Test diagnostic ranges, instead of only the start

Author: LeonMatthes

docs/testing.md

@@ -10,14 +10,14 @@ The syntax tests are testing that the compiler show the right error messages in
 The syntax tests are located in [internal/compiler/tests/syntax/](../internal/compiler/tests/syntax/) and it's driven by the
 [`syntax_tests.rs`](../internal/compiler/tests/syntax_tests.rs) file. More info in the comments of that file.
 
-In summary, each .slint files have comments with `^error` like so:
+In summary, each .slint files have comments with `> <error` like so:
 
 ```ignore
 foo bar
-//  ^error{parse error}
+//  > <error{parse error}
 ```
 
-Meaning that there must be an error on the line above at the location pointed by the caret.
+Meaning that there must be an error on the line above spanning `bar`, as indicated by the `>` and `<` arrows.
 
 Ideally, each error message must be tested like so.
 

internal/compiler/parser.rs

@@ -694,9 +694,7 @@ impl Parser for DefaultParser<'_> {
     fn error(&mut self, e: impl Into<String>) {
         let current_token = self.current_token();
         #[allow(unused_mut)]
-        let mut span = crate::diagnostics::Span::new(
-            current_token.offset,
-            current_token.length);
+        let mut span = crate::diagnostics::Span::new(current_token.offset, current_token.length);
         #[cfg(feature = "proc_macro_span")]
         {
             span.span = current_token.span;
@@ -715,9 +713,7 @@ impl Parser for DefaultParser<'_> {
     fn warning(&mut self, e: impl Into<String>) {
         let current_token = self.current_token();
         #[allow(unused_mut)]
-        let mut span = crate::diagnostics::Span::new(
-            current_token.offset,
-            current_token.length);
+        let mut span = crate::diagnostics::Span::new(current_token.offset, current_token.length);
         #[cfg(feature = "proc_macro_span")]
         {
             span.span = current_token.span;
@@ -953,9 +949,7 @@ impl NodeOrToken {
 impl Spanned for SyntaxNode {
     fn span(&self) -> crate::diagnostics::Span {
         let range = self.node.text_range();
-        crate::diagnostics::Span::new(
-            range.start().into(),
-            range.len().into())
+        crate::diagnostics::Span::new(range.start().into(), range.len().into())
     }
 
     fn source_file(&self) -> Option<&SourceFile> {
@@ -976,9 +970,7 @@ impl Spanned for Option<SyntaxNode> {
 impl Spanned for SyntaxToken {
     fn span(&self) -> crate::diagnostics::Span {
         let range = self.token.text_range();
-        crate::diagnostics::Span::new(
-            range.start().into(),
-            range.len().into())
+        crate::diagnostics::Span::new(range.start().into(), range.len().into())
     }
 
     fn source_file(&self) -> Option<&SourceFile> {

internal/compiler/tests/syntax/expressions/noops.slint

@@ -14,16 +14,18 @@ enum MyEnum {
 export component Test {
     function useless_if(cond: bool) {
         if (cond) {
-//      ^warning{Expression has no effect!}
+//      >warning{Expression has no effect!}
             if (!cond) {
-//          ^warning{Expression has no effect!}
+//          >warning{Expression has no effect!}
                 43
             }
+//          <warning{Expression has no effect!}
             42
         }
         else {
             41
         }
+//      <warning{Expression has no effect!}
         "hello world";
 //      ^warning{Expression has no effect!}
         123;