Make diagnostic locus point to the first primary label (#260)

codespan-reporting/assets/readme_preview.svg

@@ -52,7 +52,7 @@
   <foreignObject x="0" y="0" width="882" height="335">
     <div xmlns="http://www.w3.org/1999/xhtml">
       <pre><span class="fg red bold bright">error[E0308]</span><span class="bold bright">: `case` clauses have incompatible types</span>
-   <span class="fg blue">┌─</span> FizzBuzz.fun:10:15
+   <span class="fg blue">┌─</span> FizzBuzz.fun:16:16
    <span class="fg blue">│</span>  
 <span class="fg blue">10</span> <span class="fg blue">│</span>   fizz₂ : Nat → String
    <span class="fg blue">│</span>                 <span class="fg blue">------</span> <span class="fg blue">expected type `String` found here</span>

codespan-reporting/examples/readme_preview.rs

@@ -81,7 +81,10 @@ fn main() -> anyhow::Result<()> {
         Opts::Svg => {
             let mut buffer = Vec::new();
             let mut writer = HtmlEscapeWriter::new(SvgWriter::new(&mut buffer));
-            let config = codespan_reporting::term::Config::default();
+            let config = codespan_reporting::term::Config {
+                styles: codespan_reporting::term::Styles::with_blue(Color::Blue),
+                ..codespan_reporting::term::Config::default()
+            };
 
             for diagnostic in &diagnostics {
                 term::emit(&mut writer, &config, &file, &diagnostic)?;

codespan-reporting/src/diagnostic.rs

@@ -50,7 +50,7 @@ impl PartialOrd for Severity {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd)]
 #[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
 pub enum LabelStyle {
     /// Labels that describe the primary cause of a diagnostic.
@@ -112,6 +112,8 @@ impl<FileId> Label<FileId> {
 
 /// Represents a diagnostic message that can provide information like errors and
 /// warnings to the user.
+///
+/// The position of a Diagnostic is considered to be the position of the [`Label`] with a style of [`LabelStyle::primary`] that has the smallest start position.
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
 pub struct Diagnostic<FileId> {

codespan-reporting/src/term/views.rs

@@ -45,6 +45,7 @@ where
             location: Location,
             num_multi_labels: usize,
             lines: BTreeMap<usize, Line<'diagnostic>>,
+            max_label_style: LabelStyle,
         }
 
         impl<'diagnostic, FileId> LabeledFile<'diagnostic, FileId> {
@@ -103,14 +104,20 @@ where
                 .find(|labeled_file| label.file_id == labeled_file.file_id)
             {
                 Some(labeled_file) => {
-                    if labeled_file.start > label.range.start {
+                    // another diagnostic also referenced this file
+                    if labeled_file.start > label.range.start
+                        && labeled_file.max_label_style >= label.style
+                    {
+                        // this label indicates an earlier start and has at least the same level of style
                         labeled_file.start = label.range.start;
                         labeled_file.location =
                             files.location(label.file_id, label.range.start).unwrap();
+                        labeled_file.max_label_style = label.style;
                     }
                     labeled_file
                 }
                 None => {
+                    // no other diagnostic referenced this file yet
                     labeled_files.push(LabeledFile {
                         file_id: label.file_id,
                         start: label.range.start,
@@ -118,6 +125,7 @@ where
                         location: files.location(label.file_id, label.range.start).unwrap(),
                         num_multi_labels: 0,
                         lines: BTreeMap::new(),
+                        max_label_style: label.style,
                     });
                     labeled_files.last_mut().unwrap()
                 }

codespan-reporting/tests/snapshots/term__fizz_buzz__rich_color.snap

@@ -3,7 +3,7 @@ source: codespan-reporting/tests/term.rs
 expression: TEST_DATA.emit_color(&config)
 ---
 {fg:Red bold bright}error[E0308]{bold bright}: `case` clauses have incompatible types{/}
-  {fg:Blue}┌─{/} FizzBuzz.fun:3:15
+  {fg:Blue}┌─{/} FizzBuzz.fun:8:12
   {fg:Blue}│{/}  
 {fg:Blue}3{/} {fg:Blue}│{/}   fizz₁ : Nat → String
   {fg:Blue}│{/}                 {fg:Blue}------{/} {fg:Blue}expected type `String` found here{/}
@@ -20,7 +20,7 @@ expression: TEST_DATA.emit_color(&config)
        found type `Nat`
 
