Address suggestions in PR review

CHANGELOG.md

@@ -22,7 +22,7 @@ Current beta, release 2020-11-19
 * [`map_err_ignore`] [#5998](https://github.com/rust-lang/rust-clippy/pull/5998)
 * [`rc_buffer`] [#6044](https://github.com/rust-lang/rust-clippy/pull/6044)
 * [`to_string_in_display`] [#5831](https://github.com/rust-lang/rust-clippy/pull/5831)
-* [`single_char_push_str`] [#5881](https://github.com/rust-lang/rust-clippy/pull/5881)
+* `single_char_push_str` [#5881](https://github.com/rust-lang/rust-clippy/pull/5881)
 
 ### Moves and Deprecations
 

clippy_lints/src/lib.rs

@@ -1958,6 +1958,7 @@ pub fn register_renamed(ls: &mut rustc_lint::LintStore) {
     ls.register_renamed("clippy::for_loop_over_result", "clippy::for_loops_over_fallibles");
     ls.register_renamed("clippy::identity_conversion", "clippy::useless_conversion");
     ls.register_renamed("clippy::zero_width_space", "clippy::invisible_characters");
+    ls.register_renamed("clippy::single_char_push_str", "clippy::single_char_add_str");
 }
 
 // only exists to let the dogfood integration test works.

clippy_lints/src/methods/mod.rs

@@ -3266,7 +3266,7 @@ fn lint_single_char_insert_string(cx: &LateContext<'_>, expr: &hir::Expr<'_>, ar
     if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[2], &mut applicability) {
         let base_string_snippet =
             snippet_with_applicability(cx, args[0].span.source_callsite(), "_", &mut applicability);
-        let pos_arg = snippet(cx, args[1].span, "..");
+        let pos_arg = snippet_with_applicability(cx, args[1].span, "..", &mut applicability);
         let sugg = format!("{}.insert({}, {})", base_string_snippet, pos_arg, extension_string);
         span_lint_and_sugg(
             cx,

tests/ui/single_char_add_str.fixed

@@ -38,6 +38,8 @@ fn main() {
     string.insert(x, 'a');
     const Y: usize = 1;
     string.insert(Y, 'a');
+    string.insert(Y, '"');
+    string.insert(Y, '\'');
 
     get_string!().insert(1, '?');
 }

tests/ui/single_char_add_str.rs

@@ -38,6 +38,8 @@ fn main() {
     string.insert_str(x, r##"a"##);
     const Y: usize = 1;
     string.insert_str(Y, r##"a"##);
+    string.insert_str(Y, r##"""##);
+    string.insert_str(Y, r##"'"##);
 
     get_string!().insert_str(1, "?");
 }

tests/ui/single_char_add_str.stderr

@@ -72,11 +72,23 @@ error: calling `insert_str()` using a single-character string literal
 LL |     string.insert_str(Y, r##"a"##);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(Y, 'a')`
 
+error: calling `insert_str()` using a single-character string literal
+  --> $DIR/single_char_add_str.rs:41:5
+   |
+LL |     string.insert_str(Y, r##"""##);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(Y, '"')`
+
 error: calling `insert_str()` using a single-character string literal
   --> $DIR/single_char_add_str.rs:42:5
    |
+LL |     string.insert_str(Y, r##"'"##);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(Y, '/'')`
+
+error: calling `insert_str()` using a single-character string literal
+  --> $DIR/single_char_add_str.rs:44:5
+   |
 LL |     get_string!().insert_str(1, "?");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `get_string!().insert(1, '?')`
 
-error: aborting due to 13 previous errors
+error: aborting due to 15 previous errors