docs/test: add UI test and long-form error docs for E0462

compiler/rustc_error_codes/src/error_codes.rs

@@ -244,6 +244,7 @@ E0457: include_str!("./error_codes/E0457.md"),
 E0458: include_str!("./error_codes/E0458.md"),
 E0459: include_str!("./error_codes/E0459.md"),
 E0460: include_str!("./error_codes/E0460.md"),
+E0462: include_str!("./error_codes/E0462.md"),
 E0463: include_str!("./error_codes/E0463.md"),
 E0464: include_str!("./error_codes/E0464.md"),
 E0466: include_str!("./error_codes/E0466.md"),
@@ -594,7 +595,6 @@ E0791: include_str!("./error_codes/E0791.md"),
 //  E0427, // merged into 530
 //  E0456, // plugin `..` is not available for triple `..`
     E0461, // couldn't find crate `..` with expected target triple ..
-    E0462, // found staticlib `..` instead of rlib or dylib
     E0465, // multiple .. candidates for `..` found
 //  E0467, // removed
 //  E0470, // removed

compiler/rustc_error_codes/src/error_codes/E0462.md

@@ -0,0 +1,32 @@
+Found `staticlib` `..` instead of `rlib` or `dylib`.
+
+Consider the following two files:
+
+`a.rs`
+```ignore (cannot-link-with-other-tests)
+#![crate_type = "staticlib"]
+
+fn foo() {}
+```
+
+`main.rs`
+```ignore (cannot-link-with-other-tests)
+extern crate a;
+
+fn main() {
+    a::foo();
+}
+```
+
+Crate `a` is compiled as a `staticlib`. A `staticlib` is a system-dependant
+library only intended for linking with non-Rust applications (C programs). Note
+that `staticlib`s include all upstream dependencies (`core`, `std`, other user
+dependencies, etc) which makes them significantly larger than `dylib`s:
+prefer `staticlib` for linking with C programs. Learn more about different
+`crate_type`s in [this section of the Reference](../reference/linkage.html).
+
+This error can be fixed by:
+ * Using [Cargo](../cargo/index.html), the Rust package manager, automatically
+   fixing this issue.
+ * Recompiling the crate as a `rlib` or `dylib`; formats suitable for Rust
+   linking.

src/test/ui/error-codes/E0462.rs

@@ -0,0 +1,11 @@
+// aux-build:found-staticlib.rs
+
+// normalize-stderr-test: "\.nll/" -> "/"
+// normalize-stderr-test: "\\\?\\" -> ""
+// normalize-stderr-test: "(lib)?found_staticlib\.[a-z]+" -> "libfound_staticlib.somelib"
+
+extern crate found_staticlib; //~ ERROR E0462
+
+fn main() {
+    found_staticlib::foo();
+}

src/test/ui/error-codes/E0462.stderr

@@ -0,0 +1,13 @@
+error[E0462]: found staticlib `found_staticlib` instead of rlib or dylib
+  --> $DIR/E0462.rs:7:1
+   |
+LL | extern crate found_staticlib;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the following crate versions were found:
+           crate `found_staticlib`: $TEST_BUILD_DIR/error-codes/E0462/auxiliary/libfound_staticlib.somelib
+   = help: please recompile that crate using --crate-type lib
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0462`.

src/test/ui/error-codes/auxiliary/found-staticlib.rs

@@ -0,0 +1,4 @@
+// no-prefer-dynamic
+#![crate_type = "staticlib"]
+
+pub fn foo() {}

src/tools/tidy/src/error_codes_check.rs

@@ -11,8 +11,8 @@ use regex::Regex;
 
 // A few of those error codes can't be tested but all the others can and *should* be tested!
 const EXEMPTED_FROM_TEST: &[&str] = &[
-    "E0313", "E0461", "E0462", "E0465", "E0476", "E0490", "E0514", "E0519", "E0523", "E0554",
-    "E0640", "E0717", "E0729", "E0789",
+    "E0313", "E0461", "E0465", "E0476", "E0490", "E0514", "E0519", "E0523", "E0554", "E0640",
+    "E0717", "E0729", "E0789",
 ];
 
 // Some error codes don't have any tests apparently...