Auto merge of #4006 - phansch:fix_module_name_repetitions_fp, r=flip1995

Fix false positive in module_name_repetitions lint

This lint was triggering on modules inside expanded attrs, like
for example `#[cfg(test)]` and possibly more.

It was not reporting a location in #3892 because `span.lo()` and `span.hi()` both were 0.

Fixes #3892

changelog: Fix false positive in `module_name_repetitions` lint

clippy_lints/src/attrs.rs

@@ -2,8 +2,8 @@
 
 use crate::reexport::*;
 use crate::utils::{
-    in_macro, last_line_of_span, paths, snippet_opt, span_lint, span_lint_and_sugg, span_lint_and_then,
-    without_block_comments,
+    in_macro, is_present_in_source, last_line_of_span, paths, snippet_opt, span_lint, span_lint_and_sugg,
+    span_lint_and_then, without_block_comments,
 };
 use if_chain::if_chain;
 use rustc::hir::*;
@@ -481,20 +481,6 @@ fn is_word(nmi: &NestedMetaItem, expected: &str) -> bool {
     }
 }
 
-// If the snippet is empty, it's an attribute that was inserted during macro
-// expansion and we want to ignore those, because they could come from external
-// sources that the user has no control over.
-// For some reason these attributes don't have any expansion info on them, so
-// we have to check it this way until there is a better way.
-fn is_present_in_source(cx: &LateContext<'_, '_>, span: Span) -> bool {
-    if let Some(snippet) = snippet_opt(cx, span) {
-        if snippet.is_empty() {
-            return false;
-        }
-    }
-    true
-}
-
 declare_lint_pass!(DeprecatedCfgAttribute => [DEPRECATED_CFG_ATTR]);
 
 impl EarlyLintPass for DeprecatedCfgAttribute {

clippy_lints/src/enum_variants.rs

@@ -1,6 +1,6 @@
 //! lint on enum variants that are prefixed or suffixed by the same characters
 
-use crate::utils::{camel_case, in_macro};
+use crate::utils::{camel_case, in_macro, is_present_in_source};
 use crate::utils::{span_help_and_lint, span_lint};
 use rustc::lint::{EarlyContext, EarlyLintPass, Lint, LintArray, LintPass};
 use rustc::{declare_tool_lint, impl_lint_pass};
@@ -244,7 +244,7 @@ impl EarlyLintPass for EnumVariantNames {
         let item_name = item.ident.as_str();
         let item_name_chars = item_name.chars().count();
         let item_camel = to_camel_case(&item_name);
-        if !in_macro(item.span) {
+        if !in_macro(item.span) && is_present_in_source(cx, item.span) {
             if let Some(&(ref mod_name, ref mod_camel)) = self.modules.last() {
                 // constants don't have surrounding modules
                 if !mod_camel.is_empty() {

clippy_lints/src/utils/mod.rs

@@ -93,6 +93,20 @@ pub fn in_macro(span: Span) -> bool {
     span.ctxt().outer().expn_info().is_some()
 }
 
+// If the snippet is empty, it's an attribute that was inserted during macro
+// expansion and we want to ignore those, because they could come from external
+// sources that the user has no control over.
+// For some reason these attributes don't have any expansion info on them, so
+// we have to check it this way until there is a better way.
+pub fn is_present_in_source<'a, T: LintContext<'a>>(cx: &T, span: Span) -> bool {
+    if let Some(snippet) = snippet_opt(cx, span) {
+        if snippet.is_empty() {
+            return false;
+        }
+    }
+    true
+}
+
 /// Checks if type is struct, enum or union type with the given def path.
 pub fn match_type(cx: &LateContext<'_, '_>, ty: Ty<'_>, path: &[&str]) -> bool {
     match ty.sty {

tests/ui/module_name_repetitions.rs

@@ -1,3 +1,5 @@
+// compile-flags: --test
+
 #![warn(clippy::module_name_repetitions)]
 #![allow(dead_code)]
 
@@ -13,4 +15,12 @@ mod foo {
     pub struct Foobar;
 }
 
+#[cfg(test)]
+mod test {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}
+
 fn main() {}

tests/ui/module_name_repetitions.stderr

@@ -1,31 +1,31 @@
 error: item name starts with its containing module's name
-  --> $DIR/module_name_repetitions.rs:6:5
+  --> $DIR/module_name_repetitions.rs:8:5
    |
 LL |     pub fn foo_bar() {}
    |     ^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::module-name-repetitions` implied by `-D warnings`
 
 error: item name ends with its containing module's name
-  --> $DIR/module_name_repetitions.rs:7:5
+  --> $DIR/module_name_repetitions.rs:9:5
    |
 LL |     pub fn bar_foo() {}
    |     ^^^^^^^^^^^^^^^^^^^
 
 error: item name starts with its containing module's name
-  --> $DIR/module_name_repetitions.rs:8:5
+  --> $DIR/module_name_repetitions.rs:10:5
    |
 LL |     pub struct FooCake {}
    |     ^^^^^^^^^^^^^^^^^^^^^
 
 error: item name ends with its containing module's name
-  --> $DIR/module_name_repetitions.rs:9:5
+  --> $DIR/module_name_repetitions.rs:11:5
    |
 LL |     pub enum CakeFoo {}
    |     ^^^^^^^^^^^^^^^^^^^
 
 error: item name starts with its containing module's name
-  --> $DIR/module_name_repetitions.rs:10:5
+  --> $DIR/module_name_repetitions.rs:12:5
    |
 LL |     pub struct Foo7Bar;
    |     ^^^^^^^^^^^^^^^^^^^