Merge #3954

3954: Improve autocompletion by looking on the type and name r=matklad a=bnjjj

This tweet (https://twitter.com/tjholowaychuk/status/1248918374731714560) gaves me the idea to implement that in rust-analyzer.

Basically for this first example I made some examples when we are in a function call definition. I look on the parameter list to prioritize autocompletions for the same types and if it's the same type + the same name then it's displayed first in the completion list.

So here is a draft, first step to open a discussion and know what you think about the implementation. It works (cf tests) but maybe I can make a better implementation at some places. Be careful the code needs some refactoring to be better and concise.

PS: It was lot of fun writing this haha

Co-authored-by: Benjamin Coenen <[email protected]>

7 files changed, 388 insertions, 28 deletions

diff --git a/crates/ra_ide/src/completion.rs b/crates/ra_ide/src/completion.rs
index 4a1a2a04a..19bc4321c 100644
--- a/crates/ra_ide/src/completion.rs
+++ b/crates/ra_ide/src/completion.rs
@@ -29,7 +29,7 @@ use crate::{
 };
 
 pub use crate::completion::completion_item::{
-    CompletionItem, CompletionItemKind, InsertTextFormat,
+    CompletionItem, CompletionItemKind, CompletionScore, InsertTextFormat,
 };
 
 #[derive(Clone, Debug, PartialEq, Eq)]
diff --git a/crates/ra_ide/src/completion/complete_dot.rs b/crates/ra_ide/src/completion/complete_dot.rs
index f433faef3..44288f92e 100644
--- a/crates/ra_ide/src/completion/complete_dot.rs
+++ b/crates/ra_ide/src/completion/complete_dot.rs
@@ -2,9 +2,11 @@
 
 use hir::{HasVisibility, Type};
 
-use crate::completion::completion_item::CompletionKind;
 use crate::{
-    completion::{completion_context::CompletionContext, completion_item::Completions},
+    completion::{
+        completion_context::CompletionContext,
+        completion_item::{CompletionKind, Completions},
+    },
     CompletionItem,
 };
 use rustc_hash::FxHashSet;
@@ -104,6 +106,237 @@ mod tests {
     }
 
