Merge #3564

3564: Better handling of a few kinds of cargo/clippy diagnostics r=matklad a=kiljacken

This was initially supposed to just be a fix for #3433, but I caught a few things that ended up being useful as well.

This PR primarily makes us handle multi-edit fix suggestions properly. Instead of just applying the first fix we apply all the parts of the fix in a single action.

Second up, this PR handles diagnostics with multiple primary spans, f.x. the unused import diagnostic from rustc:
![image](https://user-images.githubusercontent.com/209321/76531793-03269480-6476-11ea-9180-41c0ea705553.png)

The LSP doesn't handle this too well, as it only support a single complete range for each diagnostic, so we get duplicate messages in the problem panel of VSCode:
![image](https://user-images.githubusercontent.com/209321/76531901-29e4cb00-6476-11ea-9746-cd57f8974b85.png)

However, I feel like the improved visual aspect in-editor outweighs the duplication in the problem panel. I'm open to not including the second commit if anybody really doesn't like the idea of duplicate diagnostics in the problem pane.

Fixes #3433
Fixes #3257

Co-authored-by: Emil Lauridsen <mine809@gmail.com>

Author: bors[bot]

crates/ra_cargo_watch/src/conv.rs

@@ -8,6 +8,7 @@ use lsp_types::{
     Location, NumberOrString, Position, Range, TextEdit, Url, WorkspaceEdit,
 };
 use std::{
+    collections::HashMap,
     fmt::Write,
     path::{Component, Path, PathBuf, Prefix},
     str::FromStr,
@@ -126,44 +127,34 @@ fn map_rust_child_diagnostic(
     rd: &RustDiagnostic,
     workspace_root: &PathBuf,
 ) -> MappedRustChildDiagnostic {
-    let span: &DiagnosticSpan = match rd.spans.iter().find(|s| s.is_primary) {
-        Some(span) => span,
-        None => {
-            // `rustc` uses these spanless children as a way to print multi-line
-            // messages
-            return MappedRustChildDiagnostic::MessageLine(rd.message.clone());
+    let spans: Vec<&DiagnosticSpan> = rd.spans.iter().filter(|s| s.is_primary).collect();
+    if spans.is_empty() {
+        // `rustc` uses these spanless children as a way to print multi-line
+        // messages
+        return MappedRustChildDiagnostic::MessageLine(rd.message.clone());
+    }
+
+    let mut edit_map: HashMap<Url, Vec<TextEdit>> = HashMap::new();
+    for &span in &spans {
+        if let Some(suggested_replacement) = &span.suggested_replacement {
+            let location = map_span_to_location(span, workspace_root);
+            let edit = TextEdit::new(location.range, suggested_replacement.clone());
+            edit_map.entry(location.uri).or_default().push(edit);
         }
-    };
-
-    // If we have a primary span use its location, otherwise use the parent
-    let location = map_span_to_location(&span, workspace_root);
-
-    if let Some(suggested_replacement) = &span.suggested_replacement {
-        // Include our replacement in the title unless it's empty
-        let title = if !suggested_replacement.is_empty() {
-            format!("{}: '{}'", rd.message, suggested_replacement)
-        } else {
-            rd.message.clone()
-        };
-
-        let edit = {
-            let edits = vec![TextEdit::new(location.range, suggested_replacement.clone())];
-            let mut edit_map = std::collections::HashMap::new();
-            edit_map.insert(location.uri, edits);
-            WorkspaceEdit::new(edit_map)
-        };
+    }
 
+    if !edit_map.is_empty() {
         MappedRustChildDiagnostic::SuggestedFix(CodeAction {
-            title,
+            title: rd.message.clone(),
             kind: Some("quickfix".to_string()),
             diagnostics: None,
-            edit: Some(edit),
+            edit: Some(WorkspaceEdit::new(edit_map)),
             command: None,
             is_preferred: None,
         })
     } else {
         MappedRustChildDiagnostic::Related(DiagnosticRelatedInformation {
-            location,
+            location: map_span_to_location(spans[0], workspace_root),
             message: rd.message.clone(),
         })
     }
@@ -189,13 +180,13 @@ pub(crate) struct MappedRustDiagnostic {
 pub(crate) fn map_rust_diagnostic_to_lsp(
     rd: &RustDiagnostic,
     workspace_root: &PathBuf,
-) -> Option<MappedRustDiagnostic> {
-    let primary_span = rd.spans.iter().find(|s| s.is_primary)?;
-
-    let location = map_span_to_location(&primary_span, workspace_root);
+) -> Vec<MappedRustDiagnostic> {
+    let primary_spans: Vec<&DiagnosticSpan> = rd.spans.iter().filter(|s| s.is_primary).collect();
+    if primary_spans.is_empty() {
+        return vec![];
+    }
 
