add build-fail test for simd type with an element type that's a wide pointer

Author: programmerjake

src/test/ui/simd/simd-type-generic-monomorphisation-wide-ptr.rs

@@ -0,0 +1,12 @@
+// build-fail
+
+#![feature(repr_simd)]
+
+// error-pattern:monomorphising SIMD type `S<[*mut [u8]; 4]>` with a non-primitive-scalar (integer/float/pointer) element type `*mut [u8]`
+
+#[repr(simd)]
+struct S<T>(T);
+
+fn main() {
+    let _v: Option<S<[*mut [u8]; 4]>> = None;
+}

src/test/ui/simd/simd-type-generic-monomorphisation-wide-ptr.stderr

@@ -0,0 +1,4 @@
+error: monomorphising SIMD type `S<[*mut [u8]; 4]>` with a non-primitive-scalar (integer/float/pointer) element type `*mut [u8]`
+
+error: aborting due to previous error
+