highlight mutable variables differently

crates/ra_hir/src/lib.rs

@@ -68,6 +68,7 @@ pub use self::{
     source_binder::{PathResolution, ScopeEntryWithSyntax, SourceAnalyzer},
     source_id::{AstIdMap, ErasedFileAstId},
     ty::{display::HirDisplay, ApplicationTy, CallableDef, Substs, TraitRef, Ty, TypeCtor},
+    type_ref::Mutability,
 };
 
 pub use self::code_model::{

crates/ra_ide_api/src/snapshots/highlighting.html

@@ -12,6 +12,7 @@ pre        { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padding: 0.4e
 .attribute          { color: #BFEBBF; }
 .literal            { color: #DFAF8F; }
 .macro              { color: #DFAF8F; }
+.variable\.mut     { color: #DFAF8F; }
 
 .keyword            { color: #F0DFAF; }
 .keyword\.unsafe   { color: #F0DFAF; font-weight: bold; }
@@ -32,9 +33,15 @@ pre        { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padding: 0.4e
 <span class="keyword">fn</span> <span class="function">main</span>() {
     <span class="macro">println</span><span class="macro">!</span>(<span class="string">"Hello, {}!"</span>, <span class="literal">92</span>);
 
-    <span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable" data-binding-hash="9636295041291189729" style="color: hsl(51,57%,74%);">vec</span> = <span class="text">Vec</span>::<span class="text">new</span>();
+    <span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable.mut">vec</span> = <span class="text">Vec</span>::<span class="text">new</span>();
     <span class="keyword.control">if</span> <span class="keyword">true</span> {
-        <span class="variable" data-binding-hash="8496027264380925433" style="color: hsl(18,48%,55%);">vec</span>.<span class="text">push</span>(<span class="type">Foo</span> { <span class="field">x</span>: <span class="literal">0</span>, <span class="field">y</span>: <span class="literal">1</span> });
+        <span class="variable.mut">vec</span>.<span class="text">push</span>(<span class="type">Foo</span> { <span class="field">x</span>: <span class="literal">0</span>, <span class="field">y</span>: <span class="literal">1</span> });
     }
-    <span class="keyword.unsafe">unsafe</span> { <span class="variable" data-binding-hash="8496027264380925433" style="color: hsl(18,48%,55%);">vec</span>.<span class="text">set_len</span>(<span class="literal">0</span>); }
+    <span class="keyword.unsafe">unsafe</span> { <span class="variable.mut">vec</span>.<span class="text">set_len</span>(<span class="literal">0</span>); }
+
+    <span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable.mut">x</span> = <span class="literal">42</span>;
+    <span class="keyword">let</span> <span class="variable.mut">y</span> = &<span class="keyword">mut</span> <span class="variable.mut">x</span>;
+    <span class="keyword">let</span> <span class="variable">z</span> = &<span class="variable.mut">y</span>;
+
+    <span class="variable.mut">y</span>;
 }</code></pre>

crates/ra_ide_api/src/snapshots/rainbow_highlighting.html

@@ -12,6 +12,7 @@ pre        { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padding: 0.4e
 .attribute          { color: #BFEBBF; }
 .literal            { color: #DFAF8F; }
 .macro              { color: #DFAF8F; }
+.variable\.mut     { color: #DFAF8F; }
 
 .keyword            { color: #F0DFAF; }
 .keyword\.unsafe   { color: #F0DFAF; font-weight: bold; }

crates/ra_ide_api/src/syntax_highlighting.rs

@@ -1,9 +1,11 @@
 use rustc_hash::{FxHashMap, FxHashSet};
 
+use hir::{Mutability, Ty};
 use ra_db::SourceDatabase;
 use ra_prof::profile;
 use ra_syntax::{
-    ast, AstNode, Direction, SmolStr, SyntaxElement, SyntaxKind, SyntaxKind::*, TextRange, T,
+    ast, AstNode, Direction, Pat, PatKind, SmolStr, SyntaxElement, SyntaxKind, SyntaxKind::*,
+    TextRange, T,
 };
 
 use crate::{db::RootDatabase, FileId};
@@ -30,6 +32,27 @@ fn is_control_keyword(kind: SyntaxKind) -> bool {
     }
 }
 
