pulled strings passes together, added more tests

src/lib.rs

@@ -56,7 +56,6 @@ pub fn plugin_registrar(reg: &mut Registry) {
     reg.register_lint_pass(box misc::ModuloOne as LintPassObject);
     reg.register_lint_pass(box unicode::Unicode as LintPassObject);
     reg.register_lint_pass(box strings::StringAdd as LintPassObject);
-    reg.register_lint_pass(box strings::StringAddAssign as LintPassObject);
     reg.register_lint_pass(box returns::ReturnPass as LintPassObject);
     reg.register_lint_pass(box methods::MethodsPass as LintPassObject);
 

src/strings.rs

@@ -28,7 +28,7 @@ pub struct StringAdd;
 
 impl LintPass for StringAdd {
     fn get_lints(&self) -> LintArray {
-        lint_array!(STRING_ADD)
+        lint_array!(STRING_ADD, STRING_ADD_ASSIGN)
     }
 
     fn check_expr(&mut self, cx: &Context, e: &Expr) {
@@ -50,21 +50,7 @@ impl LintPass for StringAdd {
                         "you add something to a string. \
                         Consider using `String::push_str()` instead.")
             }
-        }
-    }
-}
-            
-
-#[derive(Copy, Clone)]
-pub struct StringAddAssign;
-
-impl LintPass for StringAddAssign {
-    fn get_lints(&self) -> LintArray {
-        lint_array!(STRING_ADD_ASSIGN)
-    }
-
-    fn check_expr(&mut self, cx: &Context, e: &Expr) {
-        if let &ExprAssign(ref target, ref  src) = &e.node {
+        } else if let &ExprAssign(ref target, ref  src) = &e.node {
             if is_string(cx, target) && is_add(src, target) {
                 span_lint(cx, STRING_ADD_ASSIGN, e.span,
                     "you assign the result of adding something to this string. \

tests/compile-fail/strings.rs

@@ -1,9 +1,37 @@
 #![feature(plugin)]
 #![plugin(clippy)]
 
-#![deny(string_add_assign)]
-#![deny(string_add)]
-fn main() {
+#[deny(string_add)]
+#[allow(string_add_assign)]
+fn add_only() { // ignores assignment distinction
+	let mut x = "".to_owned();
+
+    for _ in (1..3) {
+        x = x + "."; //~ERROR you add something to a string.
+    }
+    
+    let y = "".to_owned();
+    let z = y + "..."; //~ERROR you add something to a string.
+    
+    assert_eq!(&x, &z);
+}
+
+#[deny(string_add_assign)]
+fn add_assign_only() {
+	let mut x = "".to_owned();
+
+    for _ in (1..3) {
+        x = x + "."; //~ERROR you assign the result of adding something to this string.
+    }
+    
+    let y = "".to_owned();
+    let z = y + "...";
+    
+    assert_eq!(&x, &z);
+}
+
+#[deny(string_add, string_add_assign)]
+fn both() {
     let mut x = "".to_owned();
 
     for _ in (1..3) {
@@ -15,3 +43,14 @@ fn main() {
     
     assert_eq!(&x, &z);
 }
+
+fn main() {
+	add_only();
+	add_assign_only();
+	both();
+	
+	// the add is only caught for String
+	let mut x = 1;
+	x = x + 1;
+	assert_eq!(2, x);
+}