     let severity = map_level_to_severity(rd.level);
-    let mut primary_span_label = primary_span.label.as_ref();
 
     let mut source = String::from("rustc");
     let mut code = rd.code.as_ref().map(|c| c.code.clone());
@@ -208,19 +199,10 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
         }
     }
 
+    let mut needs_primary_span_label = true;
     let mut related_information = vec![];
     let mut tags = vec![];
 
-    // If error occurs from macro expansion, add related info pointing to
-    // where the error originated
-    if !is_from_macro(&primary_span.file_name) && primary_span.expansion.is_some() {
-        let def_loc = map_span_to_location_naive(&primary_span, workspace_root);
-        related_information.push(DiagnosticRelatedInformation {
-            location: def_loc,
-            message: "Error originated from macro here".to_string(),
-        });
-    }
-
     for secondary_span in rd.spans.iter().filter(|s| !s.is_primary) {
         let related = map_secondary_span_to_related(secondary_span, workspace_root);
         if let Some(related) = related {
@@ -240,15 +222,11 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
 
                 // These secondary messages usually duplicate the content of the
                 // primary span label.
-                primary_span_label = None;
+                needs_primary_span_label = false;
             }
         }
     }
 
-    if let Some(primary_span_label) = primary_span_label {
-        write!(&mut message, "\n{}", primary_span_label).unwrap();
-    }
-
     if is_unused_or_unnecessary(rd) {
         tags.push(DiagnosticTag::Unnecessary);
     }
@@ -257,21 +235,45 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
         tags.push(DiagnosticTag::Deprecated);
     }
 
-    let diagnostic = Diagnostic {
-        range: location.range,
-        severity,
-        code: code.map(NumberOrString::String),
-        source: Some(source),
-        message,
-        related_information: if !related_information.is_empty() {
-            Some(related_information)
-        } else {
-            None
-        },
-        tags: if !tags.is_empty() { Some(tags) } else { None },
-    };
-
-    Some(MappedRustDiagnostic { location, diagnostic, fixes })
+    primary_spans
+        .iter()
+        .map(|primary_span| {
+            let location = map_span_to_location(&primary_span, workspace_root);
+
+            let mut message = message.clone();
+            if needs_primary_span_label {
+                if let Some(primary_span_label) = &primary_span.label {
+                    write!(&mut message, "\n{}", primary_span_label).unwrap();
+                }
+            }
+
+            // If error occurs from macro expansion, add related info pointing to
+            // where the error originated
+            if !is_from_macro(&primary_span.file_name) && primary_span.expansion.is_some() {
+                let def_loc = map_span_to_location_naive(&primary_span, workspace_root);
+                related_information.push(DiagnosticRelatedInformation {
+                    location: def_loc,
+                    message: "Error originated from macro here".to_string(),
+                });
+            }
+
+            let diagnostic = Diagnostic {
+                range: location.range,
+                severity,
+                code: code.clone().map(NumberOrString::String),
+                source: Some(source.clone()),
+                message,
+                related_information: if !related_information.is_empty() {
+                    Some(related_information.clone())
+                } else {
+                    None
+                },
+                tags: if !tags.is_empty() { Some(tags.clone()) } else { None },
+            };
+
+            MappedRustDiagnostic { location, diagnostic, fixes: fixes.clone() }
+        })
+        .collect()
 }
 
 /// Returns a `Url` object from a given path, will lowercase drive letters if present.

crates/ra_cargo_watch/src/conv/snapshots/ra_cargo_watch__conv__test__snap_clippy_pass_by_ref.snap

