Handle macro error diagnostics

Author: alexheretic

src/actions/diagnostics.rs

@@ -136,7 +136,13 @@ pub fn parse_diagnostics(
             "rustc"
         };
 
-        let rls_span = span.rls_span().zero_indexed();
+        let rls_span = if span.file_name.ends_with(" macros>") && span.expansion.is_some() {
+            // span points to a macro, use a more useful source location
+            &span.expansion.as_ref().unwrap().span
+        } else {
+            span
+        }.rls_span().zero_indexed();
+
         let file_path = cwd.join(&rls_span.file);
 
         let diagnostic = Diagnostic {
@@ -335,6 +341,7 @@ impl IsWithin for Range {
 #[cfg(test)]
 mod diagnostic_message_test {
     use super::*;
+    use ls_types::Position;
 
     pub(super) fn parse_compiler_message(
         compiler_message: &str,
@@ -649,14 +656,49 @@ help: consider borrowing here: `&string`"#,
 
         assert!(messages[0].1.is_empty(), "{:?}", messages[0].1);
     }
+
+    /// ```
+    /// fn main() {
+    ///     let mut out = String::new();
+    ///     write!(out, "{}", 123);
+    /// }
+    /// ```
+    #[test]
+    fn macro_error_no_trait() {
+        let diag = parse_compiler_message(
+            include_str!("../../test_data/compiler_message/macro-error-no-trait.json"),
+            true,
+        );
+        assert_eq!(diag.diagnostics.len(), 1, "{:#?}", diag.diagnostics);
+
+        let file = &diag.diagnostics.keys().nth(0).unwrap();
+        assert!(file.to_str().unwrap().ends_with("src/main.rs"), "Unexpected file {:?}", file);
+
+        let diagnostic = &diag.diagnostics.values().nth(0).unwrap()[0];
+        assert_eq!(diagnostic.0.source, Some("rustc".into()));
+        assert_eq!(diagnostic.0.range, Range {
+            start: Position::new(2, 4),
+            end: Position::new(2, 27),
+        });
+
+        let messages = diag.to_messages();
+        assert_eq!(
+            messages[0].0,
+            "no method named `write_fmt` found for type `std::string::String` \
+            in the current scope\n\n\
+            help: items from traits can only be used if the trait is in scope"
+        );
+
+        assert!(messages[0].1.is_empty(), "{:?}", messages[0].1);
+    }
 }
 
 /// Tests for creating suggestions from the compilers json output
 #[cfg(test)]
 mod diagnostic_suggestion_test {
     use self::diagnostic_message_test::*;
     use super::*;
-    use ls_types;
+    use ls_types::Position;
 
     #[test]
     fn suggest_use_when_cannot_find_type() {
@@ -680,15 +722,11 @@ mod diagnostic_suggestion_test {
             "Line 15: Add `use std::collections::HashSet;\n`"
         );
 
-        let expected_position = ls_types::Position {
-            line: 14,
-            character: 0,
-        };
         assert_eq!(
             use_hash_set.range,
             Range {
-                start: expected_position,
-                end: expected_position,
+                start: Position::new(14, 0),
+                end: Position::new(14, 0),
             }
         );
     }
@@ -715,14 +753,8 @@ mod diagnostic_suggestion_test {
         assert_eq!(
             change_to_mut.range,
             Range {
-                start: ls_types::Position {
-                    line: 132,
-                    character: 12,
-                },
-                end: ls_types::Position {
-                    line: 132,
-                    character: 18,
-                },
+                start: Position::new(132, 12),
+                end: Position::new(132, 18),
             }
         );
     }
@@ -752,14 +784,35 @@ mod diagnostic_suggestion_test {
         assert_eq!(
             change_to_mut.range,
             Range {
-                start: ls_types::Position {
-                    line: 354,
-                    character: 34,
-                },
-                end: ls_types::Position {
-                    line: 354,
-                    character: 46,
-                },
+                start: Position::new(354, 34),
+                end: Position::new(354, 46),
+            }
+        );
+    }
+
+    #[test]
+    fn suggest_macro_error_no_trait() {
+        let diag = parse_compiler_message(
+            include_str!("../../test_data/compiler_message/macro-error-no-trait.json"),
+            true,
+        );
+        let diagnostics = diag.diagnostics.values().nth(0).unwrap();
+
+        eprintln!("{:#?}", diagnostics);
+
+        let change_to_mut = diagnostics
+            .iter()
+            .flat_map(|(_, suggestions)| suggestions)
+            .find(|s| s.new_text == "use std::fmt::Write;\n\n")
+            .expect("`use std::fmt::Write;` not found");
+
+        assert_eq!(change_to_mut.label, "Line 1: Add `use std::fmt::Write;\n\n`");
+
+        assert_eq!(
+            change_to_mut.range,
+            Range {
+                start: Position::new(0, 0),
+                end: Position::new(0, 0),
             }
         );
     }