     #[test]
+    fn test_struct_field_completion_in_func_call() {
+        assert_debug_snapshot!(
+        do_ref_completion(
+                r"
+                struct A { another_field: i64, the_field: u32, my_string: String }
+                fn test(my_param: u32) -> u32 { my_param }
+                fn foo(a: A) {
+                    test(a.<|>)
+                }
+                ",
+        ),
+            @r###"
+        [
+            CompletionItem {
+                label: "another_field",
+                source_range: [201; 201),
+                delete: [201; 201),
+                insert: "another_field",
+                kind: Field,
+                detail: "i64",
+            },
+            CompletionItem {
+                label: "my_string",
+                source_range: [201; 201),
+                delete: [201; 201),
+                insert: "my_string",
+                kind: Field,
+                detail: "{unknown}",
+            },
+            CompletionItem {
+                label: "the_field",
+                source_range: [201; 201),
+                delete: [201; 201),
+                insert: "the_field",
+                kind: Field,
+                detail: "u32",
+                score: TypeMatch,
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
+    fn test_struct_field_completion_in_func_call_with_type_and_name() {
+        assert_debug_snapshot!(
+        do_ref_completion(
+                r"
+                struct A { another_field: i64, another_good_type: u32, the_field: u32 }
+                fn test(the_field: u32) -> u32 { the_field }
+                fn foo(a: A) {
+                    test(a.<|>)
+                }
+                ",
+        ),
+            @r###"
+        [
+            CompletionItem {
+                label: "another_field",
+                source_range: [208; 208),
+                delete: [208; 208),
+                insert: "another_field",
+                kind: Field,
+                detail: "i64",
+            },
+            CompletionItem {
+                label: "another_good_type",
+                source_range: [208; 208),
+                delete: [208; 208),
+                insert: "another_good_type",
+                kind: Field,
+                detail: "u32",
+                score: TypeMatch,
+            },
+            CompletionItem {
+                label: "the_field",
+                source_range: [208; 208),
+                delete: [208; 208),
+                insert: "the_field",
+                kind: Field,
+                detail: "u32",
+                score: TypeAndNameMatch,
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
+    fn test_struct_field_completion_in_record_lit() {
+        assert_debug_snapshot!(
+        do_ref_completion(
+                r"
+                struct A { another_field: i64, another_good_type: u32, the_field: u32 }
+                struct B { my_string: String, my_vec: Vec<u32>, the_field: u32 }
+                fn foo(a: A) {
+                    let b = B {
+                        the_field: a.<|>
+                    };
+                }
+                ",
+        ),
+            @r###"
+        [
+            CompletionItem {
+                label: "another_field",
+                source_range: [270; 270),
+                delete: [270; 270),
+                insert: "another_field",
+                kind: Field,
+                detail: "i64",
+            },
+            CompletionItem {
+                label: "another_good_type",
+                source_range: [270; 270),
+                delete: [270; 270),
+                insert: "another_good_type",
+                kind: Field,
+                detail: "u32",
+                score: TypeMatch,
+            },
+            CompletionItem {
+                label: "the_field",
+                source_range: [270; 270),
+                delete: [270; 270),
+                insert: "the_field",
+                kind: Field,
+                detail: "u32",
+                score: TypeAndNameMatch,
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
+    fn test_struct_field_completion_in_record_lit_and_fn_call() {
+        assert_debug_snapshot!(
+        do_ref_completion(
+                r"
+                struct A { another_field: i64, another_good_type: u32, the_field: u32 }
+                struct B { my_string: String, my_vec: Vec<u32>, the_field: u32 }
+                fn test(the_field: i64) -> i64 { the_field }
+                fn foo(a: A) {
+                    let b = B {
+                        the_field: test(a.<|>)
+                    };
+                }
+                ",
+        ),
+            @r###"
+        [
+            CompletionItem {
+                label: "another_field",
+                source_range: [336; 336),
+                delete: [336; 336),
+                insert: "another_field",
+                kind: Field,
+                detail: "i64",
+                score: TypeMatch,
+            },
+            CompletionItem {
+                label: "another_good_type",
+                source_range: [336; 336),
+                delete: [336; 336),
+                insert: "another_good_type",
+                kind: Field,
+                detail: "u32",
+            },
+            CompletionItem {
+                label: "the_field",
+                source_range: [336; 336),
+                delete: [336; 336),
+                insert: "the_field",
+                kind: Field,
+                detail: "u32",
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
+    fn test_struct_field_completion_in_fn_call_and_record_lit() {
+        assert_debug_snapshot!(
+        do_ref_completion(
+                r"
+                struct A { another_field: i64, another_good_type: u32, the_field: u32 }
+                struct B { my_string: String, my_vec: Vec<u32>, the_field: u32 }
+                fn test(the_field: i64) -> i64 { the_field }
+                fn foo(a: A) {
+                    test(B {
+                        the_field: a.<|>
+                    });
+                }
+                ",
+        ),
+            @r###"
+        [
+            CompletionItem {
+                label: "another_field",
+                source_range: [328; 328),
+                delete: [328; 328),
+                insert: "another_field",
+                kind: Field,
+                detail: "i64",
+            },
+            CompletionItem {
+                label: "another_good_type",
+                source_range: [328; 328),
+                delete: [328; 328),
+                insert: "another_good_type",
+                kind: Field,
+                detail: "u32",
+                score: TypeMatch,
+            },
+            CompletionItem {
+                label: "the_field",
+                source_range: [328; 328),
+                delete: [328; 328),
+                insert: "the_field",
+                kind: Field,
+                detail: "u32",
+                score: TypeAndNameMatch,
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
     fn test_struct_field_completion_self() {
         assert_debug_snapshot!(
         do_ref_completion(
diff --git a/crates/ra_ide/src/completion/completion_context.rs b/crates/ra_ide/src/completion/completion_context.rs
index cfc5c34df..dd7c8a873 100644
--- a/crates/ra_ide/src/completion/completion_context.rs
+++ b/crates/ra_ide/src/completion/completion_context.rs
@@ -21,6 +21,7 @@ pub(crate) struct CompletionContext<'a> {
     pub(super) db: &'a RootDatabase,
     pub(super) config: &'a CompletionConfig,
     pub(super) offset: TextUnit,
+    pub(super) file_position: FilePosition,
     /// The token before the cursor, in the original file.
     pub(super) original_token: SyntaxToken,
     /// The token before the cursor, in the macro-expanded file.
@@ -31,6 +32,7 @@ pub(crate) struct CompletionContext<'a> {
     pub(super) use_item_syntax: Option<ast::UseItem>,
     pub(super) record_lit_syntax: Option<ast::RecordLit>,
     pub(super) record_pat_syntax: Option<ast::RecordPat>,
+    pub(super) record_field_syntax: Option<ast::RecordField>,
     pub(super) impl_def: Option<ast::ImplDef>,
     pub(super) is_param: bool,
     /// If a name-binding or reference to a const in a pattern.
@@ -88,12 +90,14 @@ impl<'a> CompletionContext<'a> {
             original_token,
             token,
             offset: position.offset,
+            file_position: position,
             krate,
             name_ref_syntax: None,
             function_syntax: None,
             use_item_syntax: None,
             record_lit_syntax: None,
             record_pat_syntax: None,
+            record_field_syntax: None,
             impl_def: None,
             is_param: false,
             is_pat_binding_or_const: false,
@@ -279,6 +283,14 @@ impl<'a> CompletionContext<'a> {
             .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
             .find_map(ast::FnDef::cast);
 
