5 files changed, 45 insertions, 53 deletions

diff --git a/crates/ra_ide/src/completion/presentation.rs b/crates/ra_ide/src/completion/presentation.rs
index 253848602..60f1b83f3 100644
--- a/crates/ra_ide/src/completion/presentation.rs
+++ b/crates/ra_ide/src/completion/presentation.rs
@@ -1,15 +1,14 @@
 //! This modules takes care of rendering various definitions as completion items.
 
 use hir::{Docs, HasAttrs, HasSource, HirDisplay, ScopeDef, StructKind, Type};
-use join_to_string::join;
 use ra_syntax::ast::NameOwner;
+use stdx::SepBy;
 use test_utils::tested_by;
 
-use crate::completion::{
-    CompletionContext, CompletionItem, CompletionItemKind, CompletionKind, Completions,
-};
-
 use crate::{
+    completion::{
+        CompletionContext, CompletionItem, CompletionItemKind, CompletionKind, Completions,
+    },
     display::{const_label, macro_label, type_label, FunctionSignature},
     RootDatabase,
 };
@@ -221,13 +220,13 @@ impl Completions {
                 builder = builder.trigger_call_info();
                 let snippet = if ctx.options.add_call_argument_snippets {
                     let to_skip = if has_self_param { 1 } else { 0 };
-                    let function_params_snippet = join(
-                        function_signature.parameter_names.iter().skip(to_skip).enumerate().map(
-                            |(index, param_name)| format!("${{{}:{}}}", index + 1, param_name),
-                        ),
-                    )
-                    .separator(", ")
-                    .to_string();
+                    let function_params_snippet = function_signature
+                        .parameter_names
+                        .iter()
+                        .skip(to_skip)
+                        .enumerate()
+                        .map(|(index, param_name)| format!("${{{}:{}}}", index + 1, param_name))
+                        .sep_by(", ");
                     format!("{}({})$0", name, function_params_snippet)
                 } else {
                     format!("{}($0)", name)
@@ -281,18 +280,16 @@ impl Completions {
             .into_iter()
             .map(|field| (field.name(ctx.db), field.signature_ty(ctx.db)));
         let detail = match variant.kind(ctx.db) {
-            StructKind::Tuple | StructKind::Unit => {
-                join(detail_types.map(|(_, t)| t.display(ctx.db).to_string()))
-                    .separator(", ")
-                    .surround_with("(", ")")
-                    .to_string()
-            }
-            StructKind::Record => {
-                join(detail_types.map(|(n, t)| format!("{}: {}", n, t.display(ctx.db).to_string())))
-                    .separator(", ")
-                    .surround_with("{ ", " }")
-                    .to_string()
-            }
+            StructKind::Tuple | StructKind::Unit => detail_types
+                .map(|(_, t)| t.display(ctx.db).to_string())
+                .sep_by(", ")
+                .surround_with("(", ")")
+                .to_string(),
+            StructKind::Record => detail_types
+                .map(|(n, t)| format!("{}: {}", n, t.display(ctx.db).to_string()))
+                .sep_by(", ")
+                .surround_with("{ ", " }")
+                .to_string(),
         };
         CompletionItem::new(CompletionKind::Reference, ctx.source_range(), name.to_string())
             .kind(CompletionItemKind::EnumVariant)
diff --git a/crates/ra_ide/src/diagnostics.rs b/crates/ra_ide/src/diagnostics.rs
index a10e642db..c1d7ddaf2 100644
--- a/crates/ra_ide/src/diagnostics.rs
+++ b/crates/ra_ide/src/diagnostics.rs
@@ -200,8 +200,8 @@ fn check_struct_shorthand_initialization(
 #[cfg(test)]
 mod tests {
     use insta::assert_debug_snapshot;
-    use join_to_string::join;
     use ra_syntax::SourceFile;
+    use stdx::SepBy;
     use test_utils::assert_eq_text;
 
     use crate::mock_analysis::{analysis_and_position, single_file};
@@ -254,16 +254,12 @@ mod tests {
             .map(|it| it.len() - it.trim_start().len())
             .next()
             .expect("empty fixture");
-        let after = join(after.lines().filter_map(|line| {
-            if line.len() > margin {
-                Some(&line[margin..])
-            } else {
-                None
-            }
-        }))
-        .separator("\n")
-        .suffix("\n")
-        .to_string();
+        let after = after
+            .lines()
+            .filter_map(|line| if line.len() > margin { Some(&line[margin..]) } else { None })
+            .sep_by("\n")
+            .suffix("\n")
+            .to_string();
 
         assert_eq_text!(&after, &actual);
         assert!(
diff --git a/crates/ra_ide/src/display.rs b/crates/ra_ide/src/display.rs
index c395057a7..722092de9 100644
--- a/crates/ra_ide/src/display.rs
+++ b/crates/ra_ide/src/display.rs
@@ -6,12 +6,13 @@ mod navigation_target;
 mod structure;
 mod short_label;
 
