vec<SemanticSuggestion> = vec![];
 
         for item in sorted_items.into_iter() {
-            let item_path = Path::new(&item.value);
+            let item_path = Path::new(&item.suggestion.value);
 
             if let Some(value) = item_path.file_name() {
                 if let Some(value) = value.to_str() {

crates/nu-cli/src/completions/dotnu_completions.rs

@@ -9,6 +9,8 @@ use std::{
     sync::Arc,
 };
 
+use super::SemanticSuggestion;
+
 #[derive(Clone)]
 pub struct DotNuCompletion {
     engine_state: Arc<EngineState>,
@@ -33,7 +35,7 @@ impl Completer for DotNuCompletion {
         offset: usize,
         _: usize,
         options: &CompletionOptions,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         let prefix_str = String::from_utf8_lossy(&prefix).replace('`', "");
         let mut search_dirs: Vec<String> = vec![];
 
@@ -93,7 +95,7 @@ impl Completer for DotNuCompletion {
 
         // Fetch the files filtering the ones that ends with .nu
         // and transform them into suggestions
-        let output: Vec<Suggestion> = search_dirs
+        let output: Vec<SemanticSuggestion> = search_dirs
             .into_iter()
             .flat_map(|search_dir| {
                 let completions = file_path_completion(
@@ -119,7 +121,8 @@ impl Completer for DotNuCompletion {
                             }
                         }
                     })
-                    .map(move |x| Suggestion {
+                    .map(move |x| SemanticSuggestion {
+                        suggestion: Suggestion {
                             value: x.1,
                             description: None,
                             style: x.2,
@@ -129,6 +132,9 @@ impl Completer for DotNuCompletion {
                                 end: x.0.end - offset,
                             },
                             append_whitespace: true,
+                        },
+                        // TODO????
+                        kind: None,
                     })
             })
             .collect();

crates/nu-cli/src/completions/file_completions.rs

@@ -12,6 +12,8 @@ use reedline::Suggestion;
 use std::path::{Path, MAIN_SEPARATOR as SEP};
 use std::sync::Arc;
 
+use super::SemanticSuggestion;
+
 #[derive(Clone)]
 pub struct FileCompletion {
     engine_state: Arc<EngineState>,
@@ -36,7 +38,7 @@ impl Completer for FileCompletion {
         offset: usize,
         _: usize,
         options: &CompletionOptions,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         let AdjustView {
             prefix,
             span,
@@ -53,7 +55,8 @@ impl Completer for FileCompletion {
             &self.stack,
         )
         .into_iter()
-        .map(move |x| Suggestion {
+        .map(move |x| SemanticSuggestion {
+            suggestion: Suggestion {
                 value: x.1,
                 description: None,
                 style: x.2,
@@ -63,6 +66,9 @@ impl Completer for FileCompletion {
                     end: x.0.end - offset,
                 },
                 append_whitespace: false,
+            },
+            // TODO????
+            kind: None,
         })
         .collect();
 
@@ -70,7 +76,7 @@ impl Completer for FileCompletion {
     }
 
     // Sort results prioritizing the non hidden folders
-    fn sort(&self, items: Vec<Suggestion>, prefix: Vec<u8>) -> Vec<Suggestion> {
+    fn sort(&self, items: Vec<SemanticSuggestion>, prefix: Vec<u8>) -> Vec<SemanticSuggestion> {
         let prefix_str = String::from_utf8_lossy(&prefix).to_string();
 
         // Sort items
@@ -80,15 +86,16 @@ impl Completer for FileCompletion {
             SortBy::Ascending => {
                 sorted_items.sort_by(|a, b| {
                     // Ignore trailing slashes in folder names when sorting
-                    a.value
+                    a.suggestion
+                        .value
                         .trim_end_matches(SEP)
-                        .cmp(b.value.trim_end_matches(SEP))
+                        .cmp(b.suggestion.value.trim_end_matches(SEP))
                 });
             }
             SortBy::LevenshteinDistance => {
                 sorted_items.sort_by(|a, b| {
-                    let a_distance = levenshtein_distance(&prefix_str, &a.value);
+                    let a_distance = levenshtein_distance(&prefix_str, &a.suggestion.value);
-                    let b_distance = levenshtein_distance(&prefix_str, &b.value);
+                    let b_distance = levenshtein_distance(&prefix_str, &b.suggestion.value);
                     a_distance.cmp(&b_distance)
                 });
             }
@@ -96,11 +103,11 @@ impl Completer for FileCompletion {
         }
 
