9 files changed, 408 insertions, 34 deletions

diff --git a/crates/ra_ide/src/snapshots/highlight_doctest.html b/crates/ra_ide/src/snapshots/highlight_doctest.html
index 5228df267..13a5d1b12 100644
--- a/crates/ra_ide/src/snapshots/highlight_doctest.html
+++ b/crates/ra_ide/src/snapshots/highlight_doctest.html
@@ -73,9 +73,13 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="comment">///</span>
     <span class="comment">/// ```</span>
     <span class="comment">///</span>
-    <span class="comment">/// ```</span>
+    <span class="comment">/// ```rust,no_run</span>
     <span class="comment">/// </span><span class="keyword">let</span> <span class="variable declaration">foobar</span> = <span class="struct">Foo</span>::<span class="function">new</span>().<span class="function">bar</span>();
     <span class="comment">/// ```</span>
+    <span class="comment">///</span>
+    <span class="comment">/// ```sh</span>
+    <span class="comment">/// echo 1</span>
+    <span class="comment">/// ```</span>
     <span class="keyword">pub</span> <span class="keyword">fn</span> <span class="function declaration">foo</span>(&<span class="self_keyword">self</span>) -&gt; <span class="builtin_type">bool</span> {
         <span class="bool_literal">true</span>
     }
diff --git a/crates/ra_ide/src/syntax_highlighting/injection.rs b/crates/ra_ide/src/syntax_highlighting/injection.rs
index a02ffe59e..929a5cc5c 100644
--- a/crates/ra_ide/src/syntax_highlighting/injection.rs
+++ b/crates/ra_ide/src/syntax_highlighting/injection.rs
@@ -53,6 +53,10 @@ pub(super) fn highlight_injection(
 /// Mapping from extracted documentation code to original code
 type RangesMap = BTreeMap<TextSize, TextSize>;
 
+const RUSTDOC_FENCE: &'static str = "```";
+const RUSTDOC_FENCE_TOKENS: &[&'static str] =
+    &["", "rust", "should_panic", "ignore", "no_run", "compile_fail", "edition2015", "edition2018"];
+
 /// Extracts Rust code from documentation comments as well as a mapping from
 /// the extracted source code back to the original source ranges.
 /// Lastly, a vector of new comment highlight ranges (spanning only the
@@ -67,6 +71,7 @@ pub(super) fn extract_doc_comments(
     // Mapping from extracted documentation code to original code
     let mut range_mapping: RangesMap = BTreeMap::new();
     let mut line_start = TextSize::try_from(prefix.len()).unwrap();
+    let mut is_codeblock = false;
     let mut is_doctest = false;
     // Replace the original, line-spanning comment ranges by new, only comment-prefix
     // spanning comment ranges.
@@ -76,8 +81,13 @@ pub(super) fn extract_doc_comments(
         .filter_map(|el| el.into_token().and_then(ast::Comment::cast))
         .filter(|comment| comment.kind().doc.is_some())
         .filter(|comment| {
-            if comment.text().contains("```") {
-                is_doctest = !is_doctest;
+            if let Some(idx) = comment.text().find(RUSTDOC_FENCE) {
+                is_codeblock = !is_codeblock;
+                // Check whether code is rust by inspecting fence guards
+                let guards = &comment.text()[idx + RUSTDOC_FENCE.len()..];
+                let is_rust =
+                    guards.split(',').all(|sub| RUSTDOC_FENCE_TOKENS.contains(&sub.trim()));
+                is_doctest = is_codeblock && is_rust;
                 false
             } else {
                 is_doctest
diff --git a/crates/ra_ide/src/syntax_highlighting/tests.rs b/crates/ra_ide/src/syntax_highlighting/tests.rs
index 062b3ff4a..ebf5b50ac 100644
--- a/crates/ra_ide/src/syntax_highlighting/tests.rs
+++ b/crates/ra_ide/src/syntax_highlighting/tests.rs
@@ -329,9 +329,13 @@ impl Foo {
     ///
     /// ```
     ///
-    /// ```
+    /// ```rust,no_run
     /// let foobar = Foo::new().bar();
     /// ```
+    ///
+    /// ```sh
+    /// echo 1
+    /// ```
     pub fn foo(&self) -> bool {
         true
     }
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index 0e7a937a0..0df7427cb 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -9,6 +9,7 @@
 
 use std::{ffi::OsString, path::PathBuf};
 
