7 files changed, 116 insertions, 79 deletions

diff --git a/crates/completion/src/completions.rs b/crates/completion/src/completions.rs
index 75dbb1a23..9b7d6c580 100644
--- a/crates/completion/src/completions.rs
+++ b/crates/completion/src/completions.rs
@@ -90,7 +90,7 @@ impl Completions {
             Some(it) => it,
             None => return,
         };
-        if let Some(item) = render_macro(RenderContext::new(ctx), name, macro_) {
+        if let Some(item) = render_macro(RenderContext::new(ctx), None, name, macro_) {
             self.add(item);
         }
     }
@@ -101,7 +101,7 @@ impl Completions {
         func: hir::Function,
         local_name: Option<String>,
     ) {
-        let item = render_fn(RenderContext::new(ctx), local_name, func);
+        let item = render_fn(RenderContext::new(ctx), None, local_name, func);
         self.add(item)
     }
 
@@ -123,7 +123,7 @@ impl Completions {
         variant: hir::EnumVariant,
         path: ModPath,
     ) {
-        let item = render_enum_variant(RenderContext::new(ctx), None, variant, Some(path));
+        let item = render_enum_variant(RenderContext::new(ctx), None, None, variant, Some(path));
         self.add(item);
     }
 
@@ -133,7 +133,7 @@ impl Completions {
         variant: hir::EnumVariant,
         local_name: Option<String>,
     ) {
-        let item = render_enum_variant(RenderContext::new(ctx), local_name, variant, None);
+        let item = render_enum_variant(RenderContext::new(ctx), None, local_name, variant, None);
         self.add(item);
     }
 }
diff --git a/crates/completion/src/completions/unqualified_path.rs b/crates/completion/src/completions/unqualified_path.rs
index 4f8ec1e67..86c143b63 100644
--- a/crates/completion/src/completions/unqualified_path.rs
+++ b/crates/completion/src/completions/unqualified_path.rs
@@ -1,14 +1,14 @@
 //! Completion of names from the current scope, e.g. locals and imported items.
 
-use assists::utils::{insert_use, mod_path_to_ast, ImportScope};
+use assists::utils::ImportScope;
 use either::Either;
 use hir::{Adt, ModuleDef, ScopeDef, Type};
 use ide_db::imports_locator;
-use syntax::{algo, AstNode};
+use syntax::AstNode;
 use test_utils::mark;
 
 use crate::{
-    render::{render_resolution, RenderContext},
+    render::{render_resolution_with_import, RenderContext},
     CompletionContext, Completions,
 };
 
@@ -95,35 +95,13 @@ fn fuzzy_completion(acc: &mut Completions, ctx: &CompletionContext) -> Option<()
                 )),
             })
             .filter(|(mod_path, _)| mod_path.len() > 1)
-            .filter_map(|(mod_path, definition)| {
-                let use_to_insert = mod_path_to_ast(&mod_path);
-                let mut mod_path_without_last_segment = mod_path;
-                let name_after_import = mod_path_without_last_segment.segments.pop()?.to_string();
-
-                let resolution_with_missing_import =
-                    render_resolution(RenderContext::new(ctx), name_after_import, &definition)?;
-                let lookup_string = resolution_with_missing_import.lookup().to_owned();
-
-                let mut text_edits =
-                    resolution_with_missing_import.text_edit().to_owned().into_builder();
-                let rewriter = insert_use(&import_scope, use_to_insert, ctx.config.merge);
-                let old_ast = rewriter.rewrite_root()?;
-                algo::diff(&old_ast, &rewriter.rewrite(&old_ast)).into_text_edit(&mut text_edits);
-
-                let qualifier_string = mod_path_without_last_segment.to_string();
-                let qualified_label = if qualifier_string.is_empty() {
-                    resolution_with_missing_import.label().to_owned()
-                } else {
-                    format!("{}::{}", qualifier_string, resolution_with_missing_import.label())
-                };
-
-                Some(
-                    resolution_with_missing_import
-                        .into_builder()
-                        .text_edit(text_edits.finish())
-                        .label(qualified_label)
-                        .lookup_by(lookup_string)
-                        .build(),
+            .filter_map(|(import_path, definition)| {
+                render_resolution_with_import(
+                    RenderContext::new(ctx),
+                    import_path.clone(),
+                    import_scope.clone(),
+                    ctx.config.merge,
+                    &definition,
                 )
             })
             .take(20);
diff --git a/crates/completion/src/item.rs b/crates/completion/src/item.rs
index 24b9d036a..b13c3f376 100644
--- a/crates/completion/src/item.rs
+++ b/crates/completion/src/item.rs
@@ -2,8 +2,9 @@
 
 use std::fmt;
 
