Variations on the dylibs/diamonds tests inspired by issue 82151.

These tests specifically show the effects of having both rlib and dylib library
variants present, as well as what happens when you mix in various settings for
`-C prefer-dynamic=...`.

Author: pnkfelix

src/test/ui/dylibs/auxiliary/a_basement_both.rs

@@ -0,0 +1,8 @@
+#![crate_name="a_basement"]
+#![crate_type="dylib"]
+#![crate_type="rlib"]
+
+// no-prefer-dynamic
+
+mod a_basement_core;
+pub use a_basement_core::*;

src/test/ui/dylibs/auxiliary/i_ground_both.rs

@@ -0,0 +1,10 @@
+#![crate_name="i_ground"]
+#![crate_type="dylib"]
+#![crate_type="rlib"]
+
+// no-prefer-dynamic
+
+pub extern crate a_basement as a;
+
+mod i_ground_core;
+pub use i_ground_core::*;

src/test/ui/dylibs/auxiliary/j_ground_both.rs

@@ -0,0 +1,10 @@
+#![crate_name="j_ground"]
+#![crate_type="dylib"]
+#![crate_type="rlib"]
+
+// no-prefer-dynamic
+
+pub extern crate a_basement as a;
+
+mod j_ground_core;
+pub use j_ground_core::*;

src/test/ui/dylibs/auxiliary/m_middle_both.rs

@@ -0,0 +1,11 @@
+#![crate_name="m_middle"]
+#![crate_type="dylib"]
+#![crate_type="rlib"]
+
+// no-prefer-dynamic
+
+pub extern crate i_ground as i;
+pub extern crate j_ground as j;
+
+mod m_middle_core;
+pub use m_middle_core::*;

src/test/ui/dylibs/auxiliary/s_upper_both.rs

@@ -0,0 +1,10 @@
+#![crate_name="s_upper"]
+#![crate_type="dylib"]
+#![crate_type="rlib"]
+
+// no-prefer-dynamic
+
+pub extern crate m_middle as m;
+
+mod s_upper_core;
+pub use s_upper_core::*;

src/test/ui/dylibs/auxiliary/t_upper_both.rs

@@ -0,0 +1,10 @@
+#![crate_name="t_upper"]
+#![crate_type="dylib"]
+#![crate_type="rlib"]
+
+// no-prefer-dynamic
+
+pub extern crate m_middle as m;
+
+mod t_upper_core;
+pub use t_upper_core::*;

src/test/ui/dylibs/auxiliary/z_roof_both.rs

@@ -0,0 +1,11 @@
+#![crate_name="z_roof"]
+#![crate_type="dylib"]
+#![crate_type="rlib"]
+
+// no-prefer-dynamic
+
+pub extern crate s_upper as s;
+pub extern crate t_upper as t;
+
+mod z_roof_core;
+pub use z_roof_core::*;

src/test/ui/dylibs/diamonds-b-prefdynstd.rs

@@ -0,0 +1,12 @@
+// run-pass
+
+// no-prefer-dynamic
+// compile-flags: -C prefer-dynamic=std -Z prefer-dynamic-std
+
+// aux-build: a_basement_both.rs
+
+pub extern crate a_basement as a;
+
+fn main() {
+    a::a();
+}

src/test/ui/dylibs/diamonds-b.rs

@@ -0,0 +1,14 @@
+// build-fail
+
+// The a_basement dependency has been compiled with `-C prefer-dynamic=no`,
+// which ends up leading to a duplication of `std` (and all crates underneath
+// it) in both the `a_basement` crate and in this crate. Rust does not support
+// having duplicate libraries like that, so this compilation will fail.
+
+// aux-build: a_basement_both.rs
+
+pub extern crate a_basement as a;
+
+fn main() {
+    a::a();
+}