 {fg:Red bold bright}error[E0308]{bold bright}: `case` clauses have incompatible types{/}
-   {fg:Blue}┌─{/} FizzBuzz.fun:10:15
+   {fg:Blue}┌─{/} FizzBuzz.fun:16:16
    {fg:Blue}│{/}  
 {fg:Blue}10{/} {fg:Blue}│{/}   fizz₂ : Nat → String
    {fg:Blue}│{/}                 {fg:Blue}------{/} {fg:Blue}expected type `String` found here{/}

codespan-reporting/tests/snapshots/term__fizz_buzz__rich_no_color.snap

@@ -3,7 +3,7 @@ source: codespan-reporting/tests/term.rs
 expression: TEST_DATA.emit_no_color(&config)
 ---
 error[E0308]: `case` clauses have incompatible types
-  ┌─ FizzBuzz.fun:3:15
+  ┌─ FizzBuzz.fun:8:12
   │  
 3 │   fizz₁ : Nat → String
   │                 ------ expected type `String` found here
@@ -20,7 +20,7 @@ error[E0308]: `case` clauses have incompatible types
        found type `Nat`
 
 error[E0308]: `case` clauses have incompatible types
-   ┌─ FizzBuzz.fun:10:15
+   ┌─ FizzBuzz.fun:16:16
    │  
 10 │   fizz₂ : Nat → String
    │                 ------ expected type `String` found here

codespan-reporting/tests/snapshots/term__multiline_overlapping__rich_color.snap

@@ -3,7 +3,7 @@ source: codespan-reporting/tests/term.rs
 expression: TEST_DATA.emit_color(&config)
 ---
 {fg:Red bold bright}error[E0308]{bold bright}: match arms have incompatible types{/}
-  {fg:Blue}┌─{/} codespan/src/file.rs:1:9
+  {fg:Blue}┌─{/} codespan/src/file.rs:4:34
   {fg:Blue}│{/}    
 {fg:Blue}1{/} {fg:Blue}│{/}   {fg:Blue}╭{/}         match line_index.compare(self.last_line_index()) {
 {fg:Blue}2{/} {fg:Blue}│{/}   {fg:Blue}│{/}             Ordering::Less => Ok(self.line_starts()[line_index.to_usize()]),

codespan-reporting/tests/snapshots/term__multiline_overlapping__rich_no_color.snap

@@ -3,7 +3,7 @@ source: codespan-reporting/tests/term.rs
 expression: TEST_DATA.emit_no_color(&config)
 ---
 error[E0308]: match arms have incompatible types
-  ┌─ codespan/src/file.rs:1:9
+  ┌─ codespan/src/file.rs:4:34
   │    
 1 │   ╭         match line_index.compare(self.last_line_index()) {
 2 │   │             Ordering::Less => Ok(self.line_starts()[line_index.to_usize()]),

codespan-reporting/tests/snapshots/term__overlapping__rich_color.snap

@@ -3,7 +3,7 @@ source: codespan-reporting/tests/term.rs
 expression: TEST_DATA.emit_color(&config)
 ---
 {fg:Red bold bright}error[E0666]{bold bright}: nested `impl Trait` is not allowed{/}
-  {fg:Blue}┌─{/} nested_impl_trait.rs:5:46
+  {fg:Blue}┌─{/} nested_impl_trait.rs:5:56
   {fg:Blue}│{/}
 {fg:Blue}5{/} {fg:Blue}│{/} fn bad_in_ret_position(x: impl Into<u32>) -> impl Into<{fg:Red}impl Debug{/}> { x }
   {fg:Blue}│{/}                                              {fg:Blue}----------{fg:Red}^^^^^^^^^^{fg:Blue}-{/}
@@ -21,7 +21,7 @@ expression: TEST_DATA.emit_color(&config)
   {fg:Blue}│{/}                  {fg:Blue}help: replace with the correct return type: `i32`{/}
 
 {fg:Red bold bright}error[E0121]{bold bright}: the type placeholder `_` is not allowed within types on item signatures{/}
-  {fg:Blue}┌─{/} typeck_type_placeholder_item.rs:2:24
+  {fg:Blue}┌─{/} typeck_type_placeholder_item.rs:2:25
   {fg:Blue}│{/}
 {fg:Blue}2{/} {fg:Blue}│{/} fn fn_test2(x: i32) -> ({fg:Red}_{/}, {fg:Red}_{/}) { (x, x) }
   {fg:Blue}│{/}                        {fg:Blue}-{fg:Red}^{fg:Blue}--{fg:Red}^{fg:Blue}-{/}