-use hir::{Documentation, Mutability};
-use syntax::TextRange;
+use assists::utils::{insert_use, mod_path_to_ast, ImportScope, MergeBehaviour};
+use hir::{Documentation, ModPath, Mutability};
+use syntax::{algo, TextRange};
 use text_edit::TextEdit;
 
 use crate::config::SnippetCap;
@@ -200,25 +201,7 @@ impl CompletionItem {
             trigger_call_info: None,
             score: None,
             ref_match: None,
-        }
-    }
-
-    pub(crate) fn into_builder(self) -> Builder {
-        Builder {
-            source_range: self.source_range,
-            completion_kind: self.completion_kind,
-            label: self.label,
-            insert_text: None,
-            insert_text_format: self.insert_text_format,
-            detail: self.detail,
-            documentation: self.documentation,
-            lookup: self.lookup,
-            kind: self.kind,
-            text_edit: Some(self.text_edit),
-            deprecated: Some(self.deprecated),
-            trigger_call_info: Some(self.trigger_call_info),
-            score: self.score,
-            ref_match: self.ref_match,
+            import_data: None,
         }
     }
 
@@ -278,6 +261,7 @@ impl CompletionItem {
 pub(crate) struct Builder {
     source_range: TextRange,
     completion_kind: CompletionKind,
+    import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
     label: String,
     insert_text: Option<String>,
     insert_text_format: InsertTextFormat,
@@ -294,23 +278,50 @@ pub(crate) struct Builder {
 
 impl Builder {
     pub(crate) fn build(self) -> CompletionItem {
-        let label = self.label;
-        let text_edit = match self.text_edit {
+        let mut label = self.label;
+        let mut lookup = self.lookup;
+        let mut insert_text = self.insert_text;
+        let mut text_edits = TextEdit::builder();
+
+        if let Some((import_path, import_scope, merge_behaviour)) = self.import_data {
+            let import = mod_path_to_ast(&import_path);
+            let mut import_path_without_last_segment = import_path;
+            let _ = import_path_without_last_segment.segments.pop();
+
+            if !import_path_without_last_segment.segments.is_empty() {
+                if lookup.is_none() {
+                    lookup = Some(label.clone());
+                }
+                if insert_text.is_none() {
+                    insert_text = Some(label.clone());
+                }
+                label = format!("{}::{}", import_path_without_last_segment, label);
+            }
+
+            let rewriter = insert_use(&import_scope, import, merge_behaviour);
+            if let Some(old_ast) = rewriter.rewrite_root() {
+                algo::diff(&old_ast, &rewriter.rewrite(&old_ast)).into_text_edit(&mut text_edits);
+            }
+        }
+
+        let original_edit = match self.text_edit {
             Some(it) => it,
-            None => TextEdit::replace(
-                self.source_range,
-                self.insert_text.unwrap_or_else(|| label.clone()),
-            ),
+            None => {
+                TextEdit::replace(self.source_range, insert_text.unwrap_or_else(|| label.clone()))
+            }
         };
 
+        let mut resulting_edit = text_edits.finish();
+        resulting_edit.union(original_edit).expect("Failed to unite text edits");
+
         CompletionItem {
             source_range: self.source_range,
             label,
             insert_text_format: self.insert_text_format,
-            text_edit,
+            text_edit: resulting_edit,
             detail: self.detail,
             documentation: self.documentation,
-            lookup: self.lookup,
+            lookup,
             kind: self.kind,
             completion_kind: self.completion_kind,
             deprecated: self.deprecated.unwrap_or(false),
@@ -379,6 +390,13 @@ impl Builder {
         self.trigger_call_info = Some(true);
         self
     }
+    pub(crate) fn import_data(
+        mut self,
+        import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
+    ) -> Builder {
+        self.import_data = import_data;
+        self
+    }
     pub(crate) fn set_ref_match(
         mut self,
         ref_match: Option<(Mutability, CompletionScore)>,
diff --git a/crates/completion/src/render.rs b/crates/completion/src/render.rs
index 5a4353846..e892d4de8 100644
--- a/crates/completion/src/render.rs
+++ b/crates/completion/src/render.rs
@@ -9,7 +9,8 @@ pub(crate) mod type_alias;
 
 mod builder_ext;
 
