Merge #8231

8231: Fold consecutive consts and statics r=matklad a=MozarellaMan

PR to implement #8114

![const_fold](https://user-images.githubusercontent.com/48062697/112835083-b584c600-9090-11eb-968a-a95f4e9c1f6c.gif)


Co-authored-by: Ayomide Bamidele <ayoeze@hotmail.com>

crates/ide/src/folding_ranges.rs

@@ -17,6 +17,8 @@ pub enum FoldKind {
     Block,
     ArgList,
     Region,
+    Consts,
+    Statics,
 }
 
 #[derive(Debug)]
@@ -30,6 +32,8 @@ pub(crate) fn folding_ranges(file: &SourceFile) -> Vec<Fold> {
     let mut visited_comments = FxHashSet::default();
     let mut visited_imports = FxHashSet::default();
     let mut visited_mods = FxHashSet::default();
+    let mut visited_consts = FxHashSet::default();
+    let mut visited_statics = FxHashSet::default();
     // regions can be nested, here is a LIFO buffer
     let mut regions_starts: Vec<TextSize> = vec![];
 
@@ -91,6 +95,19 @@ pub(crate) fn folding_ranges(file: &SourceFile) -> Vec<Fold> {
                         res.push(Fold { range, kind: FoldKind::Mods })
                     }
                 }
+
+                // Fold groups of consts
+                if node.kind() == CONST && !visited_consts.contains(&node) {
+                    if let Some(range) = contiguous_range_for_group(&node, &mut visited_consts) {
+                        res.push(Fold { range, kind: FoldKind::Consts })
+                    }
+                }
+                // Fold groups of consts
+                if node.kind() == STATIC && !visited_statics.contains(&node) {
+                    if let Some(range) = contiguous_range_for_group(&node, &mut visited_statics) {
+                        res.push(Fold { range, kind: FoldKind::Statics })
+                    }
+                }
             }
         }
     }
@@ -250,6 +267,8 @@ mod tests {
                 FoldKind::Block => "block",
                 FoldKind::ArgList => "arglist",
                 FoldKind::Region => "region",
+                FoldKind::Consts => "consts",
+                FoldKind::Statics => "statics",
             };
             assert_eq!(kind, &attr.unwrap());
         }
@@ -457,4 +476,24 @@ calling_function(x,y);
 "#,
         )
     }
+
+    #[test]
+    fn fold_consecutive_const() {
+        check(
+            r#"
+<fold consts>const FIRST_CONST: &str = "first";
+const SECOND_CONST: &str = "second";</fold>
+            "#,
+        )
+    }
+
+    #[test]
+    fn fold_consecutive_static() {
+        check(
+            r#"
+<fold statics>static FIRST_STATIC: &str = "first";
+static SECOND_STATIC: &str = "second";</fold>
+            "#,
+        )
+    }
 }

crates/rust-analyzer/src/to_proto.rs

@@ -492,7 +492,11 @@ pub(crate) fn folding_range(
         FoldKind::Comment => Some(lsp_types::FoldingRangeKind::Comment),
         FoldKind::Imports => Some(lsp_types::FoldingRangeKind::Imports),
         FoldKind::Region => Some(lsp_types::FoldingRangeKind::Region),
-        FoldKind::Mods | FoldKind::Block | FoldKind::ArgList => None,
+        FoldKind::Mods
+        | FoldKind::Block
+        | FoldKind::ArgList
+        | FoldKind::Consts
+        | FoldKind::Statics => None,
     };
 
     let range = range(line_index, fold.range);