+use crate::diagnostics::DiagnosticsConfig;
 use lsp_types::ClientCapabilities;
 use ra_flycheck::FlycheckConfig;
 use ra_ide::{AssistConfig, CompletionConfig, HoverConfig, InlayHintsConfig};
@@ -20,6 +21,7 @@ pub struct Config {
     pub client_caps: ClientCapsConfig,
 
     pub publish_diagnostics: bool,
+    pub diagnostics: DiagnosticsConfig,
     pub lru_capacity: Option<usize>,
     pub proc_macro_srv: Option<(PathBuf, Vec<OsString>)>,
     pub files: FilesConfig,
@@ -136,6 +138,7 @@ impl Default for Config {
 
             with_sysroot: true,
             publish_diagnostics: true,
+            diagnostics: DiagnosticsConfig::default(),
             lru_capacity: None,
             proc_macro_srv: None,
             files: FilesConfig { watcher: FilesWatcher::Notify, exclude: Vec::new() },
@@ -184,6 +187,8 @@ impl Config {
 
         set(value, "/withSysroot", &mut self.with_sysroot);
         set(value, "/diagnostics/enable", &mut self.publish_diagnostics);
+        set(value, "/diagnostics/warningsAsInfo", &mut self.diagnostics.warnings_as_info);
+        set(value, "/diagnostics/warningsAsHint", &mut self.diagnostics.warnings_as_hint);
         set(value, "/lruCapacity", &mut self.lru_capacity);
         self.files.watcher = match get(value, "/files/watcher") {
             Some("client") => FilesWatcher::Client,
diff --git a/crates/rust-analyzer/src/diagnostics.rs b/crates/rust-analyzer/src/diagnostics.rs
index 25856c543..290609e7f 100644
--- a/crates/rust-analyzer/src/diagnostics.rs
+++ b/crates/rust-analyzer/src/diagnostics.rs
@@ -11,6 +11,12 @@ use crate::lsp_ext;
 pub type CheckFixes = Arc<HashMap<FileId, Vec<Fix>>>;
 