         // Separate the results between hidden and non hidden
-        let mut hidden: Vec<Suggestion> = vec![];
+        let mut hidden: Vec<SemanticSuggestion> = vec![];
-        let mut non_hidden: Vec<Suggestion> = vec![];
+        let mut non_hidden: Vec<SemanticSuggestion> = vec![];
 
         for item in sorted_items.into_iter() {
-            let item_path = Path::new(&item.value);
+            let item_path = Path::new(&item.suggestion.value);
 
             if let Some(value) = item_path.file_name() {
                 if let Some(value) = value.to_str() {

crates/nu-cli/src/completions/flag_completions.rs

@@ -7,6 +7,8 @@ use nu_protocol::{
 
 use reedline::Suggestion;
 
+use super::SemanticSuggestion;
+
 #[derive(Clone)]
 pub struct FlagCompletion {
     expression: Expression,
@@ -27,7 +29,7 @@ impl Completer for FlagCompletion {
         offset: usize,
         _: usize,
         options: &CompletionOptions,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         // Check if it's a flag
         if let Expr::Call(call) = &self.expression.expr {
             let decl = working_set.get_decl(call.decl_id);
@@ -43,7 +45,8 @@ impl Completer for FlagCompletion {
                     named.insert(0, b'-');
 
                     if options.match_algorithm.matches_u8(&named, &prefix) {
-                        output.push(Suggestion {
+                        output.push(SemanticSuggestion {
+                            suggestion: Suggestion {
                                 value: String::from_utf8_lossy(&named).to_string(),
                                 description: Some(flag_desc.to_string()),
                                 style: None,
@@ -53,6 +56,9 @@ impl Completer for FlagCompletion {
                                     end: span.end - offset,
                                 },
                                 append_whitespace: true,
+                            },
+                            // TODO????
+                            kind: None,
                         });
                     }
                 }
@@ -66,7 +72,8 @@ impl Completer for FlagCompletion {
                 named.insert(0, b'-');
 
                 if options.match_algorithm.matches_u8(&named, &prefix) {
-                    output.push(Suggestion {
+                    output.push(SemanticSuggestion {
+                        suggestion: Suggestion {
                             value: String::from_utf8_lossy(&named).to_string(),
                             description: Some(flag_desc.to_string()),
                             style: None,
@@ -76,6 +83,9 @@ impl Completer for FlagCompletion {
                                 end: span.end - offset,
                             },
                             append_whitespace: true,
+                        },
+                        // TODO????
+                        kind: None,
                     });
                 }
             }

crates/nu-cli/src/completions/mod.rs

@@ -10,7 +10,7 @@ mod file_completions;
 mod flag_completions;
 mod variable_completions;
 
-pub use base::Completer;
+pub use base::{Completer, SemanticSuggestion, SuggestionKind};
 pub use command_completions::CommandCompletion;
 pub use completer::NuCompleter;
 pub use completion_options::{CompletionOptions, MatchAlgorithm, SortBy};

crates/nu-cli/src/completions/variable_completions.rs

@@ -9,7 +9,7 @@ use reedline::Suggestion;
 use std::str;
 use std::sync::Arc;
 
-use super::MatchAlgorithm;
+use super::{MatchAlgorithm, SemanticSuggestion, SuggestionKind};
 