+        self.record_field_syntax = self
+            .sema
+            .ancestors_with_macros(self.token.parent())
+            .take_while(|it| {
+                it.kind() != SOURCE_FILE && it.kind() != MODULE && it.kind() != CALL_EXPR
+            })
+            .find_map(ast::RecordField::cast);
+
         let parent = match name_ref.syntax().parent() {
             Some(it) => it,
             None => return,
diff --git a/crates/ra_ide/src/completion/completion_item.rs b/crates/ra_ide/src/completion/completion_item.rs
index bc0f1aff5..e17586aa5 100644
--- a/crates/ra_ide/src/completion/completion_item.rs
+++ b/crates/ra_ide/src/completion/completion_item.rs
@@ -51,6 +51,9 @@ pub struct CompletionItem {
     /// If completing a function call, ask the editor to show parameter popup
     /// after completion.
     trigger_call_info: bool,
+
+    /// Score is usefull to pre select or display in better order completion items
+    score: Option<CompletionScore>,
 }
 
 // We use custom debug for CompletionItem to make `insta`'s diffs more readable.
@@ -80,6 +83,9 @@ impl fmt::Debug for CompletionItem {
         if self.deprecated {
             s.field("deprecated", &true);
         }
+        if let Some(score) = &self.score {
+            s.field("score", score);
+        }
         if self.trigger_call_info {
             s.field("trigger_call_info", &true);
         }
@@ -147,6 +153,7 @@ impl CompletionItem {
             text_edit: None,
             deprecated: None,
             trigger_call_info: None,
+            score: None,
         }
     }
     /// What user sees in pop-up in the UI.
@@ -186,6 +193,14 @@ impl CompletionItem {
         self.deprecated
     }
 
+    pub fn score(&self) -> Option<CompletionScore> {
+        self.score.clone()
+    }
+
+    pub fn set_score(&mut self, score: CompletionScore) {
+        self.score = Some(score);
+    }
+
     pub fn trigger_call_info(&self) -> bool {
         self.trigger_call_info
     }
@@ -206,6 +221,7 @@ pub(crate) struct Builder {
     text_edit: Option<TextEdit>,
     deprecated: Option<bool>,
     trigger_call_info: Option<bool>,
+    score: Option<CompletionScore>,
 }
 
 impl Builder {
@@ -235,6 +251,7 @@ impl Builder {
             completion_kind: self.completion_kind,
             deprecated: self.deprecated.unwrap_or(false),
             trigger_call_info: self.trigger_call_info.unwrap_or(false),
+            score: self.score,
         }
     }
     pub(crate) fn lookup_by(mut self, lookup: impl Into<String>) -> Builder {
@@ -285,6 +302,11 @@ impl Builder {
         self.deprecated = Some(deprecated);
         self
     }
+    #[allow(unused)]
+    pub(crate) fn set_score(mut self, score: CompletionScore) -> Builder {
+        self.score = Some(score);
+        self
+    }
     pub(crate) fn trigger_call_info(mut self) -> Builder {
         self.trigger_call_info = Some(true);
         self
@@ -297,6 +319,14 @@ impl<'a> Into<CompletionItem> for Builder {
     }
 }
 
+#[derive(Debug, Clone)]
+pub enum CompletionScore {
+    /// If only type match
+    TypeMatch,
+    /// If type and name match
+    TypeAndNameMatch,
+}
+
 /// Represents an in-progress set of completions being built.
 #[derive(Debug, Default)]
 pub(crate) struct Completions {
diff --git a/crates/ra_ide/src/completion/presentation.rs b/crates/ra_ide/src/completion/presentation.rs
index 2189cef65..f8dac1d54 100644
--- a/crates/ra_ide/src/completion/presentation.rs
+++ b/crates/ra_ide/src/completion/presentation.rs
@@ -6,12 +6,13 @@ use stdx::SepBy;
 use test_utils::tested_by;
 