 #[derive(Debug, Default, Clone)]
+pub struct DiagnosticsConfig {
+    pub warnings_as_info: Vec<String>,
+    pub warnings_as_hint: Vec<String>,
+}
+
+#[derive(Debug, Default, Clone)]
 pub struct DiagnosticCollection {
     pub native: HashMap<FileId, Vec<Diagnostic>>,
     pub check: HashMap<FileId, Vec<Diagnostic>>,
diff --git a/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable_as_hint.snap b/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable_as_hint.snap
new file mode 100644
index 000000000..f0273315e
--- /dev/null
+++ b/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable_as_hint.snap
@@ -0,0 +1,86 @@
+---
+source: crates/rust-analyzer/src/diagnostics/to_proto.rs
+expression: diag
+---
+[
+    MappedRustDiagnostic {
+        location: Location {
+            uri: "file:///test/driver/subcommand/repl.rs",
+            range: Range {
+                start: Position {
+                    line: 290,
+                    character: 8,
+                },
+                end: Position {
+                    line: 290,
+                    character: 11,
+                },
+            },
+        },
+        diagnostic: Diagnostic {
+            range: Range {
+                start: Position {
+                    line: 290,
+                    character: 8,
+                },
+                end: Position {
+                    line: 290,
+                    character: 11,
+                },
+            },
+            severity: Some(
+                Hint,
+            ),
+            code: Some(
+                String(
+                    "unused_variables",
+                ),
+            ),
+            source: Some(
+                "rustc",
+            ),
+            message: "unused variable: `foo`\n#[warn(unused_variables)] on by default",
+            related_information: None,
+            tags: Some(
+                [
+                    Unnecessary,
+                ],
+            ),
+        },
+        fixes: [
+            CodeAction {
+                title: "consider prefixing with an underscore",
+                id: None,
+                group: None,
+                kind: Some(
+                    "quickfix",
+                ),
+                command: None,
+                edit: Some(
+                    SnippetWorkspaceEdit {
+                        changes: Some(
+                            {
+                                "file:///test/driver/subcommand/repl.rs": [
+                                    TextEdit {
+                                        range: Range {
+                                            start: Position {
+                                                line: 290,
+                                                character: 8,
+                                            },
+                                            end: Position {
+                                                line: 290,
+                                                character: 11,
+                                            },
+                                        },
+                                        new_text: "_foo",
+                                    },
+                                ],
+                            },
+                        ),
+                        document_changes: None,
+                    },
+                ),
+            },
+        ],
+    },
+]
diff --git a/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable_as_info.snap b/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable_as_info.snap
new file mode 100644
index 000000000..85fd050fd
--- /dev/null
+++ b/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable_as_info.snap
@@ -0,0 +1,86 @@
+---
+source: crates/rust-analyzer/src/diagnostics/to_proto.rs
+expression: diag
+---
+[
+    MappedRustDiagnostic {
+        location: Location {
+            uri: "file:///test/driver/subcommand/repl.rs",
+            range: Range {
+                start: Position {
+                    line: 290,
+                    character: 8,
+                },
+                end: Position {
+                    line: 290,
+                    character: 11,
+                },
+            },
+        },
+        diagnostic: Diagnostic {
+            range: Range {
+                start: Position {
+                    line: 290,
+                    character: 8,
+                },
+                end: Position {
+                    line: 290,
+                    character: 11,
+                },
+            },
+            severity: Some(
+                Information,
+            ),
+            code: Some(
+                String(
+                    "unused_variables",
+                ),
+            ),
+            source: Some(
+                "rustc",
+            ),
+            message: "unused variable: `foo`\n#[warn(unused_variables)] on by default",
+            related_information: None,
+            tags: Some(
+                [
+                    Unnecessary,
+                ],
+            ),
+        },
+        fixes: [
+            CodeAction {
+                title: "consider prefixing with an underscore",
+                id: None,
+                group: None,
+                kind: Some(
+                    "quickfix",
+                ),
+                command: None,
+                edit: Some(
+                    SnippetWorkspaceEdit {
+                        changes: Some(
+                            {
+                                "file:///test/driver/subcommand/repl.rs": [
+                                    TextEdit {
+                                        range: Range {
+                                            start: Position {
+                                                line: 290,
+                                                character: 8,
+                                            },
+                                            end: Position {
+                                                line: 290,
+                                                character: 11,
+                                            },
+                                        },
+                                        new_text: "_foo",
+                                    },
+                                ],
+                            },
+                        ),
+                        document_changes: None,
+                    },
+                ),
+            },
+        ],
+    },
+]
diff --git a/crates/rust-analyzer/src/diagnostics/to_proto.rs b/crates/rust-analyzer/src/diagnostics/to_proto.rs
index 24ff9b280..ba74f15f3 100644
--- a/crates/rust-analyzer/src/diagnostics/to_proto.rs
+++ b/crates/rust-analyzer/src/diagnostics/to_proto.rs
@@ -9,14 +9,24 @@ use lsp_types::{
 use ra_flycheck::{Applicability, DiagnosticLevel, DiagnosticSpan, DiagnosticSpanMacroExpansion};
 use stdx::format_to;
 
+use super::DiagnosticsConfig;
 use crate::{lsp_ext, to_proto::url_from_abs_path};
 
