7 files changed, 200 insertions, 60 deletions

diff --git a/crates/ra_syntax/src/ast.rs b/crates/ra_syntax/src/ast.rs
index 1b2ce921a..a12da5be2 100644
--- a/crates/ra_syntax/src/ast.rs
+++ b/crates/ra_syntax/src/ast.rs
@@ -173,7 +173,7 @@ fn test_doc_comment_single_line_block_strips_suffix_whitespace() {
     .ok()
     .unwrap();
     let module = file.syntax().descendants().find_map(Module::cast).unwrap();
-    assert_eq!("this is mod foo", module.doc_comment_text().unwrap());
+    assert_eq!("this is mod foo ", module.doc_comment_text().unwrap());
 }
 
 #[test]
@@ -191,7 +191,27 @@ fn test_doc_comment_multi_line_block_strips_suffix() {
     .ok()
     .unwrap();
     let module = file.syntax().descendants().find_map(Module::cast).unwrap();
-    assert_eq!("        this\n        is\n        mod foo", module.doc_comment_text().unwrap());
+    assert_eq!(
+        "        this\n        is\n        mod foo\n        ",
+        module.doc_comment_text().unwrap()
+    );
+}
+
+#[test]
+fn test_comments_preserve_trailing_whitespace() {
+    let file = SourceFile::parse(
+        r#"
+/// Representation of a Realm.   
+/// In the specification these are called Realm Records.
+struct Realm {}"#,
+    )
+    .ok()
+    .unwrap();
+    let def = file.syntax().descendants().find_map(StructDef::cast).unwrap();
+    assert_eq!(
+        "Representation of a Realm.   \nIn the specification these are called Realm Records.",
+        def.doc_comment_text().unwrap()
+    );
 }
 
 #[test]
diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index 00422ea91..3d5f18bfa 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -77,7 +77,7 @@ pub fn tuple_struct_pat(
 
 pub fn record_pat(path: ast::Path, pats: impl Iterator<Item = ast::Pat>) -> ast::RecordPat {
     let pats_str = pats.map(|p| p.syntax().to_string()).join(", ");
-    return from_text(&format!("{}{{ {} }}", path.syntax(), pats_str));
+    return from_text(&format!("{} {{ {} }}", path.syntax(), pats_str));
 
     fn from_text(text: &str) -> ast::RecordPat {
         ast_from_text(&format!("fn f({}: ())", text))
@@ -129,11 +129,11 @@ pub fn where_clause(preds: impl Iterator<Item = ast::WherePred>) -> ast::WhereCl
 }
 
 pub fn if_expression(condition: &ast::Expr, statement: &str) -> ast::IfExpr {
-    return ast_from_text(&format!(
+    ast_from_text(&format!(
         "fn f() {{ if !{} {{\n    {}\n}}\n}}",
         condition.syntax().text(),
         statement
-    ));
+    ))
 }
 
 fn ast_from_text<N: AstNode>(text: &str) -> N {
diff --git a/crates/ra_syntax/src/ast/traits.rs b/crates/ra_syntax/src/ast/traits.rs
index f275a4955..c2b005886 100644
--- a/crates/ra_syntax/src/ast/traits.rs
+++ b/crates/ra_syntax/src/ast/traits.rs
@@ -6,6 +6,7 @@ use itertools::Itertools;
 
 use crate::{
     ast::{self, child_opt, children, AstChildren, AstNode, AstToken},
+    match_ast,
     syntax_node::{SyntaxElementChildren, SyntaxNodeChildren},
 };
 
@@ -68,11 +69,12 @@ impl Iterator for ItemOrMacroIter {
     fn next(&mut self) -> Option<ItemOrMacro> {
         loop {
             let n = self.0.next()?;
-            if let Some(item) = ast::ModuleItem::cast(n.clone()) {
-                return Some(ItemOrMacro::Item(item));
-            }
-            if let Some(call) = ast::MacroCall::cast(n) {
-                return Some(ItemOrMacro::Macro(call));
+            match_ast! {
+                match n {
+                    ast::ModuleItem(it) => { return Some(ItemOrMacro::Item(it)) },
+                    ast::MacroCall(it) => { return Some(ItemOrMacro::Macro(it)) },
+                    _ => {},
+                }
             }
         }
     }
@@ -120,7 +122,7 @@ pub trait DocCommentsOwner: AstNode {
                 has_comments = true;
                 let prefix_len = comment.prefix().len();
 
