Rollup merge of rust-lang#37202 - petrochenkov:pretty, r=nrc

Fix some pretty printing tests

Many pretty-printing tests are un-ignored.
Some issues in classification of comments (trailing/isolated) and blank line counting are fixed.
Some comments are printed more carefully.
Some minor refactoring in pprust.rs
`no-pretty-expanded` annotations are removed because this is the default now.
`pretty-expanded` annotations are removed from compile-fail tests, they are not tested with pretty-printer.

Closes rust-lang#23623 in favor of more specific rust-lang#37201 and rust-lang#37199
r? @nrc

Author: eddyb

src/libsyntax/parse/lexer/comments.rs

@@ -24,7 +24,7 @@ use str::char_at;
 use std::io::Read;
 use std::usize;
 
-#[derive(Clone, Copy, PartialEq)]
+#[derive(Clone, Copy, PartialEq, Debug)]
 pub enum CommentStyle {
     /// No code on either side of each line of the comment
     Isolated,
@@ -155,14 +155,13 @@ fn push_blank_line_comment(rdr: &StringReader, comments: &mut Vec<Comment>) {
 
 fn consume_whitespace_counting_blank_lines(rdr: &mut StringReader, comments: &mut Vec<Comment>) {
     while is_pattern_whitespace(rdr.ch) && !rdr.is_eof() {
-        if rdr.col == CharPos(0) && rdr.ch_is('\n') {
+        if rdr.ch_is('\n') {
             push_blank_line_comment(rdr, &mut *comments);
         }
         rdr.bump();
     }
 }
 
-
 fn read_shebang_comment(rdr: &mut StringReader,
                         code_to_the_left: bool,
                         comments: &mut Vec<Comment>) {
@@ -317,14 +316,22 @@ fn read_block_comment(rdr: &mut StringReader,
 }
 
 
-fn consume_comment(rdr: &mut StringReader, code_to_the_left: bool, comments: &mut Vec<Comment>) {
+fn consume_comment(rdr: &mut StringReader,
+                   comments: &mut Vec<Comment>,
+                   code_to_the_left: &mut bool,
+                   anything_to_the_left: &mut bool) {
     debug!(">>> consume comment");
     if rdr.ch_is('/') && rdr.nextch_is('/') {
-        read_line_comments(rdr, code_to_the_left, comments);
+        read_line_comments(rdr, *code_to_the_left, comments);
+        *code_to_the_left = false;
+        *anything_to_the_left = false;
     } else if rdr.ch_is('/') && rdr.nextch_is('*') {
-        read_block_comment(rdr, code_to_the_left, comments);
+        read_block_comment(rdr, *code_to_the_left, comments);
+        *anything_to_the_left = true;
     } else if rdr.ch_is('#') && rdr.nextch_is('!') {
-        read_shebang_comment(rdr, code_to_the_left, comments);
+        read_shebang_comment(rdr, *code_to_the_left, comments);
+        *code_to_the_left = false;
+        *anything_to_the_left = false;
     } else {
         panic!();
     }
@@ -352,23 +359,29 @@ pub fn gather_comments_and_literals(span_diagnostic: &errors::Handler,
 
     let mut comments: Vec<Comment> = Vec::new();
     let mut literals: Vec<Literal> = Vec::new();
-    let mut first_read: bool = true;
+    let mut code_to_the_left = false; // Only code
+    let mut anything_to_the_left = false; // Code or comments
     while !rdr.is_eof() {
         loop {
-            let mut code_to_the_left = !first_read;
+            // Eat all the whitespace and count blank lines.
             rdr.consume_non_eol_whitespace();
             if rdr.ch_is('\n') {
-                code_to_the_left = false;
+                if anything_to_the_left {
+                    rdr.bump(); // The line is not blank, do not count.
+                }
                 consume_whitespace_counting_blank_lines(&mut rdr, &mut comments);
+                code_to_the_left = false;
+                anything_to_the_left = false;
             }
-            while rdr.peeking_at_comment() {
-                consume_comment(&mut rdr, code_to_the_left, &mut comments);
-                consume_whitespace_counting_blank_lines(&mut rdr, &mut comments);
+            // Eat one comment group
+            if rdr.peeking_at_comment() {
+                consume_comment(&mut rdr, &mut comments,
+                                &mut code_to_the_left, &mut anything_to_the_left);
+            } else {
+                break
             }
-            break;
         }
 
-
         let bstart = rdr.pos;
         rdr.next_token();
         // discard, and look ahead; we're working with internal state
@@ -384,7 +397,8 @@ pub fn gather_comments_and_literals(span_diagnostic: &errors::Handler,
         } else {
             debug!("tok: {}", pprust::token_to_string(&tok));
         }
-        first_read = false;
+        code_to_the_left = true;
+        anything_to_the_left = true;
     }
 