-/// Converts a Rust level string to a LSP severity
-fn map_level_to_severity(val: DiagnosticLevel) -> Option<DiagnosticSeverity> {
-    let res = match val {
+/// Determines the LSP severity from a diagnostic
+fn map_diagnostic_to_severity(
+    config: &DiagnosticsConfig,
+    val: &ra_flycheck::Diagnostic,
+) -> Option<DiagnosticSeverity> {
+    let res = match val.level {
         DiagnosticLevel::Ice => DiagnosticSeverity::Error,
         DiagnosticLevel::Error => DiagnosticSeverity::Error,
-        DiagnosticLevel::Warning => DiagnosticSeverity::Warning,
+        DiagnosticLevel::Warning => match &val.code {
+            Some(code) if config.warnings_as_hint.contains(&code.code) => DiagnosticSeverity::Hint,
+            Some(code) if config.warnings_as_info.contains(&code.code) => {
+                DiagnosticSeverity::Information
+            }
+            _ => DiagnosticSeverity::Warning,
+        },
         DiagnosticLevel::Note => DiagnosticSeverity::Information,
         DiagnosticLevel::Help => DiagnosticSeverity::Hint,
         DiagnosticLevel::Unknown => return None,
@@ -172,6 +182,7 @@ pub(crate) struct MappedRustDiagnostic {
 ///
 /// If the diagnostic has no primary span this will return `None`
 pub(crate) fn map_rust_diagnostic_to_lsp(
+    config: &DiagnosticsConfig,
     rd: &ra_flycheck::Diagnostic,
     workspace_root: &Path,
 ) -> Vec<MappedRustDiagnostic> {
@@ -180,7 +191,7 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
         return Vec::new();
     }
 
-    let severity = map_level_to_severity(rd.level);
+    let severity = map_diagnostic_to_severity(config, rd);
 
     let mut source = String::from("rustc");
     let mut code = rd.code.as_ref().map(|c| c.code.clone());
@@ -328,7 +339,7 @@ mod tests {
         );
 
         let workspace_root = Path::new("/test/");
-        let diag = map_rust_diagnostic_to_lsp(&diag, workspace_root);
+        let diag = map_rust_diagnostic_to_lsp(&DiagnosticsConfig::default(), &diag, workspace_root);
         insta::assert_debug_snapshot!(diag);
     }
 
@@ -410,7 +421,183 @@ mod tests {
         );
 
