Ignore strings in token trees in syntax highlighting

4 files changed, 30 insertions, 8 deletions

diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index d2fd63428b4..ac70c27785c 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -606,8 +606,8 @@ impl<'db> SemanticsImpl<'db> {
                 }
                 Dp::None => true,
             };
+            res = value;
             if is_a_match {
-                res = value;
                 ControlFlow::Break(())
             } else {
                 ControlFlow::Continue(())
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index 45582f54b46..366a3c969f9 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -393,13 +393,25 @@ fn traverse(
             // Attempt to descend tokens into macro-calls.
             let res = match element {
                 NodeOrToken::Token(token) if token.kind() != COMMENT => {
-                    let token = sema.descend_into_macros_single(
-                        match attr_or_derive_item {
-                            Some(AttrOrDerive::Attr(_)) => DescendPreference::SameKind,
-                            Some(AttrOrDerive::Derive(_)) | None => DescendPreference::None,
-                        },
-                        token,
-                    );
+                    let token = if token.kind() == STRING {
+                        // for strings, try to prefer a string that has not been lost in a token
+                        // tree
+                        // FIXME: This should be done for everything, but check perf first
+                        sema.descend_into_macros(DescendPreference::SameKind, token)
+                            .into_iter()
+                            .max_by_key(|it| {
+                                it.parent().map_or(false, |it| it.kind() != TOKEN_TREE)
+                            })
+                            .unwrap()
+                    } else {
+                        sema.descend_into_macros_single(
+                            match attr_or_derive_item {
+                                Some(AttrOrDerive::Attr(_)) => DescendPreference::SameKind,
+                                Some(AttrOrDerive::Derive(_)) | None => DescendPreference::None,
+                            },
+                            token,
+                        )
+                    };
                     match token.parent().and_then(ast::NameLike::cast) {
                         // Remap the token into the wrapping single token nodes
                         Some(parent) => match (token.kind(), parent.syntax().kind()) {
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html b/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
index b40295684df..75cb6223e0e 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlight_strings.html
@@ -76,6 +76,10 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="parenthesis">(</span><span class="punctuation">$</span><span class="parenthesis">(</span><span class="punctuation">$</span>arg<span class="colon">:</span>tt<span class="parenthesis">)</span><span class="punctuation">+</span><span class="parenthesis">)</span> <span class="operator">=</span><span class="angle">&gt;</span> <span class="parenthesis">(</span><span class="punctuation">$</span>crate<span class="colon">:</span><span class="colon">:</span>panic<span class="punctuation">!</span><span class="parenthesis">(</span><span class="string_literal">"not yet implemented: {}"</span><span class="comma">,</span> format_args<span class="punctuation">!</span><span class="parenthesis">(</span><span class="punctuation">$</span><span class="parenthesis">(</span><span class="punctuation">$</span>arg<span class="parenthesis">)</span><span class="punctuation">+</span><span class="parenthesis">)</span><span class="parenthesis">)</span><span class="parenthesis">)</span><span class="semicolon">;</span>
 <span class="brace">}</span>
 
