Nice string formatting

Cargo.lock

@@ -966,6 +966,7 @@ dependencies = [
  "ra_syntax",
  "ra_tt",
  "rustc-hash",
+ "stdx",
  "test_utils",
 ]
 
@@ -1002,6 +1003,7 @@ dependencies = [
  "ra_prof",
  "ra_syntax",
  "rustc-hash",
+ "stdx",
  "test_utils",
 ]
 
@@ -1116,6 +1118,7 @@ dependencies = [
  "rustc_lexer",
  "serde",
  "smol_str",
+ "stdx",
  "test_utils",
  "walkdir",
 ]
@@ -1307,6 +1310,7 @@ dependencies = [
  "rustc-hash",
  "serde",
  "serde_json",
+ "stdx",
  "tempfile",
  "test_utils",
  "threadpool",

crates/ra_hir_def/Cargo.toml

@@ -15,6 +15,8 @@ either = "1.5.3"
 anymap = "0.12.1"
 drop_bomb = "0.1.4"
 
+stdx = { path = "../stdx" }
+
 ra_arena = { path = "../ra_arena" }
 ra_db = { path = "../ra_db" }
 ra_syntax = { path = "../ra_syntax" }

crates/ra_hir_def/src/nameres.rs

@@ -63,6 +63,7 @@ use ra_db::{CrateId, Edition, FileId};
 use ra_prof::profile;
 use ra_syntax::ast;
 use rustc_hash::FxHashMap;
+use stdx::format_to;
 
 use crate::{
     db::DefDatabase,
@@ -246,7 +247,7 @@ impl CrateDefMap {
             entries.sort_by_key(|(name, _)| name.clone());
 
             for (name, def) in entries {
-                *buf += &format!("{}:", name);
+                format_to!(buf, "{}:", name);
 
                 if def.types.is_some() {
                     *buf += " t";
@@ -265,7 +266,7 @@ impl CrateDefMap {
             }
 
             for (name, child) in map.modules[module].children.iter() {
-                let path = path.to_string() + &format!("::{}", name);
+                let path = &format!("{}::{}", path, name);
                 go(buf, map, &path, *child);
             }
         }

crates/ra_hir_ty/Cargo.toml

@@ -13,6 +13,8 @@ ena = "0.13.1"
 log = "0.4.8"
 rustc-hash = "1.1.0"
 
+stdx = { path = "../stdx" }
+
 hir_def = { path = "../ra_hir_def", package = "ra_hir_def" }
 hir_expand = { path = "../ra_hir_expand", package = "ra_hir_expand" }
 ra_arena = { path = "../ra_arena" }

crates/ra_hir_ty/src/test_db.rs

@@ -10,6 +10,7 @@ use hir_expand::{db::AstDatabase, diagnostics::DiagnosticSink};
 use ra_db::{
     salsa, CrateId, FileId, FileLoader, FileLoaderDelegate, RelativePath, SourceDatabase, Upcast,
 };
+use stdx::format_to;
 
 use crate::{db::HirDatabase, expr::ExprValidator};
 
@@ -131,7 +132,7 @@ impl TestDB {
             for f in fns {
                 let infer = self.infer(f.into());
                 let mut sink = DiagnosticSink::new(|d| {
-                    buf += &format!("{:?}: {}\n", d.syntax_node(self).text(), d.message());
+                    format_to!(buf, "{:?}: {}\n", d.syntax_node(self).text(), d.message());
                 });
                 infer.add_diagnostics(self, f, &mut sink);
                 let mut validator = ExprValidator::new(f, infer, &mut sink);

crates/ra_syntax/Cargo.toml

@@ -18,6 +18,8 @@ rustc-hash = "1.1.0"
 arrayvec = "0.5.1"
 once_cell = "1.3.1"
 
+stdx = { path = "../stdx" }
+
 ra_text_edit = { path = "../ra_text_edit" }
 ra_parser = { path = "../ra_parser" }
 

crates/ra_syntax/src/ast/make.rs

@@ -1,6 +1,7 @@
 //! This module contains free-standing functions for creating AST fragments out
 //! of smaller pieces.
 use itertools::Itertools;
+use stdx::format_to;
 
 use crate::{ast, AstNode, SourceFile, SyntaxKind, SyntaxNode, SyntaxToken};
 
