fix 'fails with conditional paths that include' (#3955)

Author: topecongiro

src/missed_spans.rs

@@ -95,7 +95,9 @@ impl<'a> FmtVisitor<'a> {
         let snippet = self.snippet(span);
 
         // Do nothing for spaces in the beginning of the file
-        if start == BytePos(0) && end.0 as usize == snippet.len() && snippet.trim().is_empty() {
+        let is_start_span =
+            (start == BytePos(0) && end.0 as usize == snippet.len()) || self.is_start_span(span);
+        if is_start_span && snippet.trim().is_empty() {
             return;
         }
 

src/spanned.rs

@@ -31,7 +31,12 @@ macro_rules! span_with_attrs_lo_hi {
         if attrs.is_empty() {
             mk_sp($lo, $hi)
         } else {
-            mk_sp(attrs[0].span.lo(), $hi)
+            // this path is already gone at latest rust-ap-* 627.0.0
+            if attrs[0].item.path.to_string() == "warn_directory_ownership" {
+                mk_sp($lo, $hi)
+            } else {
+                mk_sp(attrs[0].span.lo(), $hi)
+            }
         }
     }};
 }

src/visitor.rs

@@ -46,6 +46,10 @@ impl SnippetProvider {
         Some(&self.big_snippet[start_index..end_index])
     }
 
+    pub(crate) fn is_start_span(&self, span: Span) -> bool {
+        span.lo().to_usize() == self.start_pos
+    }
+
     pub(crate) fn new(start_pos: BytePos, end_pos: BytePos, big_snippet: Rc<String>) -> Self {
         let start_pos = start_pos.to_usize();
         let end_pos = end_pos.to_usize();
@@ -751,6 +755,10 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
         self.opt_snippet(span).unwrap()
     }
 
+    pub(crate) fn is_start_span(&'b self, span: Span) -> bool {
+        self.snippet_provider.is_start_span(span)
+    }
+
     // Returns true if we should skip the following item.
     pub(crate) fn visit_attrs(&mut self, attrs: &[ast::Attribute], style: ast::AttrStyle) -> bool {
         for attr in attrs {

tests/source/issue-3933/imp-a.rs

@@ -0,0 +1,3 @@
+  mod utils;
+pub 
+  struct A;

tests/source/issue-3933/imp-b.rs

@@ -0,0 +1 @@
+pub struct B;

tests/source/issue-3933/lib.rs

@@ -0,0 +1,4 @@
+#[cfg_attr(windows, path = "imp-a.rs" )]
+  #[cfg_attr(not(windows), path = "imp-b.rs")]
+mod   imp;
+  pub use imp::A;

tests/source/issue-3933/utils.rs

@@ -0,0 +1,4 @@
+  pub fn fuga() {
+
+
+}

tests/target/issue-3933/imp-a.rs

@@ -0,0 +1,2 @@
+mod utils;
+pub struct A;

tests/target/issue-3933/imp-b.rs

@@ -0,0 +1 @@
+pub struct B;

tests/target/issue-3933/lib.rs

@@ -0,0 +1,4 @@
+#[cfg_attr(windows, path = "imp-a.rs")]
+#[cfg_attr(not(windows), path = "imp-b.rs")]
+mod imp;
+pub use imp::A;