move get_hint_if_single_char_arg to methods/utils.rs

clippy_lints/src/methods/mod.rs

@@ -61,15 +61,12 @@
 
 use bind_instead_of_map::BindInsteadOfMap;
 use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
-use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::ty::{contains_ty, implements_trait, is_copy, is_type_diagnostic_item};
 use clippy_utils::{
     contains_return, get_trait_def_id, in_macro, iter_input_pats, match_qpath, method_calls, paths, return_ty,
     SpanlessEq,
 };
 use if_chain::if_chain;
-use rustc_ast::ast;
-use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::{TraitItem, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
@@ -1978,34 +1975,6 @@ macro_rules! lint_with_both_lhs_and_rhs {
     lint_with_both_lhs_and_rhs!(chars_last_cmp_with_unwrap::check, cx, info);
 }
 
-fn get_hint_if_single_char_arg(
-    cx: &LateContext<'_>,
-    arg: &hir::Expr<'_>,
-    applicability: &mut Applicability,
-) -> Option<String> {
-    if_chain! {
-        if let hir::ExprKind::Lit(lit) = &arg.kind;
-        if let ast::LitKind::Str(r, style) = lit.node;
-        let string = r.as_str();
-        if string.chars().count() == 1;
-        then {
-            let snip = snippet_with_applicability(cx, arg.span, &string, applicability);
-            let ch = if let ast::StrStyle::Raw(nhash) = style {
-                let nhash = nhash as usize;
-                // for raw string: r##"a"##
-                &snip[(nhash + 2)..(snip.len() - 1 - nhash)]
-            } else {
-                // for regular string: "a"
-                &snip[1..(snip.len() - 1)]
-            };
-            let hint = format!("'{}'", if ch == "'" { "\\'" } else { ch });
-            Some(hint)
-        } else {
-            None
-        }
-    }
-}
-
 const FN_HEADER: hir::FnHeader = hir::FnHeader {
     unsafety: hir::Unsafety::Normal,
     constness: hir::Constness::NotConst,

clippy_lints/src/methods/single_char_insert_string.rs

@@ -1,4 +1,4 @@
-use crate::methods::get_hint_if_single_char_arg;
+use crate::methods::utils::get_hint_if_single_char_arg;
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_with_applicability;
 use rustc_errors::Applicability;

clippy_lints/src/methods/single_char_pattern.rs

@@ -1,4 +1,4 @@
-use crate::methods::get_hint_if_single_char_arg;
+use crate::methods::utils::get_hint_if_single_char_arg;
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use if_chain::if_chain;
 use rustc_errors::Applicability;

clippy_lints/src/methods/single_char_push_string.rs

@@ -1,4 +1,4 @@
-use crate::methods::get_hint_if_single_char_arg;
+use crate::methods::utils::get_hint_if_single_char_arg;
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_with_applicability;
 use rustc_errors::Applicability;

clippy_lints/src/methods/utils.rs

@@ -1,11 +1,15 @@
+use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::ty::is_type_diagnostic_item;
+use if_chain::if_chain;
+use rustc_ast::ast;
+use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
 use rustc_middle::ty;
 use rustc_middle::ty::Ty;
 use rustc_span::symbol::sym;
 
-pub fn derefs_to_slice<'tcx>(
+pub(super) fn derefs_to_slice<'tcx>(
     cx: &LateContext<'tcx>,
     expr: &'tcx hir::Expr<'tcx>,
     ty: Ty<'tcx>,
@@ -44,3 +48,31 @@ fn may_slice<'a>(cx: &LateContext<'a>, ty: Ty<'a>) -> bool {
         }
     }
 }
+
+pub(super) fn get_hint_if_single_char_arg(
+    cx: &LateContext<'_>,
+    arg: &hir::Expr<'_>,
+    applicability: &mut Applicability,
+) -> Option<String> {
+    if_chain! {
+        if let hir::ExprKind::Lit(lit) = &arg.kind;
+        if let ast::LitKind::Str(r, style) = lit.node;
+        let string = r.as_str();
+        if string.chars().count() == 1;
+        then {
+            let snip = snippet_with_applicability(cx, arg.span, &string, applicability);
+            let ch = if let ast::StrStyle::Raw(nhash) = style {
+                let nhash = nhash as usize;
+                // for raw string: r##"a"##
+                &snip[(nhash + 2)..(snip.len() - 1 - nhash)]
+            } else {
+                // for regular string: "a"
+                &snip[1..(snip.len() - 1)]
+            };
+            let hint = format!("'{}'", if ch == "'" { "\\'" } else { ch });
+            Some(hint)
+        } else {
+            None
+        }
+    }
+}