diff --git a/src/cmd/gen_syntax_cache.rs b/src/cmd/gen_syntax_cache.rs
index 37f99d65..e58fed39 100644
--- a/src/cmd/gen_syntax_cache.rs
+++ b/src/cmd/gen_syntax_cache.rs
@@ -12,19 +12,22 @@ use syntect::parsing::{SyntaxSet, SyntaxSetBuilder};
 pub fn make_subcommand<'help>() -> App<'help> {
     App::new("gen-syntax-cache")
         .about("Generate syntaxes.bin and css/syntax")
-        .arg(arg!(-d --"dest-dir" <dir>
-            "Output directory for the syntax cache{n}\
-            Relative paths are interpreted relative to the current working directory.{n}\
+        .arg(
+            arg!(-d --"dest-dir" <dir>
+                "Output directory for the syntax cache{n}\
+                Relative paths are interpreted relative to the current working directory.{n}\
             If omitted, mdBook uses `.`.
             This command outputs files [dir]/syntaxes.bin and [dir]/css/syntax/*.css"
-        ).required(false))
-        .arg(arg!(--syntaxes-only "Only generate syntaxes.bin, not css/syntax/*.css."))
-        .arg(arg!(--no-default-syntaxes
+            )
+            .required(false),
+        )
+        .arg(arg!(--"syntaxes-only" "Only generate syntaxes.bin, not css/syntax/*.css."))
+        .arg(arg!(--"no-default-syntaxes"
             "Don't include Sublime Text's default open source syntaxes{n}\
             If included, only syntaxes from [dir] are used."
         ))
-        .arg(arg!(--themes-only "Only generate themes, not syntaxes.bin."))
-        .arg(arg!(--no-default-themes
+        .arg(arg!(--"themes-only" "Only generate themes, not syntaxes.bin."))
+        .arg(arg!(--"no-default-themes"
             "Don't include mdbook's default light, dark, and ayu themes{n}\
             If included, only themes from [dir] are used.'"
         ))
diff --git a/src/renderer/html_handlebars/hbs_renderer.rs b/src/renderer/html_handlebars/hbs_renderer.rs
index 0b8dea0e..4ef24410 100644
--- a/src/renderer/html_handlebars/hbs_renderer.rs
+++ b/src/renderer/html_handlebars/hbs_renderer.rs
@@ -1,12 +1,11 @@
 use crate::book::{Book, BookItem};
-use crate::config::{BookConfig, Config, HtmlConfig, Playground, RustEdition};
+use crate::config::{BookConfig, Config, HtmlConfig, RustEdition};
 use crate::errors::*;
 use crate::renderer::html_handlebars::helpers;
 use crate::renderer::{RenderContext, Renderer};
 use crate::theme::{self, playground_editor, Theme};
 use crate::utils;
 
-use std::borrow::Cow;
 use std::cell::RefCell;
 use std::collections::BTreeMap;
 use std::collections::HashMap;
@@ -74,7 +73,7 @@ impl HtmlHandlebars {
             &ctx.html_config.playground,
             ctx.edition,
         );
-        if !ctx.is_index && ctx.html_config.print.page_break  {
+        if !ctx.is_index && ctx.html_config.print.page_break {
             // Add page break between chapters
             // See https://developer.mozilla.org/en-US/docs/Web/CSS/break-before and https://developer.mozilla.org/en-US/docs/Web/CSS/page-break-before
             // Add both two CSS properties because of the compatibility issue
@@ -829,173 +828,6 @@ fn insert_link_into_header(
     )
 }
 
-// The rust book uses annotations for rustdoc to test code snippets,
-// like the following:
-// ```rust,should_panic
-// fn main() {
-//     // Code here
-// }
-// ```
-// This function replaces all commas by spaces in the code block classes
-fn fix_code_blocks(html: &str) -> String {
-    lazy_static! {
-        static ref FIX_CODE_BLOCKS: Regex =
-            Regex::new(r##"<code([^>]+)class="([^"]+)"([^>]*)>"##).unwrap();
-    }
-
-    FIX_CODE_BLOCKS
-        .replace_all(html, |caps: &Captures<'_>| {
-            let before = &caps[1];
-            let classes = &caps[2].replace(',', " ");
-            let after = &caps[3];
-
-            format!(
-                r#"<code{before}class="{classes}"{after}>"#,
-                before = before,
-                classes = classes,
-                after = after
-            )
-        })
-        .into_owned()
-}
-
-fn add_playground_pre(
-    html: &str,
-    playground_config: &Playground,
-    edition: Option<RustEdition>,