test_data/compiler_message/macro-error-no-trait.json

@@ -0,0 +1,105 @@
+{
+  "children": [{
+    "children": [],
+    "code": null,
+    "level": "help",
+    "message": "items from traits can only be used if the trait is in scope",
+    "rendered": null,
+    "spans": []
+  }, {
+    "children": [],
+    "code": null,
+    "level": "help",
+    "message": "the following trait is implemented but not in scope, perhaps add a `use` for it:",
+    "rendered": null,
+    "spans": [{
+      "byte_end": 0,
+      "byte_start": 0,
+      "column_end": 1,
+      "column_start": 1,
+      "expansion": null,
+      "file_name": "src/main.rs",
+      "is_primary": true,
+      "label": null,
+      "line_end": 1,
+      "line_start": 1,
+      "suggested_replacement": "use std::fmt::Write;\n\n",
+      "suggestion_applicability": "Unspecified",
+      "text": [{
+        "highlight_end": 1,
+        "highlight_start": 1,
+        "text": "fn main() {"
+      }]
+    }]
+  }],
+  "code": {
+    "code": "E0599",
+    "explanation": "\nThis error occurs when a method is used on a type which doesn't implement it:\n\nErroneous code example:\n\n```compile_fail,E0599\nstruct Mouth;\n\nlet x = Mouth;\nx.chocolate(); // error: no method named `chocolate` found for type `Mouth`\n               //        in the current scope\n```\n"
+  },
+  "level": "error",
+  "message": "no method named `write_fmt` found for type `std::string::String` in the current scope",
+  "rendered": "error[E0599]: no method named `write_fmt` found for type `std::string::String` in the current scope\n --> src/main.rs:3:5\n  |\n3 |     write!(out, \"{}\", 123);\n  |     ^^^^^^^^^^^^^^^^^^^^^^^\n  |\n  = help: items from traits can only be used if the trait is in scope\n  = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)\nhelp: the following trait is implemented but not in scope, perhaps add a `use` for it:\n  |\n1 | use std::fmt::Write;\n  |\n\n",
+  "spans": [{
+    "byte_end": 60,
+    "byte_start": 51,
+    "column_end": 18,
+    "column_start": 9,
+    "expansion": {
+      "def_site_span": {
+        "byte_end": 98,
+        "byte_start": 0,
+        "column_end": 56,
+        "column_start": 1,
+        "expansion": null,
+        "file_name": "<write macros>",
+        "is_primary": false,
+        "label": null,
+        "line_end": 2,
+        "line_start": 1,
+        "suggested_replacement": null,
+        "suggestion_applicability": null,
+        "text": [{
+          "highlight_end": 43,
+          "highlight_start": 1,
+          "text": "( $ dst : expr , $ ( $ arg : tt ) * ) => ("
+        }, {
+          "highlight_end": 56,
+          "highlight_start": 1,
+          "text": "$ dst . write_fmt ( format_args ! ( $ ( $ arg ) * ) ) )"
+        }]
+      },
+      "macro_decl_name": "write!",
+      "span": {
+        "byte_end": 72,
+        "byte_start": 49,
+        "column_end": 28,
+        "column_start": 5,
+        "expansion": null,
+        "file_name": "src/main.rs",
+        "is_primary": false,
+        "label": null,
+        "line_end": 3,
+        "line_start": 3,
+        "suggested_replacement": null,
+        "suggestion_applicability": null,
+        "text": [{
+          "highlight_end": 28,
+          "highlight_start": 5,
+          "text": "    write!(out, \"{}\", 123);"
+        }]
+      }
+    },
+    "file_name": "<write macros>",
+    "is_primary": true,
+    "label": null,
+    "line_end": 2,
+    "line_start": 2,
+    "suggested_replacement": null,
+    "suggestion_applicability": null,
+    "text": [{
+      "highlight_end": 18,
+      "highlight_start": 9,
+      "text": "$ dst . write_fmt ( format_args ! ( $ ( $ arg ) * ) ) )"
+    }]
+  }]
+}