 #[derive(Clone)]
 pub struct VariableCompletion {
@@ -41,7 +41,7 @@ impl Completer for VariableCompletion {
         offset: usize,
         _: usize,
         options: &CompletionOptions,
-    ) -> Vec<Suggestion> {
+    ) -> Vec<SemanticSuggestion> {
         let mut output = vec![];
         let builtins = ["$nu", "$in", "$env"];
         let var_str = std::str::from_utf8(&self.var_context.0).unwrap_or("");
@@ -75,7 +75,7 @@ impl Completer for VariableCompletion {
                         {
                             if options.match_algorithm.matches_u8_insensitive(
                                 options.case_sensitive,
-                                suggestion.value.as_bytes(),
+                                suggestion.suggestion.value.as_bytes(),
                                 &prefix,
                             ) {
                                 output.push(suggestion);
@@ -92,13 +92,16 @@ impl Completer for VariableCompletion {
                             env_var.0.as_bytes(),
                             &prefix,
                         ) {
-                            output.push(Suggestion {
+                            output.push(SemanticSuggestion {
+                                suggestion: Suggestion {
                                     value: env_var.0,
                                     description: None,
                                     style: None,
                                     extra: None,
                                     span: current_span,
                                     append_whitespace: false,
+                                },
+                                kind: Some(SuggestionKind::Type(env_var.1.get_type())),
                             });
                         }
                     }
@@ -121,7 +124,7 @@ impl Completer for VariableCompletion {
                     {
                         if options.match_algorithm.matches_u8_insensitive(
                             options.case_sensitive,
-                            suggestion.value.as_bytes(),
+                            suggestion.suggestion.value.as_bytes(),
                             &prefix,
                         ) {
                             output.push(suggestion);
@@ -144,7 +147,7 @@ impl Completer for VariableCompletion {
                     {
                         if options.match_algorithm.matches_u8_insensitive(
                             options.case_sensitive,
-                            suggestion.value.as_bytes(),
+                            suggestion.suggestion.value.as_bytes(),
                             &prefix,
                         ) {
                             output.push(suggestion);
@@ -163,13 +166,17 @@ impl Completer for VariableCompletion {
                 builtin.as_bytes(),
                 &prefix,
             ) {
-                output.push(Suggestion {
+                output.push(SemanticSuggestion {
+                    suggestion: Suggestion {
                         value: builtin.to_string(),
                         description: None,
                         style: None,
                         extra: None,
                         span: current_span,
                         append_whitespace: false,
+                    },
+                    // TODO is there a way to get the VarId to get the type???
+                    kind: None,
                 });
             }
         }
@@ -186,13 +193,18 @@ impl Completer for VariableCompletion {
                         v.0,
                         &prefix,
                     ) {
-                        output.push(Suggestion {
+                        output.push(SemanticSuggestion {
+                            suggestion: Suggestion {
                                 value: String::from_utf8_lossy(v.0).to_string(),
                                 description: None,
                                 style: None,
                                 extra: None,
                                 span: current_span,
                                 append_whitespace: false,
+                            },
+                            kind: Some(SuggestionKind::Type(
+                                working_set.get_variable(*v.1).ty.clone(),
+                            )),
                         });
                     }
                 }
@@ -208,13 +220,18 @@ impl Completer for VariableCompletion {
                     v.0,
                     &prefix,
                 ) {
-                    output.push(Suggestion {
+                    output.push(SemanticSuggestion {
+                        suggestion: Suggestion {
                             value: String::from_utf8_lossy(v.0).to_string(),
                             description: None,
                             style: None,
                             extra: None,
                             span: current_span,
                             append_whitespace: false,
+                        },
+                        kind: Some(SuggestionKind::Type(
+                            working_set.get_variable(*v.1).ty.clone(),
+                        )),
                     });
                 }
             }
@@ -232,21 +249,25 @@ fn nested_suggestions(
     val: Value,
     sublevels: Vec<Vec<u8>>,
     current_span: reedline::Span,
-) -> Vec<Suggestion> {
+) -> Vec<SemanticSuggestion> {
-    let mut output: Vec<Suggestion> = vec![];
+    let mut output: Vec<SemanticSuggestion> = vec![];
     let value = recursive_value(val, sublevels);
 
+    let kind = SuggestionKind::Type(value.get_type());
     match value {
         Value::Record { val, .. } => {
             // Add all the columns as completion
             for (col, _) in val.into_iter() {
-                output.push(Suggestion {
+                output.push(SemanticSuggestion {
+                    suggestion: Suggestion {
                         value: col,
                         description: None,
                         style: None,
                         extra: None,
                         span: current_span,
                         append_whitespace: false,
+                    },
+                    kind: Some(kind.clone()),
                 });
             }
 
@@ -255,13 +276,16 @@ fn nested_suggestions(
         Value::LazyRecord { val, .. } => {
             // Add all the columns as completion
             for column_name in val.column_names() {
-                output.push(Suggestion {
+                output.push(SemanticSuggestion {
+                    suggestion: Suggestion {
                         value: column_name.to_string(),
                         description: None,
                         style: None,
                         extra: None,
                         span: current_span,
                         append_whitespace: false,
+                    },
+                    kind: Some(kind.clone()),
                 });
             }
 