@@ -2,98 +2,100 @@
 source: crates/ra_cargo_watch/src/conv/test.rs
 expression: diag
 ---
-MappedRustDiagnostic {
-    location: Location {
-        uri: "file:///test/compiler/mir/tagset.rs",
-        range: Range {
-            start: Position {
-                line: 41,
-                character: 23,
-            },
-            end: Position {
-                line: 41,
-                character: 28,
+[
+    MappedRustDiagnostic {
+        location: Location {
+            uri: "file:///test/compiler/mir/tagset.rs",
+            range: Range {
+                start: Position {
+                    line: 41,
+                    character: 23,
+                },
+                end: Position {
+                    line: 41,
+                    character: 28,
+                },
             },
         },
-    },
-    diagnostic: Diagnostic {
-        range: Range {
-            start: Position {
-                line: 41,
-                character: 23,
-            },
-            end: Position {
-                line: 41,
-                character: 28,
+        diagnostic: Diagnostic {
+            range: Range {
+                start: Position {
+                    line: 41,
+                    character: 23,
+                },
+                end: Position {
+                    line: 41,
+                    character: 28,
+                },
             },
-        },
-        severity: Some(
-            Warning,
-        ),
-        code: Some(
-            String(
-                "trivially_copy_pass_by_ref",
+            severity: Some(
+                Warning,
             ),
-        ),
-        source: Some(
-            "clippy",
-        ),
-        message: "this argument is passed by reference, but would be more efficient if passed by value\n#[warn(clippy::trivially_copy_pass_by_ref)] implied by #[warn(clippy::all)]\nfor further information visit https://rust-lang.github.io/rust-clippy/master/index.html#trivially_copy_pass_by_ref",
-        related_information: Some(
-            [
-                DiagnosticRelatedInformation {
-                    location: Location {
-                        uri: "file:///test/compiler/lib.rs",
-                        range: Range {
-                            start: Position {
-                                line: 0,
-                                character: 8,
-                            },
-                            end: Position {
-                                line: 0,
-                                character: 19,
+            code: Some(
+                String(
+                    "trivially_copy_pass_by_ref",
+                ),
+            ),
+            source: Some(
+                "clippy",
+            ),
+            message: "this argument is passed by reference, but would be more efficient if passed by value\n#[warn(clippy::trivially_copy_pass_by_ref)] implied by #[warn(clippy::all)]\nfor further information visit https://rust-lang.github.io/rust-clippy/master/index.html#trivially_copy_pass_by_ref",
+            related_information: Some(
+                [
+                    DiagnosticRelatedInformation {
+                        location: Location {
+                            uri: "file:///test/compiler/lib.rs",
+                            range: Range {
+                                start: Position {
+                                    line: 0,
+                                    character: 8,
+                                },
+                                end: Position {
+                                    line: 0,
+                                    character: 19,
+                                },
                             },
                         },
+                        message: "lint level defined here",
                     },
-                    message: "lint level defined here",
-                },
-            ],
-        ),
-        tags: None,
-    },
-    fixes: [
-        CodeAction {
-            title: "consider passing by value instead: \'self\'",
-            kind: Some(
-                "quickfix",
+                ],
             ),
-            diagnostics: None,
-            edit: Some(
-                WorkspaceEdit {
-                    changes: Some(
-                        {
-                            "file:///test/compiler/mir/tagset.rs": [
-                                TextEdit {
-                                    range: Range {
-                                        start: Position {
-                                            line: 41,
-                                            character: 23,
-                                        },
-                                        end: Position {
-                                            line: 41,
-                                            character: 28,
+            tags: None,
+        },
+        fixes: [
+            CodeAction {
+                title: "consider passing by value instead",
+                kind: Some(
+                    "quickfix",
+                ),
+                diagnostics: None,
+                edit: Some(
+                    WorkspaceEdit {
+                        changes: Some(
+                            {
+                                "file:///test/compiler/mir/tagset.rs": [
+                                    TextEdit {
+                                        range: Range {
+                                            start: Position {
+                                                line: 41,
+                                                character: 23,
+                                            },
+                                            end: Position {
+                                                line: 41,
+                                                character: 28,
+                                            },
                                         },
+                                        new_text: "self",
                                     },
-                                    new_text: "self",
-                                },
-                            ],
-                        },
-                    ),
-                    document_changes: None,
-                },
-            ),
-            command: None,
-            is_preferred: None,
-        },
-    ],
-}
+                                ],
+                            },
+                        ),
+                        document_changes: None,
+                    },
+                ),
+                command: None,
+                is_preferred: None,
+            },
+        ],
+    },
+]