5 files changed, 150 insertions, 40 deletions

diff --git a/crates/ra_ide/src/completion/complete_postfix.rs b/crates/ra_ide/src/completion/complete_postfix.rs
index 0ba382165..0a00054b2 100644
--- a/crates/ra_ide/src/completion/complete_postfix.rs
+++ b/crates/ra_ide/src/completion/complete_postfix.rs
@@ -1,6 +1,9 @@
 //! FIXME: write short doc here
 
-use ra_syntax::{ast::AstNode, TextRange, TextUnit};
+use ra_syntax::{
+    ast::{self, AstNode},
+    TextRange, TextUnit,
+};
 use ra_text_edit::TextEdit;
 
 use crate::{
@@ -21,13 +24,8 @@ pub(super) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
         None => return,
     };
 
-    let receiver_text = if ctx.dot_receiver_is_ambiguous_float_literal {
-        let text = dot_receiver.syntax().text();
-        let without_dot = ..text.len() - TextUnit::of_char('.');
-        text.slice(without_dot).to_string()
-    } else {
-        dot_receiver.syntax().text().to_string()
-    };
+    let receiver_text =
+        get_receiver_text(dot_receiver, ctx.dot_receiver_is_ambiguous_float_literal);
 
     let receiver_ty = match ctx.sema.type_of_expr(&dot_receiver) {
         Some(it) => it,
@@ -35,10 +33,17 @@ pub(super) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
     };
 
     if receiver_ty.is_bool() || receiver_ty.is_unknown() {
-        postfix_snippet(ctx, "if", "if expr {}", &format!("if {} {{$0}}", receiver_text))
-            .add_to(acc);
         postfix_snippet(
             ctx,
+            &dot_receiver,
+            "if",
+            "if expr {}",
+            &format!("if {} {{$0}}", receiver_text),
+        )
+        .add_to(acc);
+        postfix_snippet(
+            ctx,
+            &dot_receiver,
             "while",
             "while expr {}",
             &format!("while {} {{\n$0\n}}", receiver_text),
@@ -46,28 +51,70 @@ pub(super) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
         .add_to(acc);
     }
 
-    postfix_snippet(ctx, "not", "!expr", &format!("!{}", receiver_text)).add_to(acc);
+    // !&&&42 is a compiler error, ergo process it before considering the references
+    postfix_snippet(ctx, &dot_receiver, "not", "!expr", &format!("!{}", receiver_text)).add_to(acc);
 
-    postfix_snippet(ctx, "ref", "&expr", &format!("&{}", receiver_text)).add_to(acc);
-    postfix_snippet(ctx, "refm", "&mut expr", &format!("&mut {}", receiver_text)).add_to(acc);
+    postfix_snippet(ctx, &dot_receiver, "ref", "&expr", &format!("&{}", receiver_text)).add_to(acc);
+    postfix_snippet(ctx, &dot_receiver, "refm", "&mut expr", &format!("&mut {}", receiver_text))
+        .add_to(acc);
+
+    // The rest of the postfix completions create an expression that moves an argument,
+    // so it's better to consider references now to avoid breaking the compilation
+    let dot_receiver = include_references(dot_receiver);
+    let receiver_text =
+        get_receiver_text(&dot_receiver, ctx.dot_receiver_is_ambiguous_float_literal);
 
     postfix_snippet(
         ctx,
+        &dot_receiver,
         "match",
         "match expr {}",
         &format!("match {} {{\n    ${{1:_}} => {{$0\\}},\n}}", receiver_text),
     )
     .add_to(acc);
 
-    postfix_snippet(ctx, "dbg", "dbg!(expr)", &format!("dbg!({})", receiver_text)).add_to(acc);
+    postfix_snippet(
+        ctx,
+        &dot_receiver,
+        "box",
+        "Box::new(expr)",
+        &format!("Box::new({})", receiver_text),
+    )
+    .add_to(acc);
 