@@ -269,13 +293,16 @@ fn nested_suggestions(
         }
         Value::List { vals, .. } => {
             for column_name in get_columns(vals.as_slice()) {
-                output.push(Suggestion {
+                output.push(SemanticSuggestion {
+                    suggestion: Suggestion {
                         value: column_name,
                         description: None,
                         style: None,
                         extra: None,
                         span: current_span,
                         append_whitespace: false,
+                    },
+                    kind: Some(kind.clone()),
                 });
             }
 

crates/nu-cli/src/lib.rs

@@ -15,7 +15,7 @@ mod util;
 mod validation;
 
 pub use commands::add_cli_context;
-pub use completions::{FileCompletion, NuCompleter};
+pub use completions::{FileCompletion, NuCompleter, SemanticSuggestion, SuggestionKind};
 pub use config_files::eval_config_contents;
 pub use eval_cmds::evaluate_commands;
 pub use eval_file::evaluate_file;

crates/nu-lsp/src/lib.rs

@@ -11,18 +11,18 @@ use std::{
 use lsp_server::{Connection, IoThreads, Message, Response, ResponseError};
 use lsp_types::{
     request::{Completion, GotoDefinition, HoverRequest, Request},
-    CompletionItem, CompletionParams, CompletionResponse, CompletionTextEdit, GotoDefinitionParams,
+    CompletionItem, CompletionItemKind, CompletionParams, CompletionResponse, CompletionTextEdit,
-    GotoDefinitionResponse, Hover, HoverContents, HoverParams, Location, MarkupContent, MarkupKind,
+    GotoDefinitionParams, GotoDefinitionResponse, Hover, HoverContents, HoverParams, Location,
-    OneOf, Range, ServerCapabilities, TextDocumentSyncKind, TextEdit, Url,
+    MarkupContent, MarkupKind, OneOf, Range, ServerCapabilities, TextDocumentSyncKind, TextEdit,
+    Url,
 };
 use miette::{IntoDiagnostic, Result};
-use nu_cli::NuCompleter;
+use nu_cli::{NuCompleter, SuggestionKind};
 use nu_parser::{flatten_block, parse, FlatShape};
 use nu_protocol::{
     engine::{EngineState, Stack, StateWorkingSet},
     DeclId, Span, Value, VarId,
 };
-use reedline::Completer;
 use ropey::Rope;
 
 mod diagnostics;
@@ -559,7 +559,8 @@ impl LanguageServer {
 
         let location =
             Self::lsp_position_to_location(&params.text_document_position.position, rope_of_file);
-        let results = completer.complete(&rope_of_file.to_string()[..location], location);
+        let results =
+            completer.fetch_completions_at(&rope_of_file.to_string()[..location], location);
         if results.is_empty() {
             None
         } else {
@@ -568,17 +569,18 @@ impl LanguageServer {
                     .into_iter()
                     .map(|r| {
                         let mut start = params.text_document_position.position;
-                        start.character -= (r.span.end - r.span.start) as u32;
+                        start.character -= (r.suggestion.span.end - r.suggestion.span.start) as u32;
 
                         CompletionItem {
-                            label: r.value.clone(),
+                            label: r.suggestion.value.clone(),
-                            detail: r.description,
+                            detail: r.suggestion.description,
+                            kind: Self::lsp_completion_item_kind(r.kind),
                             text_edit: Some(CompletionTextEdit::Edit(TextEdit {
                                 range: Range {
                                     start,
                                     end: params.text_document_position.position,
                                 },
-                                new_text: r.value,
+                                new_text: r.suggestion.value,
                             })),
                             ..Default::default()
                         }
@@ -587,12 +589,28 @@ impl LanguageServer {
             ))
         }
     }
+
+    fn lsp_completion_item_kind(
+        suggestion_kind: Option<SuggestionKind>,
+    ) -> Option<CompletionItemKind> {
+        suggestion_kind.and_then(|suggestion_kind| match suggestion_kind {
+            SuggestionKind::Type(t) => match t {
+                nu_protocol::Type::String => Some(CompletionItemKind::VARIABLE),
+                _ => None,
+            },
+            SuggestionKind::Command(c) => match c {
+                nu_protocol::engine::CommandType::Keyword => Some(CompletionItemKind::KEYWORD),
+                nu_protocol::engine::CommandType::Builtin => Some(CompletionItemKind::FUNCTION),
+                _ => None,
+            },
+        })
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
-    use assert_json_diff::assert_json_eq;
+    use assert_json_diff::{assert_json_eq, assert_json_include};
     use lsp_types::{
         notification::{
             DidChangeTextDocument, DidOpenTextDocument, Exit, Initialized, Notification,
@@ -1078,7 +1096,8 @@ mod tests {
                         "start": { "character": 5, "line": 2 },
                         "end": { "character": 9, "line": 2 }
                      }
-                  }
+                  },
+                  "kind": 6
                }
             ])
         );
@@ -1115,7 +1134,8 @@ mod tests {
                         "end": { "line": 0, "character": 8 },
                      },
                      "newText": "config nu"
-                  }
+                  },
+                  "kind": 3
                }
             ])
         );
@@ -1152,7 +1172,45 @@ mod tests {
                         "end": { "line": 0, "character": 14 },
                      },
                      "newText": "str trim"
+                  },
+                  "kind": 3
                }
+            ])
+        );
+    }
+
+    #[test]
+    fn complete_keyword() {
+        let (client_connection, _recv) = initialize_language_server();
+
+        let mut script = fixtures();
+        script.push("lsp");
+        script.push("completion");
+        script.push("keyword.nu");
+        let script = Url::from_file_path(script).unwrap();
+
+        open_unchecked(&client_connection, script.clone());
+
+        let resp = complete(&client_connection, script, 0, 2);
+        let result = if let Message::Response(response) = resp {
+            response.result
+        } else {
+            panic!()
+        };
+
+        assert_json_include!(
+            actual: result,
+            expected: serde_json::json!([
+               {
+                  "label": "def",
+                  "textEdit": {
+                     "newText": "def",
+                     "range": {
+                        "start": { "character": 0, "line": 0 },
+                        "end": { "character": 2, "line": 0 }
+                     }
+                  },
+                  "kind": 14
                }
             ])
         );