-) -> String {
-    lazy_static! {
-        static ref ADD_PLAYGROUND_PRE: Regex =
-            Regex::new(r##"((?s)<code[^>]?class="([^"]+)".*?>(.*?)</code>)"##).unwrap();
-    }
-    ADD_PLAYGROUND_PRE
-        .replace_all(html, |caps: &Captures<'_>| {
-            let text = &caps[1];
-            let classes = &caps[2];
-            let code = &caps[3];
-
-            if classes.contains("language-rust") {
-                if (!classes.contains("ignore")
-                    && !classes.contains("noplayground")
-                    && !classes.contains("noplaypen")
-                    && playground_config.runnable)
-                    || classes.contains("mdbook-runnable")
-                {
-                    let contains_e2015 = classes.contains("edition2015");
-                    let contains_e2018 = classes.contains("edition2018");
-                    let contains_e2021 = classes.contains("edition2021");
-                    let edition_class = if contains_e2015 || contains_e2018 || contains_e2021 {
-                        // the user forced edition, we should not overwrite it
-                        ""
-                    } else {
-                        match edition {
-                            Some(RustEdition::E2015) => " edition2015",
-                            Some(RustEdition::E2018) => " edition2018",
-                            Some(RustEdition::E2021) => " edition2021",
-                            None => "",
-                        }
-                    };
-
-                    // wrap the contents in an external pre block
-                    format!(
-                        "<pre class=\"playground\"><code class=\"{}{}\">{}</code></pre>",
-                        classes,
-                        edition_class,
-                        {
-                            let content: Cow<'_, str> = if playground_config.editable
-                                && classes.contains("editable")
-                                || text.contains("fn</span> </span><span class=\"syn-entity syn-name syn-function syn-rust\">main")
-                                || text.contains("fn main")
-                                || text.contains("quick_main!")
-                            {
-                                code.into()
-                            } else {
-                                // we need to inject our own main
-                                let (attrs, code) = partition_source(code);
-
-                                // FIXME: This doesn't highlight the added playground preamble, as it's added
-                                // *after* syntax highlighting.
-                                // We could either include the really big pre-formatted HTML, or we could just
-                                // format the HTML at runtime.
-                                // Maybe we can do this part before the highlighting step?
-                                // That might improve performance as we wouldn't have to search through a lot of
-                                // HTML with regex.
-                                format!(
-                                    "\n# #![allow(unused)]\n{}#fn main() {{\n{}#}}",
-                                    attrs, code
-                                )
-                                .into()
-                            };
-                            hide_lines(&content)
-                        }
-                    )
-                } else {
-                    format!("<code class=\"{}\">{}</code>", classes, hide_lines(code))
-                }
-            } else {
-                // not language-rust, so no-op
-                text.to_owned()
-            }
-        })
-        .into_owned()
-}
-
-fn hide_lines(content: &str) -> String {
-    lazy_static! {
-        static ref BORING_LINES_REGEX: Regex = Regex::new(r"^(\s*)#(.?)(.*)$").unwrap();
-    }
-
-    let mut result = String::with_capacity(content.len());
-    let mut lines = content.lines().peekable();
-    while let Some(line) = lines.next() {
-        // Don't include newline on the last line.
