Improve code readability

src/librustdoc/doctest.rs

@@ -448,6 +448,12 @@ struct RunnableDoctest {
     no_run: bool,
 }
 
+impl RunnableDoctest {
+    fn path_for_merged_doctest(&self) -> PathBuf {
+        self.test_opts.outdir.path().join(&format!("doctest_{}.rs", self.edition))
+    }
+}
+
 fn run_test(
     doctest: RunnableDoctest,
     rustdoc_options: &RustdocOptions,
@@ -528,8 +534,7 @@ fn run_test(
     if is_multiple_tests {
         // It makes the compilation failure much faster if it is for a combined doctest.
         compiler.arg("--error-format=short");
-        let input_file =
-            doctest.test_opts.outdir.path().join(&format!("doctest_{}.rs", doctest.edition));
+        let input_file = doctest.path_for_merged_doctest();
         if std::fs::write(&input_file, &doctest.full_test_code).is_err() {
             // If we cannot write this file for any reason, we leave. All combined tests will be
             // tested as standalone tests.
@@ -809,9 +814,9 @@ impl CreateRunnableDoctests {
             edition,
             self.can_merge_doctests,
             Some(test_id),
+            Some(&scraped_test.langstr),
         );
-        let is_standalone = !self.can_merge_doctests
-            || !doctest.can_be_merged
+        let is_standalone = !doctest.can_be_merged
             || scraped_test.langstr.compile_fail
             || scraped_test.langstr.test_harness
             || scraped_test.langstr.standalone

src/librustdoc/doctest/make.rs

@@ -1,6 +1,8 @@
 //! Logic for transforming the raw code given by the user into something actually
 //! runnable, e.g. by adding a `main` function if it doesn't already exist.
 
+use crate::html::markdown::LangString;
+
 use std::io;
 
 use rustc_ast as ast;
@@ -42,7 +44,13 @@ impl DocTestBuilder {
         can_merge_doctests: bool,
         // If `test_id` is `None`, it means we're generating code for a code example "run" link.
         test_id: Option<String>,
+        lang_str: Option<&LangString>,
     ) -> Self {
+        let can_merge_doctests = can_merge_doctests
+            && lang_str.is_some_and(|lang_str| {
+                !lang_str.compile_fail && !lang_str.test_harness && !lang_str.standalone
+            });
+
         let SourceInfo { crate_attrs, maybe_crate_attrs, crates, everything_else } =
             partition_source(source, edition);
 

src/librustdoc/doctest/tests.rs

@@ -16,6 +16,7 @@ fn make_test(
         DEFAULT_EDITION,
         false,
         test_id.map(|s| s.to_string()),
+        None,
     );
     let (code, line_offset) =
         doctest.generate_unique_doctest(test_code, dont_insert_main, opts, crate_name);

src/librustdoc/html/markdown.rs

@@ -297,7 +297,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                 attrs: vec![],
                 args_file: PathBuf::new(),
             };
-            let doctest = doctest::DocTestBuilder::new(&test, krate, edition, false, None);
+            let doctest = doctest::DocTestBuilder::new(&test, krate, edition, false, None, None);
             let (test, _) = doctest.generate_unique_doctest(&test, false, &opts, krate);
             let channel = if test.contains("#![feature(") { "&amp;version=nightly" } else { "" };