src/test/ui/dylibs/diamonds-b.stderr

@@ -0,0 +1,74 @@
+error: cannot satisfy dependencies so `std` only shows up once (previously required dynamic, via [`diamonds_b`], and now also requires static, via [`a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `core` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `compiler_builtins` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `rustc_std_workspace_core` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `alloc` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `libc` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `unwind` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `cfg_if` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `hashbrown` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `rustc_std_workspace_alloc` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `rustc_demangle` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `std_detect` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `addr2line` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `gimli` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `object` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `miniz_oxide` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `adler` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: cannot satisfy dependencies so `panic_unwind` only shows up once (two static copies from multiple different locations, via [`std`, `a_basement`])
+   |
+   = help: having upstream crates all available in one format will likely make this go away
+
+error: aborting due to 18 previous errors
+

src/test/ui/dylibs/diamonds-bbbbbbb-prefdyn-z.rs

@@ -0,0 +1,23 @@
+// run-pass
+
+// Make use of new `-C prefer-dynamic=...` flag so only `z` is linked dynamically.
+
+// no-prefer-dynamic
+// compile-flags: -C prefer-dynamic=z_roof -Z prefer-dynamic-subset
+
+// aux-build: a_basement_both.rs
+// aux-build: i_ground_both.rs
+// aux-build: j_ground_both.rs
+// aux-build: m_middle_both.rs
+// aux-build: s_upper_both.rs
+// aux-build: t_upper_both.rs
+// aux-build: z_roof_both.rs
+
+extern crate z_roof as z;
+
+mod diamonds_core;
+
+fn main() {
+    diamonds_core::sanity_check();
+    diamonds_core::check_linked_function_equivalence();
+}

src/test/ui/dylibs/diamonds-bbbbbbb-prefdynstd.rs

@@ -0,0 +1,23 @@
+// run-pass
+
+// Make use of new `-C prefer-dynamic=...` flag to allow *only* `std` to be linked dynamically.
+
+// no-prefer-dynamic
+// compile-flags: -C prefer-dynamic=std -Z prefer-dynamic-std
+
+// aux-build: a_basement_both.rs
+// aux-build: i_ground_both.rs
+// aux-build: j_ground_both.rs
+// aux-build: m_middle_both.rs
+// aux-build: s_upper_both.rs
+// aux-build: t_upper_both.rs
+// aux-build: z_roof_both.rs
+
+extern crate z_roof as z;
+
+mod diamonds_core;
+
+fn main() {
+    diamonds_core::sanity_check();
+    diamonds_core::check_linked_function_equivalence();
+}

src/test/ui/dylibs/diamonds-d-prefdynstd.rs

@@ -0,0 +1,14 @@
+// run-pass
+
+// Make use of new `-C prefer-dynamic=...` flag to allow *only* `std` to be linked dynamically.
+
+// no-prefer-dynamic
+// compile-flags: -C prefer-dynamic=std -Z prefer-dynamic-std -la_basement
+
+// aux-build: a_basement_dynamic.rs
+
+extern crate a_basement as a;
+
+fn main() {
+    a::a();
+}

src/test/ui/dylibs/diamonds-ddddddd-prefdynstd.rs

@@ -0,0 +1,27 @@
+// run-pass
+
+// Make use of new `-C prefer-dynamic=...` flag to allow *only* `std` to be
+// linked dynamically via rustc's injected flags
+//
+// All the dependencies are dylibs, so we can successfully link them all and run them, *if* we
+// provide the right additional flags.
+
+// no-prefer-dynamic
+// compile-flags: -C prefer-dynamic=std -Z prefer-dynamic-std -la_basement -li_ground -lj_ground -lm_middle -ls_upper -lt_upper -lz_roof
+
+// aux-build: a_basement_dynamic.rs
+// aux-build: i_ground_dynamic.rs
+// aux-build: j_ground_dynamic.rs
+// aux-build: m_middle_dynamic.rs
+// aux-build: s_upper_dynamic.rs
+// aux-build: t_upper_dynamic.rs
+// aux-build: z_roof_dynamic.rs
+
+extern crate z_roof as z;
+
+mod diamonds_core;
+
+fn main() {
+    diamonds_core::sanity_check();
+    diamonds_core::check_linked_function_equivalence();
+}