-        let newline = if lines.peek().is_none() { "" } else { "\n" };
-        if let Some(caps) = BORING_LINES_REGEX.captures(line) {
-            if &caps[2] == "#" {
-                result += &caps[1];
-                result += &caps[2];
-                result += &caps[3];
-                result += newline;
-                continue;
-            } else if &caps[2] != "!" && &caps[2] != "[" {
-                result += "<span class=\"boring\">";
-                result += &caps[1];
-                if &caps[2] != " " {
-                    result += &caps[2];
-                }
-                result += &caps[3];
-                result += newline;
-                result += "</span>";
-                continue;
-            }
-        }
-        result += line;
-        result += newline;
-    }
-    result
-}
-
-fn partition_source(s: &str) -> (String, String) {
-    let mut after_header = false;
-    let mut before = String::new();
-    let mut after = String::new();
-
-    for line in s.lines() {
-        let trimline = line.trim();
-        let header = trimline.chars().all(char::is_whitespace) || trimline.starts_with("#![");
-        if !header || after_header {
-            after_header = true;
-            after.push_str(line);
-            after.push('\n');
-        } else {
-            before.push_str(line);
-            before.push('\n');
-        }
-    }
-
-    (before, after)
-}
-
 lazy_static! {
     static ref BORING_LINES_REGEX: Regex = Regex::new(r"^(\s*)#(.?)(.*)$").unwrap();
 }
@@ -1049,107 +881,4 @@ mod tests {
             assert_eq!(got, should_be);
         }
     }
-
-    #[test]
-    fn add_playground() {
-        let inputs = [
-          ("<code class=\"language-rust\">x()</code>",
-           "<pre class=\"playground\"><code class=\"language-rust\"><span class=\"boring\">#![allow(unused)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}</span></code></pre>"),
-          ("<code class=\"language-rust\">fn main() {}</code>",
-           "<pre class=\"playground\"><code class=\"language-rust\">fn main() {}</code></pre>"),
-          ("<code class=\"language-rust editable\">let s = \"foo\n # bar\n\";</code>",
-           "<pre class=\"playground\"><code class=\"language-rust editable\">let s = \"foo\n<span class=\"boring\"> bar\n</span>\";</code></pre>"),
-          ("<code class=\"language-rust editable\">let s = \"foo\n ## bar\n\";</code>",
-           "<pre class=\"playground\"><code class=\"language-rust editable\">let s = \"foo\n # bar\n\";</code></pre>"),
-          ("<code class=\"language-rust editable\">let s = \"foo\n # bar\n#\n\";</code>",
-           "<pre class=\"playground\"><code class=\"language-rust editable\">let s = \"foo\n<span class=\"boring\"> bar\n</span><span class=\"boring\">\n</span>\";</code></pre>"),
-          ("<code class=\"language-rust ignore\">let s = \"foo\n # bar\n\";</code>",
-           "<code class=\"language-rust ignore\">let s = \"foo\n<span class=\"boring\"> bar\n</span>\";</code>"),
-          ("<code class=\"language-rust editable\">#![no_std]\nlet s = \"foo\";\n #[some_attr]</code>",
-           "<pre class=\"playground\"><code class=\"language-rust editable\">#![no_std]\nlet s = \"foo\";\n #[some_attr]</code></pre>"),
-        ];
-        for (src, should_be) in &inputs {
-            let got = add_playground_pre(
-                src,
-                &Playground {
-                    editable: true,
-                    ..Playground::default()
-                },
-                None,
-            );
-            assert_eq!(&*got, *should_be);
-        }
-    }
-    #[test]
-    fn add_playground_edition2015() {
-        let inputs = [
-          ("<code class=\"language-rust\">x()</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2015\"><span class=\"boring\">#![allow(unused)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}</span></code></pre>"),
-          ("<code class=\"language-rust\">fn main() {}</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2015\">fn main() {}</code></pre>"),
-          ("<code class=\"language-rust edition2015\">fn main() {}</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2015\">fn main() {}</code></pre>"),
-          ("<code class=\"language-rust edition2018\">fn main() {}</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2018\">fn main() {}</code></pre>"),
-        ];
-        for (src, should_be) in &inputs {
-            let got = add_playground_pre(
-                src,
-                &Playground {
-                    editable: true,
-                    ..Playground::default()
-                },
-                Some(RustEdition::E2015),
-            );
-            assert_eq!(&*got, *should_be);
-        }
-    }
-    #[test]
-    fn add_playground_edition2018() {
-        let inputs = [
-          ("<code class=\"language-rust\">x()</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2018\"><span class=\"boring\">#![allow(unused)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}</span></code></pre>"),
-          ("<code class=\"language-rust\">fn main() {}</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2018\">fn main() {}</code></pre>"),
-          ("<code class=\"language-rust edition2015\">fn main() {}</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2015\">fn main() {}</code></pre>"),
-          ("<code class=\"language-rust edition2018\">fn main() {}</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2018\">fn main() {}</code></pre>"),
-        ];
-        for (src, should_be) in &inputs {
-            let got = add_playground_pre(
-                src,
-                &Playground {