-                let line = comment.text().as_str();
+                let line: &str = comment.text().as_str();
 
                 // Determine if the prefix or prefix + 1 char is stripped
                 let pos =
@@ -136,7 +138,10 @@ pub trait DocCommentsOwner: AstNode {
                     line.len()
                 };
 
-                line[pos..end].trim_end().to_owned()
+                // Note that we do not trim the end of the line here
+                // since whitespace can have special meaning at the end
+                // of a line in markdown.
+                line[pos..end].to_owned()
             })
             .join("\n");
 
diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs
index c315ba552..5dcb6a95a 100644
--- a/crates/ra_syntax/src/lib.rs
+++ b/crates/ra_syntax/src/lib.rs
@@ -160,6 +160,20 @@ impl SourceFile {
     }
 }
 
+/// Matches a `SyntaxNode` against an `ast` type.
+///
+/// # Example:
+///
+/// ```ignore
+/// match_ast! {
+///     match node {
+///         ast::CallExpr(it) => { ... },
+///         ast::MethodCallExpr(it) => { ... },
+///         ast::MacroCall(it) => { ... },
+///         _ => None,
+///     }
+/// }
+/// ```
 #[macro_export]
 macro_rules! match_ast {
     (match $node:ident {
diff --git a/crates/ra_syntax/test_data/parser/err/0024_many_type_parens.txt b/crates/ra_syntax/test_data/parser/err/0024_many_type_parens.txt
index 198daf7b4..0a93e11a5 100644
--- a/crates/ra_syntax/test_data/parser/err/0024_many_type_parens.txt
+++ b/crates/ra_syntax/test_data/parser/err/0024_many_type_parens.txt
@@ -179,50 +179,47 @@ SOURCE_FILE@[0; 240)
           ERROR@[148; 149)
             PLUS@[148; 149) "+"
         WHITESPACE@[149; 150) " "
-        EXPR_STMT@[150; 151)
-          PAREN_EXPR@[150; 151)
+        EXPR_STMT@[150; 180)
+          TUPLE_EXPR@[150; 180)
             L_PAREN@[150; 151) "("
-        EXPR_STMT@[151; 157)
-          FOR_EXPR@[151; 157)
-            FOR_KW@[151; 154) "for"
-            ERROR@[154; 155)
-              L_ANGLE@[154; 155) "<"
-            ERROR@[155; 157)
-              LIFETIME@[155; 157) "\'a"
-        EXPR_STMT@[157; 158)
-          ERROR@[157; 158)
-            R_ANGLE@[157; 158) ">"
-        WHITESPACE@[158; 159) " "
-        EXPR_STMT@[159; 180)
-          BIN_EXPR@[159; 180)
-            BIN_EXPR@[159; 178)
-              BIN_EXPR@[159; 169)
-                BIN_EXPR@[159; 167)
-                  PATH_EXPR@[159; 164)
-                    PATH@[159; 164)
-                      PATH_SEGMENT@[159; 164)
-                        NAME_REF@[159; 164)
-                          IDENT@[159; 164) "Trait"
-                  L_ANGLE@[164; 165) "<"
-                  ERROR@[165; 167)
-                    LIFETIME@[165; 167) "\'a"
-                R_ANGLE@[167; 168) ">"
-                ERROR@[168; 169)
-                  R_PAREN@[168; 169) ")"
-              WHITESPACE@[169; 170) " "
-              PLUS@[170; 171) "+"
-              WHITESPACE@[171; 172) " "
-              PAREN_EXPR@[172; 178)
-                L_PAREN@[172; 173) "("
-                PATH_EXPR@[173; 177)
-                  PATH@[173; 177)
-                    PATH_SEGMENT@[173; 177)
-                      NAME_REF@[173; 177)
-                        IDENT@[173; 177) "Copy"
-                R_PAREN@[177; 178) ")"
-            R_ANGLE@[178; 179) ">"
-            ERROR@[179; 180)