crates/nu-protocol/src/engine/command.rs

@@ -2,7 +2,7 @@ use crate::{ast::Call, Alias, BlockId, Example, IoStream, PipelineData, ShellErr
 
 use super::{EngineState, Stack, StateWorkingSet};
 
-#[derive(Debug)]
+#[derive(Clone, Debug, PartialEq)]
 pub enum CommandType {
     Builtin,
     Custom,

crates/nu-protocol/src/engine/engine_state.rs

@@ -4,7 +4,8 @@ use lru::LruCache;
 use super::cached_file::CachedFile;
 use super::{usage::build_usage, usage::Usage, StateDelta};
 use super::{
-    Command, EnvVars, OverlayFrame, ScopeFrame, Stack, Variable, Visibility, DEFAULT_OVERLAY_NAME,
+    Command, CommandType, EnvVars, OverlayFrame, ScopeFrame, Stack, Variable, Visibility,
+    DEFAULT_OVERLAY_NAME,
 };
 use crate::ast::Block;
 use crate::debugger::{Debugger, NoopDebugger};
@@ -733,7 +734,7 @@ impl EngineState {
         &self,
         predicate: impl Fn(&[u8]) -> bool,
         ignore_deprecated: bool,
-    ) -> Vec<(Vec<u8>, Option<String>)> {
+    ) -> Vec<(Vec<u8>, Option<String>, CommandType)> {
         let mut output = vec![];
 
         for overlay_frame in self.active_overlays(&[]).rev() {
@@ -743,7 +744,11 @@ impl EngineState {
                     if ignore_deprecated && command.signature().category == Category::Removed {
                         continue;
                     }
-                    output.push((decl.0.clone(), Some(command.usage().to_string())));
+                    output.push((
+                        decl.0.clone(),
+                        Some(command.usage().to_string()),
+                        command.command_type(),
+                    ));
                 }
             }
         }

crates/nu-protocol/src/engine/state_working_set.rs

@@ -1,4 +1,5 @@
 use super::cached_file::CachedFile;
+use super::CommandType;
 use super::{
     usage::build_usage, Command, EngineState, OverlayFrame, StateDelta, Variable, VirtualPath,
     Visibility, PWD_ENV,
@@ -708,7 +709,7 @@ impl<'a> StateWorkingSet<'a> {
         &self,
         predicate: impl Fn(&[u8]) -> bool,
         ignore_deprecated: bool,
-    ) -> Vec<(Vec<u8>, Option<String>)> {
+    ) -> Vec<(Vec<u8>, Option<String>, CommandType)> {
         let mut output = vec![];
 
         for scope_frame in self.delta.scope.iter().rev() {
@@ -721,7 +722,11 @@ impl<'a> StateWorkingSet<'a> {
                         if ignore_deprecated && command.signature().category == Category::Removed {
                             continue;
                         }
-                        output.push((decl.0.clone(), Some(command.usage().to_string())));
+                        output.push((
+                            decl.0.clone(),
+                            Some(command.usage().to_string()),
+                            command.command_type(),
+                        ));
                     }
                 }
             }

tests/fixtures/lsp/completion/keyword.nu

@@ -0,0 +1 @@
+de