 use crate::{
+    call_info::call_info,
     completion::{
         completion_item::Builder, CompletionContext, CompletionItem, CompletionItemKind,
         CompletionKind, Completions,
     },
     display::{const_label, macro_label, type_label, FunctionSignature},
-    RootDatabase,
+    CompletionScore, RootDatabase,
 };
 
 impl Completions {
@@ -22,7 +23,7 @@ impl Completions {
         ty: &Type,
     ) {
         let is_deprecated = is_deprecated(field, ctx.db);
-        CompletionItem::new(
+        let mut completion_item = CompletionItem::new(
             CompletionKind::Reference,
             ctx.source_range(),
             field.name(ctx.db).to_string(),
@@ -31,7 +32,11 @@ impl Completions {
         .detail(ty.display(ctx.db).to_string())
         .set_documentation(field.docs(ctx.db))
         .set_deprecated(is_deprecated)
-        .add_to(self);
+        .build();
+
+        compute_score(&mut completion_item, ctx);
+
+        self.add(completion_item);
     }
 
     pub(crate) fn add_tuple_field(&mut self, ctx: &CompletionContext, field: usize, ty: &Type) {
@@ -300,6 +305,42 @@ impl Completions {
     }
 }
 
+pub(crate) fn compute_score(completion_item: &mut CompletionItem, ctx: &CompletionContext) {
+    let (active_name, active_type) = if let Some(record_field) = &ctx.record_field_syntax {
+        if let Some((struct_field, _)) = ctx.sema.resolve_record_field(record_field) {
+            (
+                struct_field.name(ctx.db).to_string(),
+                struct_field.signature_ty(ctx.db).display(ctx.db).to_string(),
+            )
+        } else {
+            return;
+        }
+    } else if let Some(call_info) = call_info(ctx.db, ctx.file_position) {
+        if call_info.active_parameter_type().is_some()
+            && call_info.active_parameter_name().is_some()
+        {
+            (call_info.active_parameter_name().unwrap(), call_info.active_parameter_type().unwrap())
+        } else {
+            return;
+        }
+    } else {
+        return;
+    };
+
+    // Compute score
+    // For the same type
+    if let Some(a_parameter_type) = completion_item.detail() {
+        if &active_type == a_parameter_type {
+            // If same type + same name then go top position
+            if active_name == completion_item.label() {
+                completion_item.set_score(CompletionScore::TypeAndNameMatch);
+            } else {
+                completion_item.set_score(CompletionScore::TypeMatch);
+            }
+        }
+    }
+}
+
 enum Params {
     Named(Vec<String>),
     Anonymous(usize),
diff --git a/crates/ra_ide/src/display/function_signature.rs b/crates/ra_ide/src/display/function_signature.rs
index b967a6816..b5e2785fe 100644
--- a/crates/ra_ide/src/display/function_signature.rs
+++ b/crates/ra_ide/src/display/function_signature.rs
@@ -36,6 +36,8 @@ pub struct FunctionSignature {
     pub parameters: Vec<String>,
     /// Parameter names of the function
     pub parameter_names: Vec<String>,
+    /// Parameter types of the function
+    pub parameter_types: Vec<String>,
     /// Optional return type
     pub ret_type: Option<String>,
     /// Where predicates
@@ -62,14 +64,20 @@ impl FunctionSignature {
             return None;
         };
 
-        let params = st
-            .fields(db)
-            .into_iter()
-            .map(|field: hir::StructField| {
-                let ty = field.signature_ty(db);
-                format!("{}", ty.display(db))
-            })
-            .collect();
+        let mut params = vec![];
+        let mut parameter_types = vec![];
+        for field in st.fields(db).into_iter() {
+            let ty = field.signature_ty(db);
+            let raw_param = format!("{}", ty.display(db));
+
+            if let Some(param_type) = raw_param.split(':').nth(1) {
+                parameter_types.push(param_type[1..].to_string());
+            } else {
+                // useful when you have tuple struct
+                parameter_types.push(raw_param.clone());
+            }
+            params.push(raw_param);
+        }
 
         Some(
             FunctionSignature {
@@ -79,6 +87,7 @@ impl FunctionSignature {
                 ret_type: node.name().map(|n| n.text().to_string()),
                 parameters: params,
                 parameter_names: vec![],
+                parameter_types,
                 generic_parameters: generic_parameters(&node),
                 where_predicates: where_predicates(&node),
                 doc: None,
@@ -99,15 +108,21 @@ impl FunctionSignature {
 
         let name = format!("{}::{}", parent_name, variant.name(db));
 