         let workspace_root = Path::new("/test/");
-        let diag = map_rust_diagnostic_to_lsp(&diag, workspace_root);
+        let diag = map_rust_diagnostic_to_lsp(&DiagnosticsConfig::default(), &diag, workspace_root);
+        insta::assert_debug_snapshot!(diag);
+    }
+
+    #[test]
+    #[cfg(not(windows))]
+    fn snap_rustc_unused_variable_as_info() {
+        let diag = parse_diagnostic(
+            r##"{
+    "message": "unused variable: `foo`",
+    "code": {
+        "code": "unused_variables",
+        "explanation": null
+    },
+    "level": "warning",
+    "spans": [
+        {
+            "file_name": "driver/subcommand/repl.rs",
+            "byte_start": 9228,
+            "byte_end": 9231,
+            "line_start": 291,
+            "line_end": 291,
+            "column_start": 9,
+            "column_end": 12,
+            "is_primary": true,
+            "text": [
+                {
+                    "text": "    let foo = 42;",
+                    "highlight_start": 9,
+                    "highlight_end": 12
+                }
+            ],
+            "label": null,
+            "suggested_replacement": null,
+            "suggestion_applicability": null,
+            "expansion": null
+        }
+    ],
+    "children": [
+        {
+            "message": "#[warn(unused_variables)] on by default",
+            "code": null,
+            "level": "note",
+            "spans": [],
+            "children": [],
+            "rendered": null
+        },
+        {
+            "message": "consider prefixing with an underscore",
+            "code": null,
+            "level": "help",
+            "spans": [
+                {
+                    "file_name": "driver/subcommand/repl.rs",
+                    "byte_start": 9228,
+                    "byte_end": 9231,
+                    "line_start": 291,
+                    "line_end": 291,
+                    "column_start": 9,
+                    "column_end": 12,
+                    "is_primary": true,
+                    "text": [
+                        {
+                            "text": "    let foo = 42;",
+                            "highlight_start": 9,
+                            "highlight_end": 12
+                        }
+                    ],
+                    "label": null,
+                    "suggested_replacement": "_foo",
+                    "suggestion_applicability": "MachineApplicable",
+                    "expansion": null
+                }
+            ],
+            "children": [],
+            "rendered": null
+        }
+    ],
+    "rendered": "warning: unused variable: `foo`\n   --> driver/subcommand/repl.rs:291:9\n    |\n291 |     let foo = 42;\n    |         ^^^ help: consider prefixing with an underscore: `_foo`\n    |\n    = note: #[warn(unused_variables)] on by default\n\n"
+    }"##,
+        );
+
+        let config = DiagnosticsConfig {
+            warnings_as_info: vec!["unused_variables".to_string()],
+            ..DiagnosticsConfig::default()
+        };
+
+        let workspace_root = Path::new("/test/");
+        let diag = map_rust_diagnostic_to_lsp(&config, &diag, workspace_root);
+        insta::assert_debug_snapshot!(diag);
+    }
+
+    #[test]
+    #[cfg(not(windows))]
+    fn snap_rustc_unused_variable_as_hint() {
+        let diag = parse_diagnostic(
+            r##"{
+    "message": "unused variable: `foo`",
+    "code": {
+        "code": "unused_variables",
+        "explanation": null
+    },
+    "level": "warning",
+    "spans": [
+        {
+            "file_name": "driver/subcommand/repl.rs",
+            "byte_start": 9228,
+            "byte_end": 9231,
+            "line_start": 291,
+            "line_end": 291,
+            "column_start": 9,
+            "column_end": 12,
+            "is_primary": true,
+            "text": [
+                {
+                    "text": "    let foo = 42;",
+                    "highlight_start": 9,
+                    "highlight_end": 12
+                }
+            ],
+            "label": null,
+            "suggested_replacement": null,
+            "suggestion_applicability": null,
+            "expansion": null
+        }
+    ],
+    "children": [
+        {
+            "message": "#[warn(unused_variables)] on by default",
+            "code": null,
+            "level": "note",
+            "spans": [],
+            "children": [],
+            "rendered": null
+        },
+        {
+            "message": "consider prefixing with an underscore",
+            "code": null,
+            "level": "help",
+            "spans": [
+                {
+                    "file_name": "driver/subcommand/repl.rs",
+                    "byte_start": 9228,
+                    "byte_end": 9231,
+                    "line_start": 291,
+                    "line_end": 291,
+                    "column_start": 9,
+                    "column_end": 12,
+                    "is_primary": true,
+                    "text": [
+                        {
+                            "text": "    let foo = 42;",
+                            "highlight_start": 9,
+                            "highlight_end": 12
+                        }
+                    ],
+                    "label": null,
+                    "suggested_replacement": "_foo",
+                    "suggestion_applicability": "MachineApplicable",
+                    "expansion": null
+                }
+            ],
+            "children": [],
+            "rendered": null
+        }
+    ],
+    "rendered": "warning: unused variable: `foo`\n   --> driver/subcommand/repl.rs:291:9\n    |\n291 |     let foo = 42;\n    |         ^^^ help: consider prefixing with an underscore: `_foo`\n    |\n    = note: #[warn(unused_variables)] on by default\n\n"
+    }"##,
+        );
+
+        let config = DiagnosticsConfig {
+            warnings_as_hint: vec!["unused_variables".to_string()],
+            ..DiagnosticsConfig::default()
+        };
+
+        let workspace_root = Path::new("/test/");
+        let diag = map_rust_diagnostic_to_lsp(&config, &diag, workspace_root);
         insta::assert_debug_snapshot!(diag);
     }
 
@@ -534,7 +721,7 @@ mod tests {
         );
 
         let workspace_root = Path::new("/test/");
-        let diag = map_rust_diagnostic_to_lsp(&diag, workspace_root);
+        let diag = map_rust_diagnostic_to_lsp(&DiagnosticsConfig::default(), &diag, workspace_root);
         insta::assert_debug_snapshot!(diag);
     }
 
