remove unnecessary check and move to_camel_case to str_util

Author: jonboh

clippy_lints/foo.txt

@@ -2,7 +2,7 @@
 
 use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_hir};
 use clippy_utils::source::is_present_in_source;
-use clippy_utils::str_utils::{camel_case_split, count_match_end, count_match_start, to_snake_case};
+use clippy_utils::str_utils::{camel_case_split, count_match_end, count_match_start, to_camel_case, to_snake_case};
 use rustc_hir::{EnumDef, FieldDef, Item, ItemKind, OwnerId, Variant, VariantData};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
@@ -165,48 +165,20 @@ impl_lint_pass!(ItemNameRepetitions => [
     MODULE_INCEPTION
 ]);
 
-fn is_snake_case(name: &str) -> bool {
-    name.chars().all(|c| !c.is_uppercase() || c == '_')
-}
-
 #[must_use]
 fn have_no_extra_prefix(prefixes: &[&str]) -> bool {
     prefixes.iter().all(|p| p == &"" || p == &"_")
 }
 
-#[must_use]
-fn to_camel_case(item_name: &str) -> String {
-    let mut s = String::new();
-    let mut up = true;
-    for c in item_name.chars() {
-        if c.is_uppercase() {
-            // we only turn snake case text into CamelCase
-            return item_name.to_string();
-        }
-        if c == '_' {
-            up = true;
-            continue;
-        }
-        if up {
-            up = false;
-            s.extend(c.to_uppercase());
-        } else {
-            s.push(c);
-        }
-    }
-    s
-}
-
 fn check_fields(cx: &LateContext<'_>, threshold: u64, fields: &[FieldDef<'_>], item_name: &str, item_span: Span) {
     if (fields.len() as u64) < threshold {
         return;
     }
 
+    let item_name_snake = to_snake_case(item_name);
     for field in fields {
-        if is_snake_case(field.ident.name.as_str()) {
-            check_struct_start(cx, item_name, field);
-            check_struct_end(cx, item_name, field);
-        }
+        check_struct_start(cx, &item_name_snake, field);
+        check_struct_end(cx, &item_name_snake, field);
     }
 
     let mut pre: Vec<&str> = match fields.get(0) {
@@ -255,10 +227,9 @@ fn check_fields(cx: &LateContext<'_>, threshold: u64, fields: &[FieldDef<'_>], i
 }
 
 fn check_struct_start(cx: &LateContext<'_>, item_name: &str, field: &FieldDef<'_>) {
-    let item_name_snake = to_snake_case(item_name);
     let name = field.ident.name.as_str();
 
-    if name.starts_with(&item_name_snake) {
+    if name.starts_with(item_name) {
         span_lint_hir(
             cx,
             STRUCT_FIELD_NAMES,
@@ -270,10 +241,9 @@ fn check_struct_start(cx: &LateContext<'_>, item_name: &str, field: &FieldDef<'_
 }
 
 fn check_struct_end(cx: &LateContext<'_>, item_name: &str, field: &FieldDef<'_>) {
-    let item_name_snake = to_snake_case(item_name);
     let name = field.ident.name.as_str();
 
-    if name.ends_with(&item_name_snake) {
+    if name.ends_with(item_name) {
         span_lint_hir(
             cx,
             STRUCT_FIELD_NAMES,

clippy_lints/src/item_name_repetitions.rs

@@ -259,6 +259,35 @@ pub fn to_snake_case(name: &str) -> String {
     }
     s
 }
+/// Returns a `CamelCase` version of the input
+/// ```
+/// use clippy_utils::str_utils::to_camel_case;
+/// assert_eq!(to_snake_case("abc_def"), "AbcDef");
+/// assert_eq!(to_snake_case("a_b_c_d"), "ABCD");
+/// assert_eq!(to_snake_case("abc_d_d"), "AbcDD");
+/// assert_eq!(to_snake_case("abc1_d_d"), "Abc1DD");
+/// ```
+pub fn to_camel_case(item_name: &str) -> String {
+    let mut s = String::new();
+    let mut up = true;
+    for c in item_name.chars() {
+        if c.is_uppercase() {
+            // we only turn snake case text into CamelCase
+            return item_name.to_string();
+        }
+        if c == '_' {
+            up = true;
+            continue;
+        }
+        if up {
+            up = false;
+            s.extend(c.to_uppercase());
+        } else {
+            s.push(c);
+        }
+    }
+    s
+}
 
 #[cfg(test)]
 mod test {