-              SEMI@[179; 180) ";"
+            BIN_EXPR@[151; 180)
+              BIN_EXPR@[151; 178)
+                BIN_EXPR@[151; 169)
+                  BIN_EXPR@[151; 167)
+                    BIN_EXPR@[151; 164)
+                      FOR_EXPR@[151; 157)
+                        FOR_KW@[151; 154) "for"
+                        ERROR@[154; 155)
+                          L_ANGLE@[154; 155) "<"
+                        ERROR@[155; 157)
+                          LIFETIME@[155; 157) "\'a"
+                      R_ANGLE@[157; 158) ">"
+                      WHITESPACE@[158; 159) " "
+                      PATH_EXPR@[159; 164)
+                        PATH@[159; 164)
+                          PATH_SEGMENT@[159; 164)
+                            NAME_REF@[159; 164)
+                              IDENT@[159; 164) "Trait"
+                    L_ANGLE@[164; 165) "<"
+                    ERROR@[165; 167)
+                      LIFETIME@[165; 167) "\'a"
+                  R_ANGLE@[167; 168) ">"
+                  ERROR@[168; 169)
+                    R_PAREN@[168; 169) ")"
+                WHITESPACE@[169; 170) " "
+                PLUS@[170; 171) "+"
+                WHITESPACE@[171; 172) " "
+                PAREN_EXPR@[172; 178)
+                  L_PAREN@[172; 173) "("
+                  PATH_EXPR@[173; 177)
+                    PATH@[173; 177)
+                      PATH_SEGMENT@[173; 177)
+                        NAME_REF@[173; 177)
+                          IDENT@[173; 177) "Copy"
+                  R_PAREN@[177; 178) ")"
+              R_ANGLE@[178; 179) ">"
+              ERROR@[179; 180)
+                SEMI@[179; 180) ";"
         WHITESPACE@[180; 185) "\n    "
         LET_STMT@[185; 235)
           LET_KW@[185; 188) "let"
@@ -307,18 +304,16 @@ error 146: expected expression
 error 147: expected SEMI
 error 148: expected expression
 error 149: expected SEMI
-error 151: expected expression
-error 151: expected R_PAREN
-error 151: expected SEMI
 error 154: expected pattern
 error 155: expected IN_KW
 error 155: expected expression
 error 157: expected a block
-error 157: expected expression
-error 158: expected SEMI
 error 165: expected expression
 error 168: expected expression
 error 179: expected expression
+error 180: expected COMMA
+error 180: expected expression
+error 180: expected R_PAREN
 error 180: expected SEMI
 error 215: expected COMMA
 error 215: expected R_ANGLE
diff --git a/crates/ra_syntax/test_data/parser/ok/0059_loops_in_parens.rs b/crates/ra_syntax/test_data/parser/ok/0059_loops_in_parens.rs
new file mode 100644
index 000000000..6e8b718aa
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/ok/0059_loops_in_parens.rs
@@ -0,0 +1,5 @@
+fn main() {
+    Some(for _ in [1].into_iter() {});
+    Some(loop { break; });
+    Some(while true {});
+}
diff --git a/crates/ra_syntax/test_data/parser/ok/0059_loops_in_parens.txt b/crates/ra_syntax/test_data/parser/ok/0059_loops_in_parens.txt
new file mode 100644
index 000000000..c011187ea
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/ok/0059_loops_in_parens.txt
@@ -0,0 +1,101 @@
+SOURCE_FILE@[0; 105)
+  FN_DEF@[0; 104)
+    FN_KW@[0; 2) "fn"
+    WHITESPACE@[2; 3) " "
+    NAME@[3; 7)
+      IDENT@[3; 7) "main"
+    PARAM_LIST@[7; 9)
+      L_PAREN@[7; 8) "("
+      R_PAREN@[8; 9) ")"
+    WHITESPACE@[9; 10) " "
+    BLOCK_EXPR@[10; 104)
