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diff --git a/crates/ra_ide/src/completion/completion_item.rs b/crates/ra_ide/src/completion/completion_item.rs
new file mode 100644
index 000000000..93f336370
--- /dev/null
+++ b/crates/ra_ide/src/completion/completion_item.rs
@@ -0,0 +1,322 @@
+//! FIXME: write short doc here
+
+use std::fmt;
+
+use hir::Documentation;
+use ra_syntax::TextRange;
+use ra_text_edit::TextEdit;
+
+/// `CompletionItem` describes a single completion variant in the editor pop-up.
+/// It is basically a POD with various properties. To construct a
+/// `CompletionItem`, use `new` method and the `Builder` struct.
+pub struct CompletionItem {
+    /// Used only internally in tests, to check only specific kind of
+    /// completion (postfix, keyword, reference, etc).
+    #[allow(unused)]
+    completion_kind: CompletionKind,
+    /// Label in the completion pop up which identifies completion.
+    label: String,
+    /// Range of identifier that is being completed.
+    ///
+    /// It should be used primarily for UI, but we also use this to convert
+    /// genetic TextEdit into LSP's completion edit (see conv.rs).
+    ///
+    /// `source_range` must contain the completion offset. `insert_text` should
+    /// start with what `source_range` points to, or VSCode will filter out the
+    /// completion silently.
+    source_range: TextRange,
+    /// What happens when user selects this item.
+    ///
+    /// Typically, replaces `source_range` with new identifier.
+    text_edit: TextEdit,
+    insert_text_format: InsertTextFormat,
+
+    /// What item (struct, function, etc) are we completing.
+    kind: Option<CompletionItemKind>,
+
+    /// Lookup is used to check if completion item indeed can complete current
+    /// ident.
+    ///
+    /// That is, in `foo.bar<|>` lookup of `abracadabra` will be accepted (it
+    /// contains `bar` sub sequence), and `quux` will rejected.
+    lookup: Option<String>,
+
+    /// Additional info to show in the UI pop up.
+    detail: Option<String>,
+    documentation: Option<Documentation>,
+
+    /// Whether this item is marked as deprecated
+    deprecated: bool,
+}
+
+// We use custom debug for CompletionItem to make `insta`'s diffs more readable.
+impl fmt::Debug for CompletionItem {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut s = f.debug_struct("CompletionItem");
+        s.field("label", &self.label()).field("source_range", &self.source_range());
+        if self.text_edit().as_atoms().len() == 1 {
+            let atom = &self.text_edit().as_atoms()[0];
+            s.field("delete", &atom.delete);
+            s.field("insert", &atom.insert);
+        } else {
+            s.field("text_edit", &self.text_edit);
+        }
+        if let Some(kind) = self.kind().as_ref() {
+            s.field("kind", kind);
+        }
+        if self.lookup() != self.label() {
+            s.field("lookup", &self.lookup());
+        }
+        if let Some(detail) = self.detail() {
+            s.field("detail", &detail);
+        }
+        if let Some(documentation) = self.documentation() {
+            s.field("documentation", &documentation);
+        }
+        if self.deprecated {
+            s.field("deprecated", &true);
+        }
+        s.finish()
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CompletionItemKind {
+    Snippet,
+    Keyword,
+    Module,
+    Function,
+    BuiltinType,
+    Struct,
+    Enum,
+    EnumVariant,
+    Binding,
+    Field,
+    Static,
+    Const,
+    Trait,
+    TypeAlias,
+    Method,
+    TypeParam,
+    Macro,
+}
+
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub(crate) enum CompletionKind {
+    /// Parser-based keyword completion.
+    Keyword,
+    /// Your usual "complete all valid identifiers".
+    Reference,
+    /// "Secret sauce" completions.
+    Magic,
+    Snippet,
+    Postfix,
+    BuiltinType,
+}
+
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub enum InsertTextFormat {
+    PlainText,
+    Snippet,
+}
+
+impl CompletionItem {
+    pub(crate) fn new(
+        completion_kind: CompletionKind,
+        source_range: TextRange,
+        label: impl Into<String>,
+    ) -> Builder {
+        let label = label.into();
+        Builder {
+            source_range,
+            completion_kind,
+            label,
+            insert_text: None,
+            insert_text_format: InsertTextFormat::PlainText,
+            detail: None,
+            documentation: None,
+            lookup: None,
+            kind: None,
+            text_edit: None,
+            deprecated: None,
+        }
+    }
+    /// What user sees in pop-up in the UI.
+    pub fn label(&self) -> &str {
+        &self.label
+    }
+    pub fn source_range(&self) -> TextRange {
+        self.source_range
+    }
+
+    pub fn insert_text_format(&self) -> InsertTextFormat {
+        self.insert_text_format
+    }
+
+    pub fn text_edit(&self) -> &TextEdit {
+        &self.text_edit
+    }
+
+    /// Short one-line additional information, like a type
+    pub fn detail(&self) -> Option<&str> {
+        self.detail.as_ref().map(|it| it.as_str())
+    }
+    /// A doc-comment
+    pub fn documentation(&self) -> Option<Documentation> {
+        self.documentation.clone()
+    }
+    /// What string is used for filtering.
