Don't handle renaming imports.

Author: xiongmao86

clippy_lints/src/single_component_use_path.rs

@@ -1,7 +1,7 @@
 use crate::utils::span_lint_and_sugg;
 use rustc_lint::{EarlyLintPass, EarlyContext};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
-use syntax::ast::{Item, ItemKind};
+use syntax::ast::{Item, ItemKind, UseTreeKind};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_span::edition::Edition;
@@ -17,11 +17,11 @@ declare_clippy_lint! {
     /// **Example:**
     /// 
     /// ```rust, ignore
-    /// use bit_vec;
+    /// use regex;
     ///
     /// fn main() {
-    ///     bit_vec::BitVec::new();
-    ///}
+    ///     regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$");
+    /// }
     ///```
     pub SINGLE_COMPONENT_USE_PATH,
     style,
@@ -37,6 +37,7 @@ impl EarlyLintPass for SingleComponentUsePath {
             if let ItemKind::Use(use_tree) = &item.kind;
             if let segments = &use_tree.prefix.segments;
             if segments.len() == 1;
+            if let UseTreeKind::Simple(None, _, _) = use_tree.kind;
             then {
                 span_lint_and_sugg(
                     cx,

tests/ui/single_component_use_path.fixed

@@ -5,6 +5,5 @@
 
 
 fn main() {
-    let version = semver::Version::parse("1.2.3").unwrap();
-    println!("Version: {}", version);
+    regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
 }

tests/ui/single_component_use_path.rs

@@ -2,9 +2,8 @@
 // compile-flags: --edition 2018
 #![warn(clippy::single_component_use_path)]
 
-use semver;
+use regex;
 
 fn main() {
-    let version = semver::Version::parse("1.2.3").unwrap();
-    println!("Version: {}", version);
+    regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
 }

tests/ui/single_component_use_path.stderr

@@ -1,17 +1,10 @@
-error[E0432]: unresolved import `semver`
-  --> $DIR/single_component_use_path.rs:5:5
-   |
-LL | use semver;
-   |     ^^^^^^ no `semver` external crate
-
 error: this import is redundant
   --> $DIR/single_component_use_path.rs:5:1
    |
-LL | use semver;
-   | ^^^^^^^^^^^ help: remove it entirely
+LL | use regex;
+   | ^^^^^^^^^^ help: remove it entirely
    |
    = note: `-D clippy::single-component-use-path` implied by `-D warnings`
 
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0432`.