-use std::fmt::{Display, Write};
+use std::fmt::Display;
 
 use ra_syntax::{
     ast::{self, AstNode, AttrsOwner, NameOwner, TypeParamsOwner},
     SyntaxKind::{ATTR, COMMENT},
 };
+use stdx::format_to;
 
 pub use function_signature::FunctionSignature;
 pub use navigation_target::NavigationTarget;
@@ -78,18 +79,18 @@ pub(crate) fn rust_code_markup_with_doc(
     doc: Option<&str>,
     mod_path: Option<&str>,
 ) -> String {
-    let mut markup = "```rust\n".to_owned();
+    let mut buf = "```rust\n".to_owned();
 
     if let Some(mod_path) = mod_path {
         if !mod_path.is_empty() {
-            write!(markup, "{}\n", mod_path).unwrap();
+            format_to!(buf, "{}\n", mod_path);
         }
     }
-    write!(markup, "{}\n```", code).unwrap();
+    format_to!(buf, "{}\n```", code);
 
     if let Some(doc) = doc {
-        write!(markup, "\n\n{}", doc).unwrap();
+        format_to!(buf, "\n\n{}", doc);
     }
 
-    markup
+    buf
 }
diff --git a/crates/ra_ide/src/display/function_signature.rs b/crates/ra_ide/src/display/function_signature.rs
index ec1bbd5a0..b967a6816 100644
--- a/crates/ra_ide/src/display/function_signature.rs
+++ b/crates/ra_ide/src/display/function_signature.rs
@@ -1,12 +1,14 @@
 //! FIXME: write short doc here
 
-use std::fmt::{self, Display};
+use std::{
+    convert::From,
+    fmt::{self, Display},
+};
 
 use hir::{Docs, Documentation, HasSource, HirDisplay};
-use join_to_string::join;
 use ra_ide_db::RootDatabase;
 use ra_syntax::ast::{self, AstNode, NameOwner, VisibilityOwner};
-use std::convert::From;
+use stdx::SepBy;
 
 use crate::display::{generic_parameters, where_predicates};
 
@@ -227,21 +229,17 @@ impl Display for FunctionSignature {
         }
 
         if !self.generic_parameters.is_empty() {
-            join(self.generic_parameters.iter())
-                .separator(", ")
-                .surround_with("<", ">")
-                .to_fmt(f)?;
+            write!(f, "{}", self.generic_parameters.iter().sep_by(", ").surround_with("<", ">"))?;
         }
 
-        join(self.parameters.iter()).separator(", ").surround_with("(", ")").to_fmt(f)?;
+        write!(f, "{}", self.parameters.iter().sep_by(", ").surround_with("(", ")"))?;
 
         if let Some(t) = &self.ret_type {
             write!(f, " -> {}", t)?;
         }
 
         if !self.where_predicates.is_empty() {
-            write!(f, "\nwhere ")?;
-            join(self.where_predicates.iter()).separator(",\n      ").to_fmt(f)?;
+            write!(f, "\nwhere {}", self.where_predicates.iter().sep_by(",\n      "))?;
         }
 
         Ok(())
diff --git a/crates/ra_ide/src/display/short_label.rs b/crates/ra_ide/src/display/short_label.rs
index 9ffc9b980..4b081bf6c 100644
--- a/crates/ra_ide/src/display/short_label.rs
+++ b/crates/ra_ide/src/display/short_label.rs
@@ -1,7 +1,7 @@
 //! FIXME: write short doc here
 
-use format_buf::format;
 use ra_syntax::ast::{self, AstNode, NameOwner, TypeAscriptionOwner, VisibilityOwner};
+use stdx::format_to;
 
 pub(crate) trait ShortLabel {
     fn short_label(&self) -> Option<String>;
@@ -80,7 +80,7 @@ where
     let mut buf = short_label_from_node(node, prefix)?;
 
     if let Some(type_ref) = node.ascribed_type() {
-        format!(buf, ": {}", type_ref.syntax());
+        format_to!(buf, ": {}", type_ref.syntax());
     }
 
     Some(buf)