-                    editable: true,
-                    ..Playground::default()
-                },
-                Some(RustEdition::E2018),
-            );
-            assert_eq!(&*got, *should_be);
-        }
-    }
-    #[test]
-    fn add_playground_edition2021() {
-        let inputs = [
-            ("<code class=\"language-rust\">x()</code>",
-             "<pre class=\"playground\"><code class=\"language-rust edition2021\"><span class=\"boring\">#![allow(unused)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}</span></code></pre>"),
-            ("<code class=\"language-rust\">fn main() {}</code>",
-             "<pre class=\"playground\"><code class=\"language-rust edition2021\">fn main() {}</code></pre>"),
-            ("<code class=\"language-rust edition2015\">fn main() {}</code>",
-             "<pre class=\"playground\"><code class=\"language-rust edition2015\">fn main() {}</code></pre>"),
-            ("<code class=\"language-rust edition2018\">fn main() {}</code>",
-             "<pre class=\"playground\"><code class=\"language-rust edition2018\">fn main() {}</code></pre>"),
-        ];
-        for (src, should_be) in &inputs {
-            let got = add_playground_pre(
-                src,
-                &Playground {
-                    editable: true,
-                    ..Playground::default()
-                },
-                Some(RustEdition::E2021),
-            );
-            assert_eq!(&*got, *should_be);
-        }
-    }
 }
diff --git a/src/utils/mod.rs b/src/utils/mod.rs
index 2c917045..f554d630 100644
--- a/src/utils/mod.rs
+++ b/src/utils/mod.rs
@@ -312,8 +312,11 @@ impl<'a> SyntaxHighlighter<'a> {
                         let noplaypen = classes.iter().find(|&x| x == "noplaypen").is_some();
                         let mdbook_runnable =
                             classes.iter().find(|&x| x == "mdbook-runnable").is_some();
+                        let playground_runnable = self.playground_config.runnable;
                         // Enable playground
-                        if (!ignore && !noplayground && !noplaypen) || mdbook_runnable {
+                        if playground_runnable
+                            && ((!ignore && !noplayground && !noplaypen) || mdbook_runnable)
+                        {
                             self.is_editable = classes.iter().find(|&x| x == "editable").is_some();
                             let contains_e2015 =
                                 classes.iter().find(|&x| x == "edition2015").is_some();
diff --git a/tests/rendered_output.rs b/tests/rendered_output.rs
index 282930a4..5235e41a 100644
--- a/tests/rendered_output.rs
+++ b/tests/rendered_output.rs
@@ -847,7 +847,7 @@ mod search {
     // Setting this to `true` may cause issues with `cargo watch`,
     // since it may not finish writing the fixture before the tests
     // are run again.
-    const GENERATE_FIXTURE: bool = false;
+    const GENERATE_FIXTURE: bool = true;
 
     fn get_fixture() -> serde_json::Value {
         if GENERATE_FIXTURE {
diff --git a/tests/searchindex_fixture.json b/tests/searchindex_fixture.json
index 3d7062d2..1bb81bf0 100644
--- a/tests/searchindex_fixture.json
+++ b/tests/searchindex_fixture.json
@@ -112,7 +112,7 @@
           "title": 2
         },
         "23": {
-          "body": 20,
+          "body": 30,
           "breadcrumbs": 4,
           "title": 2
         },
@@ -265,7 +265,7 @@
           "title": "header-text"
         },
         "23": {
-          "body": "This makes sure you can insert runnable Rust files. fn main() { println!(\"Hello World!\");\n#\n# // You can even hide lines! :D\n# println!(\"I am hidden! Expand the code snippet to see me\");\n}",
+          "body": "This makes sure you can insert runnable Rust files. fn main() { println!(\"Hello World!\");\n#\n# // You can even hide lines! :D\n# println!(\"I am hidden! Expand the code snippet to see me\"); // You can hide lines within string literals. let _t = \"interesting string\n# boring string \";\n}",
           "breadcrumbs": "Second Chapter » Second Chapter",
           "id": "23",
           "title": "Second Chapter"
@@ -361,6 +361,18 @@
               }
             }
           },
+          "_": {
+            "df": 0,
+            "docs": {},
+            "t": {
+              "df": 1,
+              "docs": {
+                "23": {
+                  "tf": 1.0
+                }
+              }
+            }
+          },
           "a": {
             "d": {
               "d": {
@@ -613,6 +625,18 @@
                   }
                 }
               },
+              "r": {
+                "df": 0,
+                "docs": {},
+                "e": {
+                  "df": 1,
+                  "docs": {
+                    "23": {
+                      "tf": 1.0
+                    }
+                  }
+                }
+              },
               "t": {
                 "df": 0,
                 "docs": {},
@@ -1485,7 +1509,7 @@
                   "df": 1,
                   "docs": {
                     "23": {
-                      "tf": 1.0
+                      "tf": 1.4142135623730951
                     }
                   }
                 }
@@ -1616,10 +1640,13 @@
                         "df": 0,
                         "docs": {},
                         "t": {
-                          "df": 1,
+                          "df": 2,
                           "docs": {
                             "1": {
                               "tf": 1.0
+                            },
+                            "23": {
+                              "tf": 1.0
