deny noop method call

Author: fee1-dead

compiler/rustc_lint/src/noop_method_call.rs

@@ -31,7 +31,7 @@ declare_lint! {
     /// calling `clone` on a `&T` where `T` does not implement clone, actually doesn't do anything
     /// as references are copy. This lint detects these calls and warns the user about them.
     pub NOOP_METHOD_CALL,
-    Warn,
+    Deny,
     "detects the use of well-known noop methods"
 }
 

tests/ui/lint/noop-method-call.rs

@@ -1,6 +1,7 @@
 // check-pass
 
 #![allow(unused)]
+#![warn(noop_method_call)]
 
 use std::borrow::Borrow;
 use std::ops::Deref;

tests/ui/lint/noop-method-call.stderr

@@ -1,58 +1,62 @@
 warning: call to `.clone()` on a reference in this situation does nothing
-  --> $DIR/noop-method-call.rs:15:71
+  --> $DIR/noop-method-call.rs:16:71
    |
 LL |     let non_clone_type_ref_clone: &PlainType<u32> = non_clone_type_ref.clone();
    |                                                                       ^^^^^^^^ unnecessary method call
    |
    = note: the type `PlainType<u32>` does not implement `Clone`, so calling `clone` on `&PlainType<u32>` copies the reference, which does not do anything and can be removed
-   = note: `#[warn(noop_method_call)]` on by default
+note: the lint level is defined here
+  --> $DIR/noop-method-call.rs:4:9
+   |
+LL | #![warn(noop_method_call)]
+   |         ^^^^^^^^^^^^^^^^
 
 warning: using `.clone()` on a double reference, which returns `&CloneType<u32>` instead of cloning the inner type
-  --> $DIR/noop-method-call.rs:22:63
+  --> $DIR/noop-method-call.rs:23:63
    |
 LL |     let clone_type_ref_clone: &CloneType<u32> = clone_type_ref.clone();
    |                                                               ^^^^^^^^
    |
    = note: `#[warn(suspicious_double_ref_op)]` on by default
 
 warning: call to `.deref()` on a reference in this situation does nothing
-  --> $DIR/noop-method-call.rs:26:63
+  --> $DIR/noop-method-call.rs:27:63
    |
 LL |     let non_deref_type_deref: &PlainType<u32> = non_deref_type.deref();
    |                                                               ^^^^^^^^ unnecessary method call
    |
    = note: the type `PlainType<u32>` does not implement `Deref`, so calling `deref` on `&PlainType<u32>` copies the reference, which does not do anything and can be removed
 
 warning: using `.deref()` on a double reference, which returns `&PlainType<u32>` instead of dereferencing the inner type
-  --> $DIR/noop-method-call.rs:30:63
+  --> $DIR/noop-method-call.rs:31:63
    |
 LL |     let non_deref_type_deref: &PlainType<u32> = non_deref_type.deref();
    |                                                               ^^^^^^^^
 
 warning: call to `.borrow()` on a reference in this situation does nothing
-  --> $DIR/noop-method-call.rs:34:66
+  --> $DIR/noop-method-call.rs:35:66
    |
 LL |     let non_borrow_type_borrow: &PlainType<u32> = non_borrow_type.borrow();
    |                                                                  ^^^^^^^^^ unnecessary method call
    |
    = note: the type `PlainType<u32>` does not implement `Borrow`, so calling `borrow` on `&PlainType<u32>` copies the reference, which does not do anything and can be removed
 
 warning: using `.clone()` on a double reference, which returns `&str` instead of cloning the inner type
-  --> $DIR/noop-method-call.rs:42:44
+  --> $DIR/noop-method-call.rs:43:44
    |
 LL |     let _v: Vec<&str> = xs.iter().map(|x| x.clone()).collect(); // could use `*x` instead
    |                                            ^^^^^^^^
 
 warning: call to `.clone()` on a reference in this situation does nothing
-  --> $DIR/noop-method-call.rs:47:19
+  --> $DIR/noop-method-call.rs:48:19
    |
 LL |     non_clone_type.clone();
    |                   ^^^^^^^^ unnecessary method call
    |
    = note: the type `PlainType<T>` does not implement `Clone`, so calling `clone` on `&PlainType<T>` copies the reference, which does not do anything and can be removed
 
 warning: call to `.clone()` on a reference in this situation does nothing
-  --> $DIR/noop-method-call.rs:52:19
+  --> $DIR/noop-method-call.rs:53:19
    |
 LL |     non_clone_type.clone();
    |                   ^^^^^^^^ unnecessary method call