format string highlighting: handle hex + debug type specifier

Author: ruabmbua

crates/ide/src/syntax_highlighting/test_data/highlight_strings.html

@@ -93,4 +93,6 @@
 
     <span class="macro">println!</span><span class="punctuation">(</span><span class="string_literal">"</span><span class="format_specifier">{</span><span class="escape_sequence">\x41</span><span class="format_specifier">}</span><span class="string_literal">"</span><span class="punctuation">,</span> A <span class="operator">=</span> <span class="numeric_literal">92</span><span class="punctuation">)</span><span class="punctuation">;</span>
     <span class="macro">println!</span><span class="punctuation">(</span><span class="string_literal">"</span><span class="format_specifier">{</span><span class="variable">ничоси</span><span class="format_specifier">}</span><span class="string_literal">"</span><span class="punctuation">,</span> ничоси <span class="operator">=</span> <span class="numeric_literal">92</span><span class="punctuation">)</span><span class="punctuation">;</span>
+
+    <span class="macro">println!</span><span class="punctuation">(</span><span class="string_literal">"</span><span class="format_specifier">{</span><span class="format_specifier">:</span><span class="variable">x</span><span class="format_specifier">?</span><span class="format_specifier">}</span><span class="string_literal"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal"> "</span><span class="punctuation">,</span> thingy<span class="punctuation">,</span> n2<span class="punctuation">)</span><span class="punctuation">;</span>
 <span class="punctuation">}</span></code></pre>

crates/ide/src/syntax_highlighting/tests.rs

@@ -340,6 +340,8 @@ fn main() {
 
     println!("{\x41}", A = 92);
     println!("{ничоси}", ничоси = 92);
+
+    println!("{:x?} {} ", thingy, n2);
 }"#
         .trim(),
         expect_file!["./test_data/highlight_strings.html"],

crates/syntax/src/ast/token_ext.rs

@@ -331,10 +331,22 @@ pub trait HasFormatSpecifier: AstToken {
                             }
                             c if c == '_' || c.is_alphabetic() => {
                                 read_identifier(&mut chars, &mut callback);
+
+                                if chars.peek().and_then(|next| next.1.as_ref().ok()).copied()
+                                    == Some('?')
+                                {
+                                    skip_char_and_emit(
+                                        &mut chars,
+                                        FormatSpecifier::QuestionMark,
+                                        &mut callback,
+                                    );
+                                }
+
                                 // can be either width (indicated by dollar sign, or type in which case
                                 // the next sign has to be `}`)
                                 let next =
                                     chars.peek().and_then(|next| next.1.as_ref().ok()).copied();
+
                                 match next {
                                     Some('$') => skip_char_and_emit(
                                         &mut chars,
@@ -417,6 +429,16 @@ pub trait HasFormatSpecifier: AstToken {
                             }
                             c if c == '_' || c.is_alphabetic() => {
                                 read_identifier(&mut chars, &mut callback);
+
+                                if chars.peek().and_then(|next| next.1.as_ref().ok()).copied()
+                                    == Some('?')
+                                {
+                                    skip_char_and_emit(
+                                        &mut chars,
+                                        FormatSpecifier::QuestionMark,
+                                        &mut callback,
+                                    );
+                                }
                             }
                             _ => {}
                         }