-    postfix_snippet(ctx, "box", "Box::new(expr)", &format!("Box::new({})", receiver_text))
+    postfix_snippet(ctx, &dot_receiver, "dbg", "dbg!(expr)", &format!("dbg!({})", receiver_text))
         .add_to(acc);
 }
 
-fn postfix_snippet(ctx: &CompletionContext, label: &str, detail: &str, snippet: &str) -> Builder {
+fn get_receiver_text(receiver: &ast::Expr, receiver_is_ambiguous_float_literal: bool) -> String {
+    if receiver_is_ambiguous_float_literal {
+        let text = receiver.syntax().text();
+        let without_dot = ..text.len() - TextUnit::of_char('.');
+        text.slice(without_dot).to_string()
+    } else {
+        receiver.to_string()
+    }
+}
+
+fn include_references(initial_element: &ast::Expr) -> ast::Expr {
+    let mut resulting_element = initial_element.clone();
+    while let Some(parent_ref_element) =
+        resulting_element.syntax().parent().and_then(ast::RefExpr::cast)
+    {
+        resulting_element = ast::Expr::from(parent_ref_element);
+    }
+    resulting_element
+}
+
+fn postfix_snippet(
+    ctx: &CompletionContext,
+    receiver: &ast::Expr,
+    label: &str,
+    detail: &str,
+    snippet: &str,
+) -> Builder {
     let edit = {
-        let receiver_syntax = ctx.dot_receiver.as_ref().expect("no receiver available").syntax();
+        let receiver_syntax = receiver.syntax();
         let receiver_range = ctx.sema.original_range(receiver_syntax).range;
         let delete_range = TextRange::from_to(receiver_range.start(), ctx.source_range().end());
         TextEdit::replace(delete_range, snippet.to_string())
@@ -340,4 +387,63 @@ mod tests {
         "###
         );
     }
+
+    #[test]
+    fn postfix_completion_for_references() {
+        assert_debug_snapshot!(
+            do_postfix_completion(
+                r#"
+                fn main() {
+                    &&&&42.<|>
+                }
+                "#,
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "box",
+                source_range: [56; 56),
+                delete: [49; 56),
+                insert: "Box::new(&&&&42)",
+                detail: "Box::new(expr)",
+            },
+            CompletionItem {
+                label: "dbg",
+                source_range: [56; 56),
+                delete: [49; 56),
+                insert: "dbg!(&&&&42)",
+                detail: "dbg!(expr)",
+            },
+            CompletionItem {
+                label: "match",
+                source_range: [56; 56),
+                delete: [49; 56),
+                insert: "match &&&&42 {\n    ${1:_} => {$0\\},\n}",
+                detail: "match expr {}",
+            },
+            CompletionItem {
+                label: "not",
+                source_range: [56; 56),
+                delete: [53; 56),
+                insert: "!42",
+                detail: "!expr",
+            },
+            CompletionItem {
+                label: "ref",
+                source_range: [56; 56),
+                delete: [53; 56),
+                insert: "&42",
+                detail: "&expr",
+            },
+            CompletionItem {
+                label: "refm",
+                source_range: [56; 56),
+                delete: [53; 56),
+                insert: "&mut 42",
+                detail: "&mut expr",
+            },
+        ]
+        "###
+        );
+    }
 }
diff --git a/editors/code/package.json b/editors/code/package.json
index eb5748515..1d113ebb6 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -73,10 +73,18 @@
                         "type": "string"
                     },
                     "args": {
-                        "type": "array"
+                        "type": "array",
+                        "items": {
+                            "type": "string"
+                        }
                     },
                     "env": {
-                        "type": "object"
+                        "type": "object",
+                        "patternProperties": {
+                            ".+": {
+                                "type": "string"
+                            }
+                        }
                     }
                 }
             }
diff --git a/editors/code/src/client.ts b/editors/code/src/client.ts
index 08d821dd0..82ca749f3 100644
--- a/editors/code/src/client.ts
+++ b/editors/code/src/client.ts
@@ -99,8 +99,10 @@ export async function createClient(config: Config, serverPath: string): Promise<
     // Note that while the CallHierarchyFeature is stable the LSP protocol is not.
     res.registerFeature(new CallHierarchyFeature(res));
 
