Fix linking Rust error messages to source (#8345)

The compiler output pane only links error messages to the source editor
when a filename is given. `parseRustOutput` didn’t parse the filename,
so Rust error messages were never linked.

This PR also simplifies the regex used to parse the `-->
filename:line:column` line in the `rustc` output. As far as I’m aware
(and I checked the history of the corresponding output in the `rustc`
source), the output format will always be `--> filename:line:column` and
not anything else accepted by the previous regex (no parentheses around
the line number, the column is not optional).

lib/utils.ts

@@ -255,6 +255,7 @@ export function parseOutput(
 }
 
 export function parseRustOutput(lines: string, inputFilename?: string, pathPrefix?: string) {
+    const inputBasename = inputFilename ? path.basename(inputFilename) : undefined;
     const quickfixes: {re: RegExp; makeFix: (match: string[]) => Fix}[] = [
         {
             re: / *help: add `#!\[feature\((.*?)\)]`/,
@@ -288,7 +289,7 @@ export function parseRustOutput(lines: string, inputFilename?: string, pathPrefi
         },
     ];
 
-    const re = /^\s+-->\s+<source>[(:](\d+)(:?,?(\d+):?)?[):]*\s*(.*)/;
+    const re = /^\s+-->\s+(?<filename>.*):(?<line>\d+):(?<column>\d+)/;
     const result: ResultLine[] = [];
     let currentDiagnostic: ResultLine | undefined;
     eachLine(lines, line => {
@@ -298,14 +299,17 @@ export function parseRustOutput(lines: string, inputFilename?: string, pathPrefi
             const filteredLine = filterEscapeSequences(line);
             const match = filteredLine.match(re);
 
-            if (match) {
-                const line = Number.parseInt(match[1], 10);
-                const column = Number.parseInt(match[3] || '0', 10);
+            if (match?.groups) {
+                const file =
+                    match.groups.filename === '<source>' ? inputBasename : path.basename(match.groups.filename);
+                const line = Number.parseInt(match.groups.line, 10);
+                const column = Number.parseInt(match.groups.column, 10);
 
                 currentDiagnostic = result.pop();
                 if (currentDiagnostic !== undefined) {
                     const text = filterEscapeSequences(currentDiagnostic.text);
                     currentDiagnostic.tag = {
+                        file,
                         line,
                         column,
                         text,
@@ -316,6 +320,7 @@ export function parseRustOutput(lines: string, inputFilename?: string, pathPrefi
                 }
 
                 lineObj.tag = {
+                    file,
                     line,
                     column,
                     text: '', // Left empty so that it does not show up in the editor

test/utils-tests.ts

@@ -247,49 +247,49 @@ describe('Pascal compiler output', () => {
 describe('Rust compiler output', () => {
     it('handles simple cases', () => {
         expect(utils.parseRustOutput('Line one\nLine two', 'bob.rs')).toEqual([{text: 'Line one'}, {text: 'Line two'}]);
-        expect(utils.parseRustOutput('Unrelated\nLine one\n --> bob.rs:1\nUnrelated', 'bob.rs')).toEqual([
+        expect(utils.parseRustOutput('Unrelated\nLine one\n --> bob.rs:1:0\nUnrelated', 'bob.rs')).toEqual([
             {text: 'Unrelated'},
             {
-                tag: {column: 0, line: 1, text: 'Line one', severity: 3, fixes: []},
+                tag: {file: 'bob.rs', column: 0, line: 1, text: 'Line one', severity: 3, fixes: []},
                 text: 'Line one',
             },
             {
-                tag: {column: 0, line: 1, text: '', severity: 3},
-                text: ' --> <source>:1',
+                tag: {file: 'bob.rs', column: 0, line: 1, text: '', severity: 3},
+                text: ' --> <source>:1:0',
             },
             {text: 'Unrelated'},
         ]);
         expect(utils.parseRustOutput('Line one\n --> bob.rs:1:5', 'bob.rs')).toEqual([
             {
-                tag: {column: 5, line: 1, text: 'Line one', severity: 3, fixes: []},
+                tag: {file: 'bob.rs', column: 5, line: 1, text: 'Line one', severity: 3, fixes: []},
                 text: 'Line one',
             },
             {
-                tag: {column: 5, line: 1, text: '', severity: 3},
+                tag: {file: 'bob.rs', column: 5, line: 1, text: '', severity: 3},
                 text: ' --> <source>:1:5',
             },
         ]);
         expect(utils.parseRustOutput('Multiple spaces\n   --> bob.rs:1:5', 'bob.rs')).toEqual([
             {
-                tag: {column: 5, line: 1, text: 'Multiple spaces', severity: 3, fixes: []},
+                tag: {file: 'bob.rs', column: 5, line: 1, text: 'Multiple spaces', severity: 3, fixes: []},
                 text: 'Multiple spaces',
             },
             {
-                tag: {column: 5, line: 1, text: '', severity: 3},
+                tag: {file: 'bob.rs', column: 5, line: 1, text: '', severity: 3},
                 text: '   --> <source>:1:5',
             },
         ]);
     });
 
