3 files changed, 183 insertions, 10 deletions

diff --git a/src/test/rustdoc-ui/invalid-syntax.rs b/src/test/rustdoc-ui/invalid-syntax.rs
index 537816be8d7..924e0386d31 100644
--- a/src/test/rustdoc-ui/invalid-syntax.rs
+++ b/src/test/rustdoc-ui/invalid-syntax.rs
@@ -1,7 +1,66 @@
 // compile-pass
-// compile-flags: --error-format=human
 
 /// ```
 /// \__________pkt->size___________/          \_result->size_/ \__pkt->size__/
 /// ```
 pub fn foo() {}
+
+/// ```
+///    |
+/// LL | use foobar::Baz;
+///    |     ^^^^^^ did you mean `baz::foobar`?
+/// ```
+pub fn bar() {}
+
+/// ```
+/// valid
+/// ```
+///
+/// ```
+/// \_
+/// ```
+///
+/// ```text
+/// "invalid
+/// ```
+pub fn valid_and_invalid() {}
+
+/// This is a normal doc comment, but...
+///
+/// There's a code block with bad syntax in it:
+///
+/// ```rust
+/// \_
+/// ```
+///
+/// Good thing we tested it!
+pub fn baz() {}
+
+/// Indented block start
+///
+///     code with bad syntax
+///     \_
+///
+/// Indented block end
+pub fn quux() {}
+
+/// Unclosed fence
+///
+/// ```
+/// slkdjf
+pub fn xyzzy() {}
+
+/// Indented code that contains a fence
+///
+///     ```
+pub fn blah() {}
+
+/// ```edition2018
+/// \_
+/// ```
+pub fn blargh() {}
+
+#[doc = "```"]
+/// \_
+#[doc = "```"]
+pub fn crazy_attrs() {}
diff --git a/src/test/rustdoc-ui/invalid-syntax.stderr b/src/test/rustdoc-ui/invalid-syntax.stderr
index b5661332e8d..10800380a05 100644
--- a/src/test/rustdoc-ui/invalid-syntax.stderr
+++ b/src/test/rustdoc-ui/invalid-syntax.stderr
@@ -1,10 +1,97 @@
-Output from rustc:
-error: unknown start of token: /
- --> <stdin>:1:1
-  |
-1 | /__________pkt->size___________/          /_result->size_/ /__pkt->size__/
-  | ^
-
-warning: Invalid doc comment starting with: `/__________pkt->size___________/          /_result->size_/ /__pkt->size__/`
-(Ignoring this codeblock)
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:3:5
+   |
+LL |   /// ```
+   |  _____^
+LL | | /// /__________pkt->size___________/          /_result->size_/ /__pkt->size__/
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: /
+help: mark blocks that do not contain Rust code as text
+   |
+LL | /// ```text
+   |     ^^^^^^^
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:8:5
+   |
+LL |   /// ```
+   |  _____^
+LL | | ///    |
+LL | | /// LL | use foobar::Baz;
+LL | | ///    |     ^^^^^^ did you mean `baz::foobar`?
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: `
+help: mark blocks that do not contain Rust code as text
+   |
+LL | /// ```text
+   |     ^^^^^^^
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:19:5
+   |
+LL |   /// ```
+   |  _____^
+LL | | /// /_
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: /
+help: mark blocks that do not contain Rust code as text
+   |
+LL | /// ```text
+   |     ^^^^^^^
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:32:5
+   |
+LL |   /// ```rust
+   |  _____^
+LL | | /// /_
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: /
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:41:9
+   |
+LL |   ///     code with bad syntax
+   |  _________^
+LL | | ///     /_
+   | |__________^
+   |
+   = note: error from rustc: unknown start of token: /
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:55:9
+   |
+LL | ///     ```
+   |         ^^^
+   |
+   = note: error from rustc: unknown start of token: `
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:58:5
+   |
+LL |   /// ```edition2018
+   |  _____^
+LL | | /// /_
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: /
+
+warning: doc comment contains an invalid Rust code block
+  --> $DIR/invalid-syntax.rs:63:1
+   |
+LL | / #[doc = "```"]
+LL | | /// /_
+LL | | #[doc = "```"]
+   | |______________^
+   |
+   = help: mark blocks that do not contain Rust code as text: ```text
 
diff --git a/src/test/rustdoc/bad-codeblock-syntax.rs b/src/test/rustdoc/bad-codeblock-syntax.rs
new file mode 100644
index 00000000000..0ab2f68fcde
--- /dev/null
+++ b/src/test/rustdoc/bad-codeblock-syntax.rs
@@ -0,0 +1,27 @@
+// @has bad_codeblock_syntax/fn.foo.html
+// @has - '//*[@class="docblock"]/pre/code' '\_'
+/// ```
+/// \_
+/// ```
+pub fn foo() {}
+
+// @has bad_codeblock_syntax/fn.bar.html
+// @has - '//*[@class="docblock"]/pre/code' '`baz::foobar`'
+/// ```
+/// `baz::foobar`
+/// ```
+pub fn bar() {}
+
+// @has bad_codeblock_syntax/fn.quux.html
+// @has - '//*[@class="docblock"]/pre/code' '\_'
+/// ```rust
+/// \_
+/// ```
+pub fn quux() {}
+
+// @has bad_codeblock_syntax/fn.ok.html
+// @has - '//*[@class="docblock"]/pre/code[@class="language-text"]' '\_'
+/// ```text
+/// \_
+/// ```
+pub fn ok() {}