-    if (config.highlightingSemanticTokens) {
-        res.registerFeature(new SemanticTokensFeature(res));
+    if (config.package.enableProposedApi) {
+        if (config.highlightingSemanticTokens) {
+            res.registerFeature(new SemanticTokensFeature(res));
+        }
     }
 
     return res;
diff --git a/editors/code/src/config.ts b/editors/code/src/config.ts
index be5296fcf..602538ea1 100644
--- a/editors/code/src/config.ts
+++ b/editors/code/src/config.ts
@@ -38,17 +38,11 @@ export class Config {
     ]
         .map(opt => `${this.rootSection}.${opt}`);
 
-    readonly packageJsonVersion: string = vscode
-        .extensions
-        .getExtension(this.extensionId)!
-        .packageJSON
-        .version;
-
-    readonly releaseTag: string | undefined = vscode
-        .extensions
-        .getExtension(this.extensionId)!
-        .packageJSON
-        .releaseTag ?? undefined;
+    readonly package: {
+        version: string;
+        releaseTag: string | undefined;
+        enableProposedApi: boolean | undefined;
+    } = vscode.extensions.getExtension(this.extensionId)!.packageJSON;
 
     private cfg!: vscode.WorkspaceConfiguration;
 
@@ -62,7 +56,7 @@ export class Config {
         const enableLogging = this.cfg.get("trace.extension") as boolean;
         log.setEnabled(enableLogging);
         log.debug(
-            "Extension version:", this.packageJsonVersion,
+            "Extension version:", this.package.version,
             "using configuration:", this.cfg
         );
     }
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index 5d2da9a76..7b7c19dfc 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -110,9 +110,9 @@ async function bootstrap(config: Config, state: PersistentState): Promise<string
 }
 
 async function bootstrapExtension(config: Config, state: PersistentState): Promise<void> {
-    if (config.releaseTag === undefined) return;
+    if (config.package.releaseTag === undefined) return;
     if (config.channel === "stable") {
-        if (config.releaseTag === NIGHTLY_TAG) {
+        if (config.package.releaseTag === NIGHTLY_TAG) {
             vscode.window.showWarningMessage(`You are running a nightly version of rust-analyzer extension.
 To switch to stable, uninstall the extension and re-install it from the marketplace`);
         }
@@ -185,7 +185,7 @@ async function getServer(config: Config, state: PersistentState): Promise<string
         }
         return explicitPath;
     };
-    if (config.releaseTag === undefined) return "rust-analyzer";
+    if (config.package.releaseTag === undefined) return "rust-analyzer";
 
     let binaryName: string | undefined = undefined;
     if (process.arch === "x64" || process.arch === "x32") {
@@ -211,21 +211,21 @@ async function getServer(config: Config, state: PersistentState): Promise<string
         await state.updateServerVersion(undefined);
     }
 
-    if (state.serverVersion === config.packageJsonVersion) return dest;
+    if (state.serverVersion === config.package.version) return dest;
 
     if (config.askBeforeDownload) {
         const userResponse = await vscode.window.showInformationMessage(
-            `Language server version ${config.packageJsonVersion} for rust-analyzer is not installed.`,
+            `Language server version ${config.package.version} for rust-analyzer is not installed.`,
             "Download now"
         );
         if (userResponse !== "Download now") return dest;
     }
 
-    const release = await fetchRelease(config.releaseTag);
+    const release = await fetchRelease(config.package.releaseTag);
     const artifact = release.assets.find(artifact => artifact.name === binaryName);
     assert(!!artifact, `Bad release: ${JSON.stringify(release)}`);
 
     await download(artifact.browser_download_url, dest, "Downloading rust-analyzer server", { mode: 0o755 });
-    await state.updateServerVersion(config.packageJsonVersion);
+    await state.updateServerVersion(config.package.version);
     return dest;
 }