@@ -654,7 +841,7 @@ mod tests {
         );
 
         let workspace_root = Path::new("/test/");
-        let diag = map_rust_diagnostic_to_lsp(&diag, workspace_root);
+        let diag = map_rust_diagnostic_to_lsp(&DiagnosticsConfig::default(), &diag, workspace_root);
         insta::assert_debug_snapshot!(diag);
     }
 
@@ -697,7 +884,7 @@ mod tests {
         );
 
         let workspace_root = Path::new("/test/");
-        let diag = map_rust_diagnostic_to_lsp(&diag, workspace_root);
+        let diag = map_rust_diagnostic_to_lsp(&DiagnosticsConfig::default(), &diag, workspace_root);
         insta::assert_debug_snapshot!(diag);
     }
 
@@ -968,7 +1155,7 @@ mod tests {
         );
 
         let workspace_root = Path::new("/test/");
-        let diag = map_rust_diagnostic_to_lsp(&diag, workspace_root);
+        let diag = map_rust_diagnostic_to_lsp(&DiagnosticsConfig::default(), &diag, workspace_root);
         insta::assert_debug_snapshot!(diag);
     }
 
@@ -1197,7 +1384,7 @@ mod tests {
         );
 
         let workspace_root = Path::new("/test/");
-        let diag = map_rust_diagnostic_to_lsp(&diag, workspace_root);
+        let diag = map_rust_diagnostic_to_lsp(&DiagnosticsConfig::default(), &diag, workspace_root);
         insta::assert_debug_snapshot!(diag);
     }
 
@@ -1330,7 +1517,7 @@ mod tests {
         );
 
         let workspace_root = Path::new("/test/");
-        let diag = map_rust_diagnostic_to_lsp(&diag, workspace_root);
+        let diag = map_rust_diagnostic_to_lsp(&DiagnosticsConfig::default(), &diag, workspace_root);
         insta::assert_debug_snapshot!(diag);
     }
 }
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index cc9bb1726..80cfd3c28 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -669,14 +669,11 @@ fn apply_document_changes(
     mut line_index: Cow<'_, LineIndex>,
     content_changes: Vec<TextDocumentContentChangeEvent>,
 ) {
-    // Remove when https://github.com/rust-analyzer/rust-analyzer/issues/4263 is fixed.
-    let backup_text = old_text.clone();
-    let backup_changes = content_changes.clone();
-
     // The changes we got must be applied sequentially, but can cross lines so we
     // have to keep our line index updated.
     // Some clients (e.g. Code) sort the ranges in reverse. As an optimization, we
     // remember the last valid line in the index and only rebuild it if needed.
+    // The VFS will normalize the end of lines to `\n`.
     enum IndexValid {
         All,
         UpToLineExclusive(u64),
@@ -700,19 +697,7 @@ fn apply_document_changes(
                 }
                 index_valid = IndexValid::UpToLineExclusive(range.start.line);
                 let range = from_proto::text_range(&line_index, range);
-                let mut text = old_text.to_owned();
-                match std::panic::catch_unwind(move || {
-                    text.replace_range(Range::<usize>::from(range), &change.text);
-                    text
-                }) {
-                    Ok(t) => *old_text = t,
-                    Err(e) => {
-                        eprintln!("Bug in incremental text synchronization. Please report the following output on https://github.com/rust-analyzer/rust-analyzer/issues/4263");
-                        dbg!(&backup_text);
-                        dbg!(&backup_changes);
-                        std::panic::resume_unwind(e);
-                    }
-                }
+                old_text.replace_range(Range::<usize>::from(range), &change.text);
             }
             None => {
                 *old_text = change.text;
@@ -734,6 +719,7 @@ fn on_check_task(
 
         CheckTask::AddDiagnostic { workspace_root, diagnostic } => {
             let diagnostics = crate::diagnostics::to_proto::map_rust_diagnostic_to_lsp(
+                &global_state.config.diagnostics,
                 &diagnostic,
                 &workspace_root,
             );