     (comments, literals)

src/libsyntax/print/pprust.rs

@@ -545,15 +545,12 @@ pub trait PrintState<'a> {
     }
 
     fn maybe_print_comment(&mut self, pos: BytePos) -> io::Result<()> {
-        loop {
-            match self.next_comment() {
-                Some(ref cmnt) => {
-                    if (*cmnt).pos < pos {
-                        try!(self.print_comment(cmnt));
-                        self.cur_cmnt_and_lit().cur_cmnt += 1;
-                    } else { break; }
-                }
-                _ => break
+        while let Some(ref cmnt) = self.next_comment() {
+            if cmnt.pos < pos {
+                try!(self.print_comment(cmnt));
+                self.cur_cmnt_and_lit().cur_cmnt += 1;
+            } else {
+                break
             }
         }
         Ok(())
@@ -581,7 +578,9 @@ pub trait PrintState<'a> {
                 Ok(())
             }
             comments::Trailing => {
-                try!(word(self.writer(), " "));
+                if !self.is_bol() {
+                    try!(word(self.writer(), " "));
+                }
                 if cmnt.lines.len() == 1 {
                     try!(word(self.writer(), &cmnt.lines[0]));
                     hardbreak(self.writer())
@@ -1716,6 +1715,7 @@ impl<'a> State<'a> {
         for (i, st) in blk.stmts.iter().enumerate() {
             match st.node {
                 ast::StmtKind::Expr(ref expr) if i == blk.stmts.len() - 1 => {
+                    try!(self.maybe_print_comment(st.span.lo));
                     try!(self.space_if_not_bol());
                     try!(self.print_expr_outer_attr_style(&expr, false));
                     try!(self.maybe_print_trailing_comment(expr.span, Some(blk.span.hi)));
@@ -2605,6 +2605,7 @@ impl<'a> State<'a> {
         }
         try!(self.cbox(INDENT_UNIT));
         try!(self.ibox(0));
+        try!(self.maybe_print_comment(arm.pats[0].span.lo));
         try!(self.print_outer_attributes(&arm.attrs));
         let mut first = true;
         for p in &arm.pats {
@@ -3010,15 +3011,11 @@ impl<'a> State<'a> {
             _ => return Ok(())
         };
         if let Some(ref cmnt) = self.next_comment() {
-            if (*cmnt).style != comments::Trailing { return Ok(()) }
+            if cmnt.style != comments::Trailing { return Ok(()) }
             let span_line = cm.lookup_char_pos(span.hi);
-            let comment_line = cm.lookup_char_pos((*cmnt).pos);
-            let mut next = (*cmnt).pos + BytePos(1);
-            if let Some(p) = next_pos {
-                next = p;
-            }
-            if span.hi < (*cmnt).pos && (*cmnt).pos < next &&
-               span_line.line == comment_line.line {
+            let comment_line = cm.lookup_char_pos(cmnt.pos);
+            let next = next_pos.unwrap_or(cmnt.pos + BytePos(1));
+            if span.hi < cmnt.pos && cmnt.pos < next && span_line.line == comment_line.line {
                 self.print_comment(cmnt)?;
                 self.cur_cmnt_and_lit.cur_cmnt += 1;
             }

src/test/compile-fail/borrowck/borrowck-use-uninitialized-in-cast.rs

@@ -12,8 +12,6 @@
 // The problem was specified to casting to `*`, as creating unsafe
 // pointers was not being fully checked. Issue #20791.
 
-// pretty-expanded FIXME #23616
-
 fn main() {
     let x: &i32;
     let y = x as *const i32; //~ ERROR use of possibly uninitialized variable: `*x`

src/test/compile-fail/coherence-cow.rs

@@ -12,8 +12,6 @@
 
 // aux-build:coherence_lib.rs
 
-// pretty-expanded FIXME #23616
-
 // Test that the `Pair` type reports an error if it contains type
 // parameters, even when they are covered by local types. This test
 // was originally intended to test the opposite, but the rules changed

src/test/compile-fail/coherence-vec-local-2.rs

@@ -13,8 +13,6 @@
 
 // aux-build:coherence_lib.rs
 
-// pretty-expanded FIXME #23616
-
 extern crate coherence_lib as lib;
 use lib::Remote;
 

src/test/compile-fail/coherence-vec-local.rs

@@ -13,8 +13,6 @@
 
 // aux-build:coherence_lib.rs
 
-// pretty-expanded FIXME #23616
-
 extern crate coherence_lib as lib;
 use lib::Remote;
 

src/test/compile-fail/issue-13352.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// pretty-expanded FIXME #23616
-
 fn foo(_: Box<FnMut()>) {}
 
 fn main() {

src/test/compile-fail/issue-19482.rs

@@ -11,8 +11,6 @@
 // Test that a partially specified trait object with unspecified associated
 // type does not type-check.
 
-// pretty-expanded FIXME #23616
-
 trait Foo {
     type A;
 

src/test/compile-fail/meta-expected-error-correct-rev.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 // revisions: a
-// pretty-expanded FIXME #23616
 
 // Counterpart to `meta-expected-error-wrong-rev.rs`
 

src/test/compile-fail/meta-expected-error-wrong-rev.rs

@@ -10,7 +10,6 @@
 
 // revisions: a
 // should-fail
-// pretty-expanded FIXME #23616
 
 // This is a "meta-test" of the compilertest framework itself.  In
 // particular, it includes the right error message, but the message