+      BLOCK@[10; 104)
+        L_CURLY@[10; 11) "{"
+        WHITESPACE@[11; 16) "\n    "
+        EXPR_STMT@[16; 50)
+          CALL_EXPR@[16; 49)
+            PATH_EXPR@[16; 20)
+              PATH@[16; 20)
+                PATH_SEGMENT@[16; 20)
+                  NAME_REF@[16; 20)
+                    IDENT@[16; 20) "Some"
+            ARG_LIST@[20; 49)
+              L_PAREN@[20; 21) "("
+              FOR_EXPR@[21; 48)
+                FOR_KW@[21; 24) "for"
+                WHITESPACE@[24; 25) " "
+                PLACEHOLDER_PAT@[25; 26)
+                  UNDERSCORE@[25; 26) "_"
+                WHITESPACE@[26; 27) " "
+                IN_KW@[27; 29) "in"
+                WHITESPACE@[29; 30) " "
+                METHOD_CALL_EXPR@[30; 45)
+                  ARRAY_EXPR@[30; 33)
+                    L_BRACK@[30; 31) "["
+                    LITERAL@[31; 32)
+                      INT_NUMBER@[31; 32) "1"
+                    R_BRACK@[32; 33) "]"
+                  DOT@[33; 34) "."
+                  NAME_REF@[34; 43)
+                    IDENT@[34; 43) "into_iter"
+                  ARG_LIST@[43; 45)
+                    L_PAREN@[43; 44) "("
+                    R_PAREN@[44; 45) ")"
+                WHITESPACE@[45; 46) " "
+                BLOCK_EXPR@[46; 48)
+                  BLOCK@[46; 48)
+                    L_CURLY@[46; 47) "{"
+                    R_CURLY@[47; 48) "}"
+              R_PAREN@[48; 49) ")"
+          SEMI@[49; 50) ";"
+        WHITESPACE@[50; 55) "\n    "
+        EXPR_STMT@[55; 77)
+          CALL_EXPR@[55; 76)
+            PATH_EXPR@[55; 59)
+              PATH@[55; 59)
+                PATH_SEGMENT@[55; 59)
+                  NAME_REF@[55; 59)
+                    IDENT@[55; 59) "Some"
+            ARG_LIST@[59; 76)
+              L_PAREN@[59; 60) "("
+              LOOP_EXPR@[60; 75)
+                LOOP_KW@[60; 64) "loop"
+                WHITESPACE@[64; 65) " "
+                BLOCK_EXPR@[65; 75)
+                  BLOCK@[65; 75)
+                    L_CURLY@[65; 66) "{"
+                    WHITESPACE@[66; 67) " "
+                    EXPR_STMT@[67; 73)
+                      BREAK_EXPR@[67; 72)
+                        BREAK_KW@[67; 72) "break"
+                      SEMI@[72; 73) ";"
+                    WHITESPACE@[73; 74) " "
+                    R_CURLY@[74; 75) "}"
+              R_PAREN@[75; 76) ")"
+          SEMI@[76; 77) ";"
+        WHITESPACE@[77; 82) "\n    "
+        EXPR_STMT@[82; 102)
+          CALL_EXPR@[82; 101)
+            PATH_EXPR@[82; 86)
+              PATH@[82; 86)
+                PATH_SEGMENT@[82; 86)
+                  NAME_REF@[82; 86)
+                    IDENT@[82; 86) "Some"
+            ARG_LIST@[86; 101)
+              L_PAREN@[86; 87) "("
+              WHILE_EXPR@[87; 100)
+                WHILE_KW@[87; 92) "while"
+                WHITESPACE@[92; 93) " "
+                CONDITION@[93; 97)
+                  LITERAL@[93; 97)
+                    TRUE_KW@[93; 97) "true"
+                WHITESPACE@[97; 98) " "
+                BLOCK_EXPR@[98; 100)
+                  BLOCK@[98; 100)
+                    L_CURLY@[98; 99) "{"
+                    R_CURLY@[99; 100) "}"
+              R_PAREN@[100; 101) ")"
+          SEMI@[101; 102) ";"
+        WHITESPACE@[102; 103) "\n"
+        R_CURLY@[103; 104) "}"
+  WHITESPACE@[104; 105) "\n"