     it('replaces all references to input source', () => {
-        expect(utils.parseRustOutput('error: Error in bob.rs\n --> bob.rs:1', 'bob.rs')).toEqual([
+        expect(utils.parseRustOutput('error: Error in bob.rs\n --> bob.rs:1:42', 'bob.rs')).toEqual([
             {
-                tag: {column: 0, line: 1, text: 'error: Error in <source>', severity: 3, fixes: []},
+                tag: {file: 'bob.rs', column: 42, line: 1, text: 'error: Error in <source>', severity: 3, fixes: []},
                 text: 'error: Error in <source>',
             },
             {
-                tag: {column: 0, line: 1, text: '', severity: 3},
-                text: ' --> <source>:1',
+                tag: {file: 'bob.rs', column: 42, line: 1, text: '', severity: 3},
+                text: ' --> <source>:1:42',
             },
         ]);
     });
@@ -297,11 +297,11 @@ describe('Rust compiler output', () => {
     it('treats <stdin> as if it were the compiler source', () => {
         expect(utils.parseRustOutput('error: <stdin> is sad\n --> <stdin>:120:25', 'bob.rs')).toEqual([
             {
-                tag: {column: 25, line: 120, text: 'error: <source> is sad', severity: 3, fixes: []},
+                tag: {file: 'bob.rs', column: 25, line: 120, text: 'error: <source> is sad', severity: 3, fixes: []},
                 text: 'error: <source> is sad',
             },
             {
-                tag: {column: 25, line: 120, text: '', severity: 3},
+                tag: {file: 'bob.rs', column: 25, line: 120, text: '', severity: 3},
                 text: ' --> <source>:120:25',
             },
         ]);
@@ -412,6 +412,68 @@ describe('Rust compiler output', () => {
             {text: '   = help: add `#![feature(num_midpoint_signed)]` to the crate attributes to enable'},
         ]);
     });
+
+    it('attaches filenames to errors from multiple files', () => {
+        // https://godbolt.org/z/nWE3PTeGf
+        expect(
+            utils.parseRustOutput(
+                `warning: function \`f1\` is never used
+ --> <source>:3:4
+
+warning: function \`f2\` is never used
+ --> /app/m.rs:1:4
+
+warning: 2 warnings emitted`,
+                'example.rs',
+            ),
+        ).toEqual([
+            {
+                text: 'warning: function `f1` is never used',
+                tag: {
+                    line: 3,
+                    column: 4,
+                    file: 'example.rs',
+                    severity: 2,
+                    text: 'warning: function `f1` is never used',
+                    fixes: [],
+                },
+            },
+            {
+                text: ' --> <source>:3:4',
+                tag: {
+                    line: 3,
+                    column: 4,
+                    file: 'example.rs',
+                    severity: 3,
+                    text: '',
+                },
+            },
+            {text: ''},
+            {
+                text: 'warning: function `f2` is never used',
+                tag: {
+                    line: 1,
+                    column: 4,
+                    file: 'm.rs',
+                    severity: 2,
+                    text: 'warning: function `f2` is never used',
+                    fixes: [],
+                },
+            },
+            {
+                text: ' --> /app/m.rs:1:4',
+                tag: {
+                    line: 1,
+                    column: 4,
+                    file: 'm.rs',
+                    severity: 3,
+                    text: '',
+                },
+            },
+            {text: ''},
+            {text: 'warning: 2 warnings emitted'},
+        ]);
+    });
 });
 
 describe('Tool output', () => {