codespan-reporting/tests/snapshots/term__overlapping__rich_no_color.snap

@@ -3,7 +3,7 @@ source: codespan-reporting/tests/term.rs
 expression: TEST_DATA.emit_no_color(&config)
 ---
 error[E0666]: nested `impl Trait` is not allowed
-  ┌─ nested_impl_trait.rs:5:46
+  ┌─ nested_impl_trait.rs:5:56
   │
 5 │ fn bad_in_ret_position(x: impl Into<u32>) -> impl Into<impl Debug> { x }
   │                                              ----------^^^^^^^^^^-
@@ -21,7 +21,7 @@ error[E0121]: the type placeholder `_` is not allowed within types on item signa
   │                  help: replace with the correct return type: `i32`
 
 error[E0121]: the type placeholder `_` is not allowed within types on item signatures
-  ┌─ typeck_type_placeholder_item.rs:2:24
+  ┌─ typeck_type_placeholder_item.rs:2:25
   │
 2 │ fn fn_test2(x: i32) -> (_, _) { (x, x) }
   │                        -^--^-

codespan-reporting/tests/snapshots/term__position_indicator__rich_no_color.snap

@@ -0,0 +1,14 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_no_color(&config)
+---
+warning[ParserWarning]: The strict mode declaration in the body of function `foo` is redundant, as the outer scope is already in strict mode
+  ┌─ tests/main.js:4:3
+  │
+1 │ "use strict";
+  │ ------------ Strict mode is first declared here
+  ·
+4 │   "use strict";
+  │   ^^^^^^^^^^^^ This strict mode declaration is redundant
+
+

codespan-reporting/tests/snapshots/term__position_indicator__short_no_color.snap

@@ -0,0 +1,6 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_no_color(&config)
+---
+tests/main.js:4:3: warning[ParserWarning]: The strict mode declaration in the body of function `foo` is redundant, as the outer scope is already in strict mode
+

codespan-reporting/tests/snapshots/term__same_line__rich_color.snap

@@ -3,7 +3,7 @@ source: codespan-reporting/tests/term.rs
 expression: TEST_DATA.emit_color(&config)
 ---
 {fg:Red bold bright}error[E0499]{bold bright}: cannot borrow `v` as mutable more than once at a time{/}
-  {fg:Blue}┌─{/} one_line.rs:3:5
+  {fg:Blue}┌─{/} one_line.rs:3:12
   {fg:Blue}│{/}
 {fg:Blue}3{/} {fg:Blue}│{/}     v.push({fg:Red}v{/}.pop().unwrap());
   {fg:Blue}│{/}     {fg:Blue}-{/} {fg:Blue}----{/} {fg:Red}^{/} {fg:Red}second mutable borrow occurs here{/}

codespan-reporting/tests/snapshots/term__same_line__rich_no_color.snap

@@ -3,7 +3,7 @@ source: codespan-reporting/tests/term.rs
 expression: TEST_DATA.emit_no_color(&config)
 ---
 error[E0499]: cannot borrow `v` as mutable more than once at a time
-  ┌─ one_line.rs:3:5
+  ┌─ one_line.rs:3:12
   │
 3 │     v.push(v.pop().unwrap());
   │     - ---- ^ second mutable borrow occurs here

codespan-reporting/tests/term.rs

@@ -845,6 +845,41 @@ mod unicode_spans {
     test_emit!(short_no_color);
 }
 
+mod position_indicator {
+    use super::*;
+
+    lazy_static::lazy_static! {
+        static ref TEST_DATA: TestData<'static, SimpleFile<&'static str, String>> = {
+            let file = SimpleFile::new(
+                "tests/main.js",
+                [
+                    "\"use strict\";",
+                    "let zero=0;",
+                    "function foo() {",
+                    "  \"use strict\";",
+                    "  one=1;",
+                    "}",
+                ].join("\n"),
+            );
+            let diagnostics = vec![
+                Diagnostic::warning()
+                    .with_code("ParserWarning")
+                    .with_message("The strict mode declaration in the body of function `foo` is redundant, as the outer scope is already in strict mode")
+                    .with_labels(vec![
+                        Label::primary((), 45..57)
+                            .with_message("This strict mode declaration is redundant"),
+                        Label::secondary((), 0..12)
+                            .with_message("Strict mode is first declared here"),
+                    ]),
+            ];
+            TestData{files: file, diagnostics }
+        };
+    }
+
+    test_emit!(rich_no_color);
+    test_emit!(short_no_color);
+}
+
 mod multiline_omit {
     use super::*;