Add extended error message for E0523

Adds the extended error documentation for E0523 to indicate that the
error is no longer produced by the compiler.

Update the E0464 documentation to include example code that produces the
error.

Remove the error message E0523 from the compiler and replace it with an
internal compiler error.

2 files changed, 27 insertions, 0 deletions

diff --git a/tests/ui/error-codes/E0523.rs b/tests/ui/error-codes/E0523.rs
new file mode 100644
index 00000000000..47717fbd508
--- /dev/null
+++ b/tests/ui/error-codes/E0523.rs
@@ -0,0 +1,14 @@
+// aux-build:crateresolve1-1.rs
+// aux-build:crateresolve1-2.rs
+// aux-build:crateresolve1-3.rs
+
+// normalize-stderr-test: "\.nll/" -> "/"
+// normalize-stderr-test: "\\\?\\" -> ""
+// normalize-stderr-test: "(lib)?crateresolve1-([123])\.[a-z]+" -> "libcrateresolve1-$2.somelib"
+
+// NOTE: This test is duplicated from `tests/ui/crate-loading/crateresolve1.rs`.
+
+extern crate crateresolve1;
+//~^ ERROR multiple candidates for `rlib` dependency `crateresolve1` found
+
+fn main() {}
diff --git a/tests/ui/error-codes/E0523.stderr b/tests/ui/error-codes/E0523.stderr
new file mode 100644
index 00000000000..8e3eb2159c2
--- /dev/null
+++ b/tests/ui/error-codes/E0523.stderr
@@ -0,0 +1,13 @@
+error[E0464]: multiple candidates for `rlib` dependency `crateresolve1` found
+  --> $DIR/E0523.rs:11:1
+   |
+LL | extern crate crateresolve1;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: candidate #1: $TEST_BUILD_DIR/error-codes/E0523/auxiliary/libcrateresolve1-1.somelib
+   = note: candidate #2: $TEST_BUILD_DIR/error-codes/E0523/auxiliary/libcrateresolve1-2.somelib
+   = note: candidate #3: $TEST_BUILD_DIR/error-codes/E0523/auxiliary/libcrateresolve1-3.somelib
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0464`.