Merge pull request #1945 from topecongiro/issue-1095

Exclude prefix colon from span when rewriting comment

Author: nrc

src/items.rs

@@ -2313,35 +2313,45 @@ fn rewrite_generics_inner(
 ) -> Option<String> {
     // FIXME: convert bounds to where clauses where they get too big or if
     // there is a where clause at all.
-    let lifetimes: &[_] = &generics.lifetimes;
-    let tys: &[_] = &generics.ty_params;
-    if lifetimes.is_empty() && tys.is_empty() {
-        return Some(String::new());
-    }
 
-    // Strings for the generics.
-    let lt_strs = lifetimes.iter().map(|lt| lt.rewrite(context, shape));
-    let ty_strs = tys.iter().map(|ty_param| ty_param.rewrite(context, shape));
+    // Wrapper type
+    enum GenericsArg<'a> {
+        Lifetime(&'a ast::LifetimeDef),
+        TyParam(&'a ast::TyParam),
+    }
+    impl<'a> Rewrite for GenericsArg<'a> {
+        fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
+            match *self {
+                GenericsArg::Lifetime(ref lifetime) => lifetime.rewrite(context, shape),
+                GenericsArg::TyParam(ref ty) => ty.rewrite(context, shape),
+            }
+        }
+    }
+    impl<'a> Spanned for GenericsArg<'a> {
+        fn span(&self) -> Span {
+            match *self {
+                GenericsArg::Lifetime(ref lifetime) => lifetime.span(),
+                GenericsArg::TyParam(ref ty) => ty.span(),
+            }
+        }
+    }
 
-    // Extract comments between generics.
-    let lt_spans = lifetimes.iter().map(|l| {
-        let hi = if l.bounds.is_empty() {
-            l.lifetime.span.hi()
-        } else {
-            l.bounds[l.bounds.len() - 1].span.hi()
-        };
-        mk_sp(l.lifetime.span.lo(), hi)
-    });
-    let ty_spans = tys.iter().map(|ty| ty.span());
+    if generics.lifetimes.is_empty() && generics.ty_params.is_empty() {
+        return Some(String::new());
+    }
 
+    let generics_args = generics
+        .lifetimes
+        .iter()
+        .map(|lt| GenericsArg::Lifetime(lt))
+        .chain(generics.ty_params.iter().map(|ty| GenericsArg::TyParam(ty)));
     let items = itemize_list(
         context.codemap,
-        lt_spans.chain(ty_spans).zip(lt_strs.chain(ty_strs)),
+        generics_args,
         ">",
-        |&(sp, _)| sp.lo(),
-        |&(sp, _)| sp.hi(),
-        // FIXME: don't clone
-        |&(_, ref str)| str.clone(),
+        |arg| arg.span().lo(),
+        |arg| arg.span().hi(),
+        |arg| arg.rewrite(context, shape),
         context.codemap.span_after(span, "<"),
         span.hi(),
         false,

src/lib.rs

@@ -217,6 +217,17 @@ impl Spanned for ast::TyParamBound {
     }
 }
 
+impl Spanned for ast::LifetimeDef {
+    fn span(&self) -> Span {
+        let hi = if self.bounds.is_empty() {
+            self.lifetime.span.hi()
+        } else {
+            self.bounds[self.bounds.len() - 1].span.hi()
+        };
+        mk_sp(self.lifetime.span.lo(), hi)
+    }
+}
+
 impl Spanned for MacroArg {
     fn span(&self) -> Span {
         match *self {

src/lists.rs

@@ -641,7 +641,7 @@ where
             self.prev_span_end = (self.get_hi)(&item) + BytePos(comment_end as u32);
             let post_snippet = post_snippet[..comment_end].trim();
 
-            let post_snippet_trimmed = if post_snippet.starts_with(',') {
+            let post_snippet_trimmed = if post_snippet.starts_with(|c| c == ',' || c == ':') {
                 post_snippet[1..].trim_matches(white_space)
             } else if post_snippet.ends_with(',') {
                 post_snippet[..(post_snippet.len() - 1)].trim_matches(white_space)

src/types.rs

@@ -584,11 +584,10 @@ impl Rewrite for ast::TyParam {
     fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
         let mut result = String::with_capacity(128);
         // FIXME: If there are more than one attributes, this will force multiline.
-        let attr_str = match (&*self.attrs).rewrite(context, shape) {
-            Some(ref rw) if !rw.is_empty() => format!("{} ", rw),
-            _ => String::new(),
-        };
-        result.push_str(&attr_str);
+        match self.attrs.rewrite(context, shape) {
+            Some(ref rw) if !rw.is_empty() => result.push_str(&format!("{} ", rw)),
+            _ => (),
+        }
         result.push_str(&self.ident.to_string());
         if !self.bounds.is_empty() {
             result.push_str(type_bound_colon(context));

tests/source/structs.rs

@@ -15,6 +15,11 @@ pub struct Foo {
     pub i: TypeForPublicField
 }
 
+// #1095
+struct S<T: /* comment */> {
+    t: T,
+}
+
 // #1029
 pub struct Foo {
     #[doc(hidden)]

tests/target/structs.rs

@@ -14,6 +14,11 @@ pub struct Foo {
     pub i: TypeForPublicField,
 }
 
+// #1095
+struct S<T /* comment */> {
+    t: T,
+}
+
 // #1029
 pub struct Foo {
     #[doc(hidden)]