+fn is_variable_mutable(db: &RootDatabase, analyzer: &hir::SourceAnalyzer, pat: &Pat) -> bool {
+    let ty = analyzer.type_of_pat(db, pat).unwrap_or(Ty::Unknown);
+    let is_ty_mut = {
+        if let Some((_, mutability)) = ty.as_reference() {
+            match mutability {
+                Mutability::Shared => false,
+                Mutability::Mut => true,
+            }
+        } else {
+            false
+        }
+    };
+
+    let is_pat_mut = match pat.kind() {
+        PatKind::BindPat(bind_pat) => bind_pat.is_mutable(),
+        _ => false,
+    };
+
+    is_ty_mut || is_pat_mut
+}
+
 pub(crate) fn highlight(db: &RootDatabase, file_id: FileId) -> Vec<HighlightedRange> {
     let _p = profile("highlight");
     let parse = db.parse(file_id);
@@ -97,8 +120,12 @@ pub(crate) fn highlight(db: &RootDatabase, file_id: FileId) -> Vec<HighlightedRa
                                 calc_binding_hash(file_id, &text, *shadow_count)
                             });
 
+                            if is_variable_mutable(db, &analyzer, ptr.to_node(root)) {
+                                "variable.mut"
+                            } else {
                                 "variable"
                             }
+                        }
                         Some(SelfParam(_)) => "type",
                         Some(GenericParam(_)) => "type",
                         None => "text",
@@ -109,7 +136,8 @@ pub(crate) fn highlight(db: &RootDatabase, file_id: FileId) -> Vec<HighlightedRa
             }
             NAME => {
                 if let Some(name) = node.as_node().and_then(ast::Name::cast) {
-                    if name.syntax().ancestors().any(|x| ast::BindPat::cast(x).is_some()) {
+                    let analyzer = hir::SourceAnalyzer::new(db, file_id, name.syntax(), None);
+                    if let Some(pat) = name.syntax().ancestors().find_map(Pat::cast) {
                         binding_hash = Some({
                             let text = name.syntax().text().to_smol_string();
                             let shadow_count =
@@ -117,7 +145,12 @@ pub(crate) fn highlight(db: &RootDatabase, file_id: FileId) -> Vec<HighlightedRa
                             *shadow_count += 1;
                             calc_binding_hash(file_id, &text, *shadow_count)
                         });
+
+                        if is_variable_mutable(db, &analyzer, pat) {
+                            "variable.mut"
+                        } else {
                             "variable"
+                        }
                     } else if name
                         .syntax()
                         .parent()
@@ -253,6 +286,7 @@ pre        { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padding: 0.4e
 .attribute          { color: #BFEBBF; }
 .literal            { color: #DFAF8F; }
 .macro              { color: #DFAF8F; }
+.variable\\.mut     { color: #DFAF8F; }
 
 .keyword            { color: #F0DFAF; }
 .keyword\\.unsafe   { color: #F0DFAF; font-weight: bold; }
@@ -289,12 +323,18 @@ fn main() {
         vec.push(Foo { x: 0, y: 1 });
     }
     unsafe { vec.set_len(0); }
+
+    let mut x = 42;
+    let y = &mut x;
+    let z = &y;
+
+    y;
 }
 "#
             .trim(),
         );
         let dst_file = project_dir().join("crates/ra_ide_api/src/snapshots/highlighting.html");
-        let actual_html = &analysis.highlight_as_html(file_id, true).unwrap();
+        let actual_html = &analysis.highlight_as_html(file_id, false).unwrap();
         let expected_html = &read_text(&dst_file);
         std::fs::write(dst_file, &actual_html).unwrap();
         assert_eq_text!(expected_html, actual_html);

crates/ra_syntax/src/lib.rs

@@ -38,7 +38,7 @@ use ra_text_edit::AtomTextEdit;
 use crate::syntax_node::GreenNode;
 
 pub use crate::{
-    ast::AstNode,
+    ast::{AstNode, Pat, PatKind},
     parsing::{classify_literal, tokenize, Token},
     ptr::{AstPtr, SyntaxNodePtr},
     syntax_error::{Location, SyntaxError, SyntaxErrorKind},

editors/code/package.json

@@ -432,6 +432,15 @@
                     "highContrast": "#4EC9B0"
                 }
             },
+            {
+                "id": "ralsp.variable.mut",
+                "description": "Color for mutable variables",
+                "defaults": {
+                    "dark": "#4e65c9",
+                    "light": "#263199",
+                    "highContrast": "#4e65c9"
+                }
+            },
             {
                 "id": "ralsp.module",
                 "description": "Color for modules",

editors/code/src/highlighting.ts

@@ -56,6 +56,7 @@ export class Highlighter {
             colorContrib('literal'),
             colorContrib('macro'),
             colorContrib('variable'),
+            colorContrib('variable.mut'),
             colorContrib('field'),
             colorContrib('module')
         ];