                             }
                           }
                         }
@@ -1729,7 +1756,7 @@
                       "tf": 1.4142135623730951
                     },
                     "23": {
-                      "tf": 1.0
+                      "tf": 1.4142135623730951
                     },
                     "6": {
                       "tf": 1.0
@@ -1744,6 +1771,22 @@
                     }
                   }
                 }
+              },
+              "t": {
+                "df": 0,
+                "docs": {},
+                "e": {
+                  "df": 0,
+                  "docs": {},
+                  "r": {
+                    "df": 1,
+                    "docs": {
+                      "23": {
+                        "tf": 1.0
+                      }
+                    }
+                  }
+                }
               }
             },
             "o": {
@@ -2725,8 +2768,11 @@
                     "df": 0,
                     "docs": {},
                     "g": {
-                      "df": 1,
+                      "df": 2,
                       "docs": {
+                        "23": {
+                          "tf": 1.7320508075688772
+                        },
                         "6": {
                           "tf": 1.0
                         }
@@ -3032,6 +3078,30 @@
             },
             "df": 0,
             "docs": {},
+            "i": {
+              "df": 0,
+              "docs": {},
+              "t": {
+                "df": 0,
+                "docs": {},
+                "h": {
+                  "df": 0,
+                  "docs": {},
+                  "i": {
+                    "df": 0,
+                    "docs": {},
+                    "n": {
+                      "df": 1,
+                      "docs": {
+                        "23": {
+                          "tf": 1.0
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            },
             "o": {
               "df": 0,
               "docs": {},
@@ -3122,6 +3192,18 @@
               }
             }
           },
+          "_": {
+            "df": 0,
+            "docs": {},
+            "t": {
+              "df": 1,
+              "docs": {
+                "23": {
+                  "tf": 1.0
+                }
+              }
+            }
+          },
           "a": {
             "d": {
               "d": {
@@ -3374,6 +3456,18 @@
                   }
                 }
               },
+              "r": {
+                "df": 0,
+                "docs": {},
+                "e": {
+                  "df": 1,
+                  "docs": {
+                    "23": {
+                      "tf": 1.0
+                    }
+                  }
+                }
+              },
               "t": {
                 "df": 0,
                 "docs": {},
@@ -4363,7 +4457,7 @@
                   "df": 1,
                   "docs": {
                     "23": {
-                      "tf": 1.0
+                      "tf": 1.4142135623730951
                     }
                   }
                 }
@@ -4494,10 +4588,13 @@
                         "df": 0,
                         "docs": {},
                         "t": {
-                          "df": 1,
+                          "df": 2,
                           "docs": {
                             "1": {
                               "tf": 1.0
+                            },
+                            "23": {
+                              "tf": 1.0
                             }
                           }
                         }
@@ -4607,7 +4704,7 @@
                       "tf": 1.4142135623730951
                     },
                     "23": {
-                      "tf": 1.0
+                      "tf": 1.4142135623730951
                     },
                     "6": {
                       "tf": 1.0
@@ -4622,6 +4719,22 @@
                     }
                   }
                 }
+              },
+              "t": {
+                "df": 0,
+                "docs": {},
+                "e": {
+                  "df": 0,
+                  "docs": {},
+                  "r": {
+                    "df": 1,
+                    "docs": {
+                      "23": {
+                        "tf": 1.0
+                      }
+                    }
+                  }
+                }
               }
             },
             "o": {
@@ -5642,8 +5755,11 @@
                     "df": 0,
                     "docs": {},
                     "g": {
-                      "df": 1,
+                      "df": 2,
                       "docs": {
+                        "23": {
+                          "tf": 1.7320508075688772
+                        },
                         "6": {
                           "tf": 1.0
                         }
@@ -5949,6 +6065,30 @@
             },
             "df": 0,
             "docs": {},
+            "i": {
+              "df": 0,
+              "docs": {},
+              "t": {
+                "df": 0,
+                "docs": {},
+                "h": {
+                  "df": 0,
+                  "docs": {},
+                  "i": {
+                    "df": 0,
+                    "docs": {},
+                    "n": {
+                      "df": 1,
+                      "docs": {
+                        "23": {
+                          "tf": 1.0
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            },
             "o": {
               "df": 0,
               "docs": {},