+<span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration">reuse_twice</span> <span class="brace">{</span>
+    <span class="parenthesis">(</span><span class="punctuation">$</span>literal<span class="colon">:</span>literal<span class="parenthesis">)</span> <span class="operator">=</span><span class="angle">&gt;</span> <span class="brace">{</span><span class="brace">{</span>stringify<span class="punctuation">!</span><span class="parenthesis">(</span><span class="punctuation">$</span>literal<span class="parenthesis">)</span><span class="semicolon">;</span> format_args<span class="punctuation">!</span><span class="parenthesis">(</span><span class="punctuation">$</span>literal<span class="parenthesis">)</span><span class="brace">}</span><span class="brace">}</span><span class="semicolon">;</span>
+<span class="brace">}</span>
+
 <span class="keyword">fn</span> <span class="function declaration">main</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span>
     <span class="keyword">let</span> <span class="variable declaration">a</span> <span class="operator">=</span> <span class="char_literal">'</span><span class="escape_sequence">\n</span><span class="char_literal">'</span><span class="semicolon">;</span>
     <span class="keyword">let</span> <span class="variable declaration">a</span> <span class="operator">=</span> <span class="char_literal">'</span><span class="escape_sequence">\t</span><span class="char_literal">'</span><span class="semicolon">;</span>
@@ -170,4 +174,5 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable declaration mutable">m</span> <span class="operator">=</span> <span class="parenthesis">(</span><span class="parenthesis">)</span><span class="semicolon">;</span>
     <span class="macro default_library library">format_args</span><span class="macro_bang">!</span><span class="parenthesis macro">(</span><span class="macro default_library library macro">concat</span><span class="macro_bang macro">!</span><span class="parenthesis macro">(</span><span class="string_literal macro">"{}"</span><span class="parenthesis macro">)</span><span class="comma macro">,</span> <span class="string_literal macro">"{}"</span><span class="parenthesis macro">)</span><span class="semicolon">;</span>
     <span class="macro default_library library">format_args</span><span class="macro_bang">!</span><span class="parenthesis macro">(</span><span class="string_literal macro">"</span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal macro"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal macro"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal macro"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal macro"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal macro"> </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal macro"> </span><span class="format_specifier">{</span><span class="variable reference">backslash</span><span class="format_specifier">}</span><span class="string_literal macro"> </span><span class="format_specifier">{</span><span class="constant">CONSTANT</span><span class="format_specifier">}</span><span class="string_literal macro"> </span><span class="format_specifier">{</span><span class="variable mutable">m</span><span class="format_specifier">}</span><span class="string_literal macro">"</span><span class="comma macro">,</span> <span class="variable macro reference">backslash</span><span class="comma macro">,</span> <span class="macro default_library library macro">format_args</span><span class="macro_bang macro">!</span><span class="parenthesis macro">(</span><span class="string_literal macro">"</span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal macro">"</span><span class="comma macro">,</span> <span class="numeric_literal macro">0</span><span class="parenthesis macro">)</span><span class="comma macro">,</span> <span class="unresolved_reference macro">foo</span><span class="comma macro">,</span> <span class="string_literal macro">"bar"</span><span class="comma macro">,</span> <span class="macro macro">toho</span><span class="macro_bang macro">!</span><span class="parenthesis macro">(</span><span class="parenthesis macro">)</span><span class="comma macro">,</span> <span class="variable macro reference">backslash</span><span class="parenthesis macro">)</span><span class="semicolon">;</span>
+    <span class="macro">reuse_twice</span><span class="macro_bang">!</span><span class="parenthesis macro">(</span><span class="string_literal macro">"</span><span class="format_specifier">{</span><span class="variable reference">backslash</span><span class="format_specifier">}</span><span class="string_literal macro">"</span><span class="parenthesis macro">)</span><span class="semicolon">;</span>
 <span class="brace">}</span></code></pre>
\ No newline at end of file
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index 935b6b2cb9b..fcfd3c92571 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -430,6 +430,10 @@ macro_rules! toho {
     ($($arg:tt)+) => ($crate::panic!("not yet implemented: {}", format_args!($($arg)+)));
 }
 
+macro_rules! reuse_twice {
+    ($literal:literal) => {{stringify!($literal); format_args!($literal)}};
+}
+
 fn main() {
     let a = '\n';
     let a = '\t';
@@ -524,6 +528,7 @@ fn main() {
     let mut m = ();
     format_args!(concat!("{}"), "{}");
     format_args!("{} {} {} {} {} {} {backslash} {CONSTANT} {m}", backslash, format_args!("{}", 0), foo, "bar", toho!(), backslash);
+    reuse_twice!("{backslash}");
 }"#,
         expect_file!["./test_data/highlight_strings.html"],
         false,