-use hir::{Documentation, HasAttrs, HirDisplay, Mutability, ScopeDef, Type};
+use assists::utils::{ImportScope, MergeBehaviour};
+use hir::{Documentation, HasAttrs, HirDisplay, ModPath, Mutability, ScopeDef, Type};
 use ide_db::RootDatabase;
 use syntax::TextRange;
 use test_utils::mark;
@@ -42,7 +43,22 @@ pub(crate) fn render_resolution<'a>(
     local_name: String,
     resolution: &ScopeDef,
 ) -> Option<CompletionItem> {
-    Render::new(ctx).render_resolution(local_name, resolution)
+    Render::new(ctx).render_resolution(local_name, None, resolution)
+}
+
+pub(crate) fn render_resolution_with_import<'a>(
+    ctx: RenderContext<'a>,
+    import: ModPath,
+    import_scope: ImportScope,
+    merge_behaviour: Option<MergeBehaviour>,
+    resolution: &ScopeDef,
+) -> Option<CompletionItem> {
+    let local_name = import.segments.last()?.to_string();
+    Render::new(ctx).render_resolution(
+        local_name,
+        Some((import, import_scope, merge_behaviour)),
+        resolution,
+    )
 }
 
 /// Interface for data and methods required for items rendering.
@@ -131,6 +147,7 @@ impl<'a> Render<'a> {
     fn render_resolution(
         self,
         local_name: String,
+        import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
         resolution: &ScopeDef,
     ) -> Option<CompletionItem> {
         use hir::ModuleDef::*;
@@ -142,15 +159,15 @@ impl<'a> Render<'a> {
 
         let kind = match resolution {
             ScopeDef::ModuleDef(Function(func)) => {
-                let item = render_fn(self.ctx, Some(local_name), *func);
+                let item = render_fn(self.ctx, import_data, Some(local_name), *func);
                 return Some(item);
             }
             ScopeDef::ModuleDef(EnumVariant(var)) => {
-                let item = render_enum_variant(self.ctx, Some(local_name), *var, None);
+                let item = render_enum_variant(self.ctx, import_data, Some(local_name), *var, None);
                 return Some(item);
             }
             ScopeDef::MacroDef(mac) => {
-                let item = render_macro(self.ctx, local_name, *mac);
+                let item = render_macro(self.ctx, import_data, local_name, *mac);
                 return item;
             }
 
@@ -175,6 +192,7 @@ impl<'a> Render<'a> {
                     local_name,
                 )
                 .kind(CompletionItemKind::UnresolvedReference)
+                .import_data(import_data)
                 .build();
                 return Some(item);
             }
@@ -227,7 +245,12 @@ impl<'a> Render<'a> {
             }
         }
 
-        let item = item.kind(kind).set_documentation(docs).set_ref_match(ref_match).build();
+        let item = item
+            .kind(kind)
+            .import_data(import_data)
+            .set_documentation(docs)
+            .set_ref_match(ref_match)
+            .build();
         Some(item)
     }
 
diff --git a/crates/completion/src/render/enum_variant.rs b/crates/completion/src/render/enum_variant.rs
index fd412ed0e..6070e9b1d 100644
--- a/crates/completion/src/render/enum_variant.rs
+++ b/crates/completion/src/render/enum_variant.rs
@@ -1,5 +1,6 @@
 //! Renderer for `enum` variants.
 
+use assists::utils::{ImportScope, MergeBehaviour};
 use hir::{HasAttrs, HirDisplay, ModPath, StructKind};
 use itertools::Itertools;
 use test_utils::mark;
@@ -11,11 +12,12 @@ use crate::{
 
 pub(crate) fn render_enum_variant<'a>(
     ctx: RenderContext<'a>,
+    import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
     local_name: Option<String>,
     variant: hir::EnumVariant,
     path: Option<ModPath>,
 ) -> CompletionItem {
-    EnumVariantRender::new(ctx, local_name, variant, path).render()
+    EnumVariantRender::new(ctx, local_name, variant, path).render(import_data)
 }
 