@@ -34,14 +35,14 @@ pub fn use_tree(
     let mut buf = "use ".to_string();
     buf += &path.syntax().to_string();
     if let Some(use_tree_list) = use_tree_list {
-        buf += &format!("::{}", use_tree_list);
+        format_to!(buf, "::{}", use_tree_list);
     }
     if add_star {
         buf += "::*";
     }
 
     if let Some(alias) = alias {
-        buf += &format!(" {}", alias);
+        format_to!(buf, " {}", alias);
     }
     ast_from_text(&buf)
 }
@@ -70,15 +71,15 @@ pub fn block_expr(
     stmts: impl IntoIterator<Item = ast::Stmt>,
     tail_expr: Option<ast::Expr>,
 ) -> ast::BlockExpr {
-    let mut text = "{\n".to_string();
+    let mut buf = "{\n".to_string();
     for stmt in stmts.into_iter() {
-        text += &format!("    {}\n", stmt);
+        format_to!(buf, "    {}\n", stmt);
     }
     if let Some(tail_expr) = tail_expr {
-        text += &format!("    {}\n", tail_expr)
+        format_to!(buf, "    {}\n", tail_expr)
     }
-    text += "}";
+    buf += "}";
-    ast_from_text(&format!("fn f() {}", text))
+    ast_from_text(&format!("fn f() {}", buf))
 }
 
 pub fn block_from_expr(e: ast::Expr) -> ast::Block {

crates/ra_syntax/src/lib.rs

@@ -32,9 +32,10 @@ pub mod ast;
 #[doc(hidden)]
 pub mod fuzz;
 
-use std::{fmt::Write, marker::PhantomData, sync::Arc};
+use std::{marker::PhantomData, sync::Arc};
 
 use ra_text_edit::AtomTextEdit;
+use stdx::format_to;
 
 use crate::syntax_node::GreenNode;
 
@@ -115,7 +116,7 @@ impl Parse<SourceFile> {
     pub fn debug_dump(&self) -> String {
         let mut buf = format!("{:#?}", self.tree().syntax());
         for err in self.errors.iter() {
-            writeln!(buf, "error {:?}: {}", err.range(), err).unwrap();
+            format_to!(buf, "error {:?}: {}\n", err.range(), err);
         }
         buf
     }
@@ -296,7 +297,7 @@ fn api_walkthrough() {
                     NodeOrToken::Node(it) => it.text().to_string(),
                     NodeOrToken::Token(it) => it.text().to_string(),
                 };
-                buf += &format!("{:indent$}{:?} {:?}\n", " ", text, node.kind(), indent = indent);
+                format_to!(buf, "{:indent$}{:?} {:?}\n", " ", text, node.kind(), indent = indent);
                 indent += 2;
             }
             WalkEvent::Leave(_) => indent -= 2,

crates/rust-analyzer/Cargo.toml

@@ -30,6 +30,8 @@ serde = { version = "1.0.104", features = ["derive"] }
 serde_json = "1.0.48"
 threadpool = "1.7.1"
 
+stdx = { path = "../stdx" }
+
 lsp-server = "0.3.1"
 ra_cargo_watch = { path = "../ra_cargo_watch" }
 ra_ide = { path = "../ra_ide" }

crates/rust-analyzer/src/world.rs

@@ -19,6 +19,7 @@ use ra_ide::{
 use ra_project_model::{get_rustc_cfg_options, ProcMacroClient, ProjectWorkspace};
 use ra_vfs::{LineEndings, RootEntry, Vfs, VfsChange, VfsFile, VfsRoot, VfsTask, Watch};
 use relative_path::RelativePathBuf;
+use stdx::format_to;
 
 use crate::{
     diagnostics::{CheckFixes, DiagnosticCollection},
@@ -319,23 +320,23 @@ impl WorldSnapshot {
     }
 
     pub fn status(&self) -> String {
-        let mut res = String::new();
+        let mut buf = String::new();
         if self.workspaces.is_empty() {
-            res.push_str("no workspaces\n")
+            buf.push_str("no workspaces\n")
         } else {
-            res.push_str("workspaces:\n");
+            buf.push_str("workspaces:\n");
             for w in self.workspaces.iter() {
-                res += &format!("{} packages loaded\n", w.n_packages());
+                format_to!(buf, "{} packages loaded\n", w.n_packages());
             }
         }
-        res.push_str("\nanalysis:\n");
+        buf.push_str("\nanalysis:\n");
-        res.push_str(
+        buf.push_str(
             &self
                 .analysis
                 .status()
                 .unwrap_or_else(|_| "Analysis retrieval was cancelled".to_owned()),
         );
-        res
+        buf
     }
 
     pub fn workspace_root_for(&self, file_id: FileId) -> Option<&Path> {

crates/stdx/src/lib.rs

@@ -21,7 +21,7 @@ where
     I: Iterator,
     I::Item: fmt::Display,
 {
-    fn sep_by<'a>(self, sep: &'a std::primitive::str) -> SepByBuilder<'a, Self> {
+    fn sep_by<'a>(self, sep: &'a str) -> SepByBuilder<'a, Self> {
         SepByBuilder::new(sep, self)
     }
 }