+    pub fn lookup(&self) -> &str {
+        self.lookup.as_ref().map(|it| it.as_str()).unwrap_or_else(|| self.label())
+    }
+
+    pub fn kind(&self) -> Option<CompletionItemKind> {
+        self.kind
+    }
+
+    pub fn deprecated(&self) -> bool {
+        self.deprecated
+    }
+}
+
+/// A helper to make `CompletionItem`s.
+#[must_use]
+pub(crate) struct Builder {
+    source_range: TextRange,
+    completion_kind: CompletionKind,
+    label: String,
+    insert_text: Option<String>,
+    insert_text_format: InsertTextFormat,
+    detail: Option<String>,
+    documentation: Option<Documentation>,
+    lookup: Option<String>,
+    kind: Option<CompletionItemKind>,
+    text_edit: Option<TextEdit>,
+    deprecated: Option<bool>,
+}
+
+impl Builder {
+    pub(crate) fn add_to(self, acc: &mut Completions) {
+        acc.add(self.build())
+    }
+
+    pub(crate) fn build(self) -> CompletionItem {
+        let label = self.label;
+        let text_edit = match self.text_edit {
+            Some(it) => it,
+            None => TextEdit::replace(
+                self.source_range,
+                self.insert_text.unwrap_or_else(|| label.clone()),
+            ),
+        };
+
+        CompletionItem {
+            source_range: self.source_range,
+            label,
+            insert_text_format: self.insert_text_format,
+            text_edit,
+            detail: self.detail,
+            documentation: self.documentation,
+            lookup: self.lookup,
+            kind: self.kind,
+            completion_kind: self.completion_kind,
+            deprecated: self.deprecated.unwrap_or(false),
+        }
+    }
+    pub(crate) fn lookup_by(mut self, lookup: impl Into<String>) -> Builder {
+        self.lookup = Some(lookup.into());
+        self
+    }
+    pub(crate) fn label(mut self, label: impl Into<String>) -> Builder {
+        self.label = label.into();
+        self
+    }
+    pub(crate) fn insert_text(mut self, insert_text: impl Into<String>) -> Builder {
+        self.insert_text = Some(insert_text.into());
+        self
+    }
+    pub(crate) fn insert_snippet(mut self, snippet: impl Into<String>) -> Builder {
+        self.insert_text_format = InsertTextFormat::Snippet;
+        self.insert_text(snippet)
+    }
+    pub(crate) fn kind(mut self, kind: CompletionItemKind) -> Builder {
+        self.kind = Some(kind);
+        self
+    }
+    pub(crate) fn text_edit(mut self, edit: TextEdit) -> Builder {
+        self.text_edit = Some(edit);
+        self
+    }
+    pub(crate) fn snippet_edit(mut self, edit: TextEdit) -> Builder {
+        self.insert_text_format = InsertTextFormat::Snippet;
+        self.text_edit(edit)
+    }
+    #[allow(unused)]
+    pub(crate) fn detail(self, detail: impl Into<String>) -> Builder {
+        self.set_detail(Some(detail))
+    }
+    pub(crate) fn set_detail(mut self, detail: Option<impl Into<String>>) -> Builder {
+        self.detail = detail.map(Into::into);
+        self
+    }
+    #[allow(unused)]
+    pub(crate) fn documentation(self, docs: Documentation) -> Builder {
+        self.set_documentation(Some(docs))
+    }
+    pub(crate) fn set_documentation(mut self, docs: Option<Documentation>) -> Builder {
+        self.documentation = docs.map(Into::into);
+        self
+    }
+    pub(crate) fn set_deprecated(mut self, deprecated: bool) -> Builder {
+        self.deprecated = Some(deprecated);
+        self
+    }
+}
+
+impl<'a> Into<CompletionItem> for Builder {
+    fn into(self) -> CompletionItem {
+        self.build()
+    }
+}
+
+/// Represents an in-progress set of completions being built.
+#[derive(Debug, Default)]
+pub(crate) struct Completions {
+    buf: Vec<CompletionItem>,
+}
+
+impl Completions {
+    pub(crate) fn add(&mut self, item: impl Into<CompletionItem>) {
+        self.buf.push(item.into())
+    }
+    pub(crate) fn add_all<I>(&mut self, items: I)
+    where
+        I: IntoIterator,
+        I::Item: Into<CompletionItem>,
+    {
+        items.into_iter().for_each(|item| self.add(item.into()))
+    }
+}
+
+impl Into<Vec<CompletionItem>> for Completions {
+    fn into(self) -> Vec<CompletionItem> {
+        self.buf
+    }
+}
+
+#[cfg(test)]
+pub(crate) fn do_completion(code: &str, kind: CompletionKind) -> Vec<CompletionItem> {
+    use crate::completion::completions;
+    use crate::mock_analysis::{analysis_and_position, single_file_with_position};
+    let (analysis, position) = if code.contains("//-") {
+        analysis_and_position(code)
+    } else {
+        single_file_with_position(code)
+    };
+    let completions = completions(&analysis.db, position).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();
+    kind_completions.sort_by_key(|c| c.label.clone());
+    kind_completions
+}