-        let params = variant
-            .fields(db)
-            .into_iter()
-            .map(|field: hir::StructField| {
-                let name = field.name(db);
-                let ty = field.signature_ty(db);
-                format!("{}: {}", name, ty.display(db))
-            })
-            .collect();
+        let mut params = vec![];
+        let mut parameter_types = vec![];
+        for field in variant.fields(db).into_iter() {
+            let ty = field.signature_ty(db);
+            let raw_param = format!("{}", ty.display(db));
+            if let Some(param_type) = raw_param.split(':').nth(1) {
+                parameter_types.push(param_type[1..].to_string());
+            } else {
+                // The unwrap_or_else is useful when you have tuple
+                parameter_types.push(raw_param);
+            }
+            let name = field.name(db);
+
+            params.push(format!("{}: {}", name, ty.display(db)));
+        }
 
         Some(
             FunctionSignature {
@@ -117,6 +132,7 @@ impl FunctionSignature {
                 ret_type: None,
                 parameters: params,
                 parameter_names: vec![],
+                parameter_types,
                 generic_parameters: vec![],
                 where_predicates: vec![],
                 doc: None,
@@ -139,6 +155,7 @@ impl FunctionSignature {
                 ret_type: None,
                 parameters: params,
                 parameter_names: vec![],
+                parameter_types: vec![],
                 generic_parameters: vec![],
                 where_predicates: vec![],
                 doc: None,
@@ -151,18 +168,27 @@ impl FunctionSignature {
 
 impl From<&'_ ast::FnDef> for FunctionSignature {
     fn from(node: &ast::FnDef) -> FunctionSignature {
-        fn param_list(node: &ast::FnDef) -> (bool, Vec<String>) {
+        fn param_list(node: &ast::FnDef) -> (bool, Vec<String>, Vec<String>) {
             let mut res = vec![];
+            let mut res_types = vec![];
             let mut has_self_param = false;
             if let Some(param_list) = node.param_list() {
                 if let Some(self_param) = param_list.self_param() {
                     has_self_param = true;
-                    res.push(self_param.syntax().text().to_string())
+                    let raw_param = self_param.syntax().text().to_string();
+
+                    res_types.push(
+                        raw_param.split(':').nth(1).unwrap_or_else(|| " Self")[1..].to_string(),
+                    );
+                    res.push(raw_param);
                 }
 
                 res.extend(param_list.params().map(|param| param.syntax().text().to_string()));
+                res_types.extend(param_list.params().map(|param| {
+                    param.syntax().text().to_string().split(':').nth(1).unwrap()[1..].to_string()
+                }));
             }
-            (has_self_param, res)
+            (has_self_param, res, res_types)
         }
 
         fn param_name_list(node: &ast::FnDef) -> Vec<String> {
@@ -192,7 +218,7 @@ impl From<&'_ ast::FnDef> for FunctionSignature {
             res
         }
 
-        let (has_self_param, parameters) = param_list(node);
+        let (has_self_param, parameters, parameter_types) = param_list(node);
 
         FunctionSignature {
             kind: CallableKind::Function,
@@ -204,6 +230,7 @@ impl From<&'_ ast::FnDef> for FunctionSignature {
                 .map(|n| n.syntax().text().to_string()),
             parameters,
             parameter_names: param_name_list(node),
+            parameter_types,
             generic_parameters: generic_parameters(node),
             where_predicates: where_predicates(node),
             // docs are processed separately
diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index 5599f143f..ddaa30a16 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -67,7 +67,9 @@ use crate::display::ToNav;
 pub use crate::{
     assists::{Assist, AssistId},
     call_hierarchy::CallItem,
-    completion::{CompletionConfig, CompletionItem, CompletionItemKind, InsertTextFormat},
+    completion::{
+        CompletionConfig, CompletionItem, CompletionItemKind, CompletionScore, InsertTextFormat,
+    },
     diagnostics::Severity,
     display::{file_structure, FunctionSignature, NavigationTarget, StructureNode},
     expand_macro::ExpandedMacro,
@@ -127,6 +129,21 @@ pub struct CallInfo {
     pub active_parameter: Option<usize>,
 }
 
+impl CallInfo {
+    pub fn active_parameter_type(&self) -> Option<String> {
+        if let Some(id) = self.active_parameter {
+            return self.signature.parameter_types.get(id).map(|param_ty| param_ty.clone());
+        }
+        None
+    }
+    pub fn active_parameter_name(&self) -> Option<String> {
+        if let Some(id) = self.active_parameter {
+            return self.signature.parameter_names.get(id).map(|param_ty| param_ty.clone());
+        }
+        None
+    }
+}
+
 /// `AnalysisHost` stores the current state of the world.
 #[derive(Debug)]
 pub struct AnalysisHost {