Auto merge of #81993 - flip1995:clippyup, r=Manishearth

[rust.git] / clippy_lints / src / format.rs

diff --git a/clippy_lints/src/format.rs b/clippy_lints/src/format.rs
index 3082153fa998e5245fa59fa07d16c8308eaa5e39..8e41e0e34daf75bc6f87242e19dc38756a30248a 100644 (file)
--- a/clippy_lints/src/format.rs
+++ b/clippy_lints/src/format.rs
@@ -1,15 +1,16 @@
 use crate::utils::paths;
 use crate::utils::{
-    is_expn_of, last_path_segment, match_def_path, match_function_call, match_type, snippet, span_lint_and_then,
-    walk_ptrs_ty,
+    is_expn_of, is_type_diagnostic_item, last_path_segment, match_def_path, match_function_call, snippet, snippet_opt,
+    span_lint_and_then,
 };
 use if_chain::if_chain;
-use rustc::lint::{LateContext, LateLintPass, LintContext};
+use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
-use rustc_hir::*;
+use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, MatchSource, PatKind};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
-use syntax::ast::LitKind;
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for the use of `format!("string literal with no
@@ -25,9 +26,13 @@
     ///
     /// **Examples:**
     /// ```rust
+    ///
+    /// // Bad
     /// # let foo = "foo";
-    /// format!("foo");
     /// format!("{}", foo);
+    ///
+    /// // Good
+    /// format!("foo");
     /// ```
     pub USELESS_FORMAT,
     complexity,
@@ -36,8 +41,8 @@
 
 declare_lint_pass!(UselessFormat => [USELESS_FORMAT]);
 
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UselessFormat {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+impl<'tcx> LateLintPass<'tcx> for UselessFormat {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         let span = match is_expn_of(expr.span, "format") {
             Some(s) if !s.from_expansion() => s,
             _ => return,
@@ -61,8 +66,8 @@ fn span_useless_format<T: LintContext>(cx: &T, span: Span, help: &str, mut sugg:
         sugg.push(';');
     }
 
-    span_lint_and_then(cx, USELESS_FORMAT, span, "useless use of `format!`", |db| {
-        db.span_suggestion(
+    span_lint_and_then(cx, USELESS_FORMAT, span, "useless use of `format!`", |diag| {
+        diag.span_suggestion(
             to_replace,
             help,
             sugg,
@@ -71,11 +76,7 @@ fn span_useless_format<T: LintContext>(cx: &T, span: Span, help: &str, mut sugg:
     });
 }
 
-fn on_argumentv1_new<'a, 'tcx>(
-    cx: &LateContext<'a, 'tcx>,
-    expr: &'tcx Expr<'_>,
-    arms: &'tcx [Arm<'_>],
-) -> Option<String> {
+fn on_argumentv1_new<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arms: &'tcx [Arm<'_>]) -> Option<String> {
     if_chain! {
         if let ExprKind::AddrOf(BorrowKind::Ref, _, ref format_args) = expr.kind;
         if let ExprKind::Array(ref elems) = arms[0].body.kind;
@@ -84,14 +85,14 @@ fn on_argumentv1_new<'a, 'tcx>(
         // matches `core::fmt::Display::fmt`
         if args.len() == 2;
         if let ExprKind::Path(ref qpath) = args[1].kind;
-        if let Some(did) = cx.tables.qpath_res(qpath, args[1].hir_id).opt_def_id();
+        if let Some(did) = cx.qpath_res(qpath, args[1].hir_id).opt_def_id();
         if match_def_path(cx, did, &paths::DISPLAY_FMT_METHOD);
         // check `(arg0,)` in match block
         if let PatKind::Tuple(ref pats, None) = arms[0].pat.kind;
         if pats.len() == 1;
         then {
-            let ty = walk_ptrs_ty(cx.tables.pat_ty(&pats[0]));
-            if ty.kind != rustc::ty::Str && !match_type(cx, ty, &paths::STRING) {
+            let ty = cx.typeck_results().pat_ty(&pats[0]).peel_refs();
+            if *ty.kind() != rustc_middle::ty::Str && !is_type_diagnostic_item(cx, ty, sym::string_type) {
                 return None;
             }
             if let ExprKind::Lit(ref lit) = format_args.kind {
@@ -100,7 +101,7 @@ fn on_argumentv1_new<'a, 'tcx>(
                 }
             } else {
                 let snip = snippet(cx, format_args.span, "<arg>");
-                if let ExprKind::MethodCall(ref path, _, _) = format_args.kind {
+                if let ExprKind::MethodCall(ref path, _, _, _) = format_args.kind {
                     if path.ident.name == sym!(to_string) {
                         return Some(format!("{}", snip));
                     }
@@ -114,7 +115,7 @@ fn on_argumentv1_new<'a, 'tcx>(
     None
 }
 
-fn on_new_v1<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
+fn on_new_v1<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
     if_chain! {
         if let Some(args) = match_function_call(cx, expr, &paths::FMT_ARGUMENTS_NEW_V1);
         if args.len() == 2;
@@ -132,7 +133,11 @@ fn on_new_v1<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> Opti
         then {
             // `format!("foo")` expansion contains `match () { () => [], }`
             if tup.is_empty() {
-                return Some(format!("{:?}.to_string()", s.as_str()));
+                if let Some(s_src) = snippet_opt(cx, lit.span) {
+                    // Simulate macro expansion, converting {{ and }} to { and }.
+                    let s_expand = s_src.replace("{{", "{").replace("}}", "}");
+                    return Some(format!("{}.to_string()", s_expand))
+                }
             } else if s.as_str().is_empty() {
                 return on_argumentv1_new(cx, &tup[0], arms);
             }
@@ -141,7 +146,7 @@ fn on_new_v1<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> Opti
     None
 }
 
-fn on_new_v1_fmt<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
+fn on_new_v1_fmt<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
     if_chain! {
         if let Some(args) = match_function_call(cx, expr, &paths::FMT_ARGUMENTS_NEW_V1_FORMATTED);
         if args.len() == 3;
@@ -182,15 +187,15 @@ fn check_unformatted(expr: &Expr<'_>) -> bool {
         if exprs.len() == 1;
         // struct `core::fmt::rt::v1::Argument`
         if let ExprKind::Struct(_, ref fields, _) = exprs[0].kind;
-        if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym!(format));
+        if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym::format);
         // struct `core::fmt::rt::v1::FormatSpec`
         if let ExprKind::Struct(_, ref fields, _) = format_field.expr.kind;
-        if let Some(precision_field) = fields.iter().find(|f| f.ident.name == sym!(precision));
+        if let Some(precision_field) = fields.iter().find(|f| f.ident.name == sym::precision);
         if let ExprKind::Path(ref precision_path) = precision_field.expr.kind;
-        if last_path_segment(precision_path).ident.name == sym!(Implied);
-        if let Some(width_field) = fields.iter().find(|f| f.ident.name == sym!(width));
+        if last_path_segment(precision_path).ident.name == sym::Implied;
+        if let Some(width_field) = fields.iter().find(|f| f.ident.name == sym::width);
         if let ExprKind::Path(ref width_qpath) = width_field.expr.kind;
-        if last_path_segment(width_qpath).ident.name == sym!(Implied);
+        if last_path_segment(width_qpath).ident.name == sym::Implied;
         then {
             return true;
         }