fix TrailingWhitespace when using line breaks in macros arguments (rust-lang#3768)

Author: rchaser53

src/formatting.rs

@@ -188,7 +188,7 @@ impl<'a, T: FormatHandler + 'a> FormatContext<'a, T> {
         format_lines(
             &mut visitor.buffer,
             &path,
-            &visitor.skipped_range,
+            &visitor.skipped_range.borrow(),
             &self.config,
             &self.report,
         );
@@ -203,7 +203,7 @@ impl<'a, T: FormatHandler + 'a> FormatContext<'a, T> {
             self.report.add_macro_format_failure();
         }
         self.report
-            .add_non_formatted_ranges(visitor.skipped_range.clone());
+            .add_non_formatted_ranges(visitor.skipped_range.borrow().clone());
 
         self.handler.handle_formatted_file(
             self.parse_session.source_map(),

src/macros.rs

@@ -181,6 +181,11 @@ fn return_macro_parse_failure_fallback(
         return trim_left_preserve_layout(context.snippet(span), indent, &context.config);
     }
 
+    context.skipped_range.borrow_mut().push((
+        context.source_map.lookup_line(span.lo()).unwrap().line,
+        context.source_map.lookup_line(span.hi()).unwrap().line,
+    ));
+
     // Return the snippet unmodified if the macro is not block-like
     Some(context.snippet(span).to_owned())
 }

src/rewrite.rs

@@ -1,6 +1,7 @@
 // A generic trait to abstract the rewriting of an element (of the AST).
 
 use std::cell::RefCell;
+use std::rc::Rc;
 
 use syntax::parse::ParseSess;
 use syntax::ptr;
@@ -41,6 +42,7 @@ pub(crate) struct RewriteContext<'a> {
     pub(crate) macro_rewrite_failure: RefCell<bool>,
     pub(crate) report: FormatReport,
     pub(crate) skip_context: SkipContext,
+    pub(crate) skipped_range: Rc<RefCell<Vec<(usize, usize)>>>,
 }
 
 impl<'a> RewriteContext<'a> {

src/visitor.rs

@@ -1,4 +1,5 @@
 use std::cell::RefCell;
+use std::rc::Rc;
 
 use syntax::parse::ParseSess;
 use syntax::source_map::{self, BytePos, Pos, SourceMap, Span};
@@ -65,7 +66,7 @@ pub(crate) struct FmtVisitor<'a> {
     pub(crate) line_number: usize,
     /// List of 1-based line ranges which were annotated with skip
     /// Both bounds are inclusifs.
-    pub(crate) skipped_range: Vec<(usize, usize)>,
+    pub(crate) skipped_range: Rc<RefCell<Vec<(usize, usize)>>>,
     pub(crate) macro_rewrite_failure: bool,
     pub(crate) report: FormatReport,
     pub(crate) skip_context: SkipContext,
@@ -652,7 +653,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
         let lo = std::cmp::min(attrs_end + 1, first_line);
         self.push_rewrite_inner(item_span, None);
         let hi = self.line_number + 1;
-        self.skipped_range.push((lo, hi));
+        self.skipped_range.borrow_mut().push((lo, hi));
     }
 
     pub(crate) fn from_context(ctx: &'a RewriteContext<'_>) -> FmtVisitor<'a> {
@@ -684,7 +685,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
             is_if_else_block: false,
             snippet_provider,
             line_number: 0,
-            skipped_range: vec![],
+            skipped_range: Rc::new(RefCell::new(vec![])),
             macro_rewrite_failure: false,
             report,
             skip_context: Default::default(),
@@ -877,6 +878,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
             macro_rewrite_failure: RefCell::new(false),
             report: self.report.clone(),
             skip_context: self.skip_context.clone(),
+            skipped_range: self.skipped_range.clone(),
         }
     }
 }

tests/target/issue-2916.rs

@@ -0,0 +1,2 @@
+a_macro!(name<Param1, Param2>, 
+);