 #[derive(Debug)]
@@ -60,7 +62,10 @@ impl<'a> EnumVariantRender<'a> {
         }
     }
 
-    fn render(self) -> CompletionItem {
+    fn render(
+        self,
+        import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
+    ) -> CompletionItem {
         let mut builder = CompletionItem::new(
             CompletionKind::Reference,
             self.ctx.source_range(),
@@ -69,6 +74,7 @@ impl<'a> EnumVariantRender<'a> {
         .kind(CompletionItemKind::EnumVariant)
         .set_documentation(self.variant.docs(self.ctx.db()))
         .set_deprecated(self.ctx.is_deprecated(self.variant))
+        .import_data(import_data)
         .detail(self.detail());
 
         if self.variant_kind == StructKind::Tuple {
diff --git a/crates/completion/src/render/function.rs b/crates/completion/src/render/function.rs
index 4fa6eafd7..9dd5cd18c 100644
--- a/crates/completion/src/render/function.rs
+++ b/crates/completion/src/render/function.rs
@@ -1,6 +1,7 @@
 //! Renderer for function calls.
 
-use hir::{HasSource, Type};
+use assists::utils::{ImportScope, MergeBehaviour};
+use hir::{HasSource, ModPath, Type};
 use syntax::{ast::Fn, display::function_declaration};
 
 use crate::{
@@ -10,10 +11,11 @@ use crate::{
 
 pub(crate) fn render_fn<'a>(
     ctx: RenderContext<'a>,
+    import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
     local_name: Option<String>,
     fn_: hir::Function,
 ) -> CompletionItem {
-    FunctionRender::new(ctx, local_name, fn_).render()
+    FunctionRender::new(ctx, local_name, fn_).render(import_data)
 }
 
 #[derive(Debug)]
@@ -36,7 +38,10 @@ impl<'a> FunctionRender<'a> {
         FunctionRender { ctx, name, fn_, ast_node }
     }
 
-    fn render(self) -> CompletionItem {
+    fn render(
+        self,
+        import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
+    ) -> CompletionItem {
         let params = self.params();
         CompletionItem::new(CompletionKind::Reference, self.ctx.source_range(), self.name.clone())
             .kind(self.kind())
@@ -44,6 +49,7 @@ impl<'a> FunctionRender<'a> {
             .set_deprecated(self.ctx.is_deprecated(self.fn_))
             .detail(self.detail())
             .add_call_parens(self.ctx.completion, self.name, params)
+            .import_data(import_data)
             .build()
     }
 
diff --git a/crates/completion/src/render/macro_.rs b/crates/completion/src/render/macro_.rs
index 96be59cc3..fead59e41 100644
--- a/crates/completion/src/render/macro_.rs
+++ b/crates/completion/src/render/macro_.rs
@@ -1,6 +1,7 @@
 //! Renderer for macro invocations.
 
-use hir::{Documentation, HasSource};
+use assists::utils::{ImportScope, MergeBehaviour};
+use hir::{Documentation, HasSource, ModPath};
 use syntax::display::macro_label;
 use test_utils::mark;
 
@@ -11,10 +12,11 @@ use crate::{
 
 pub(crate) fn render_macro<'a>(
     ctx: RenderContext<'a>,
+    import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
     name: String,
     macro_: hir::MacroDef,
 ) -> Option<CompletionItem> {
-    MacroRender::new(ctx, name, macro_).render()
+    MacroRender::new(ctx, name, macro_).render(import_data)
 }
 
 #[derive(Debug)]
@@ -36,7 +38,10 @@ impl<'a> MacroRender<'a> {
         MacroRender { ctx, name, macro_, docs, bra, ket }
     }
 
-    fn render(&self) -> Option<CompletionItem> {
+    fn render(
+        &self,
+        import_data: Option<(ModPath, ImportScope, Option<MergeBehaviour>)>,
+    ) -> Option<CompletionItem> {
         // FIXME: Currently proc-macro do not have ast-node,
         // such that it does not have source
         if self.macro_.is_proc_macro() {
@@ -48,6 +53,7 @@ impl<'a> MacroRender<'a> {
                 .kind(CompletionItemKind::Macro)
                 .set_documentation(self.docs.clone())
                 .set_deprecated(self.ctx.is_deprecated(self.macro_))
+                .import_data(import_data)
                 .detail(self.detail());
 
         let needs_bang = self.needs_bang();