Exclude/fix certain tests for swift-evolve (#21276)

* Add swift_evolve feature and disable several tests

This change adds a swift_evolve feature to our lit configuration and uses it to mark several tests as unsupported by swift_evolve.

One of these—test/api-digester/stability-stdlib-abi.swift—is actually pretty bad; we would really like to have it. But the digester has known issues exposed by swift-evolve.

* Remove order dependency in another test

* Tweaks from Jordan’s review

* Distinguish between tests which are intentionally unsupported and temporarily disabled.
* Add an explanation for one unsupproted test.
* Code nitpick.

Author: beccadax

test/SIL/Parser/array_roundtrip.swift

@@ -1,2 +1,7 @@
 // RUN: %target-swift-frontend %s -emit-sil -Ounchecked | %target-sil-opt -assume-parsing-unqualified-ownership-sil
+
+// Fails if the positions of the two Collection subscript requirements are
+// reversed. rdar://problem/46650834
+// XFAIL: swift_evolve
+
 var W = [UInt32](repeating: 0, count: 16)

test/SourceKit/DocSupport/doc_clang_module.swift

@@ -1,5 +1,8 @@
 // REQUIRES: objc_interop
 
+// SourceKit is expected to produce documentation in source order.
+// UNSUPPORTED: swift_evolve
+
 // FIXME: the test output we're comparing to is specific to macOS.
 // REQUIRES-ANY: OS=macosx
 

test/SourceKit/InterfaceGen/gen_stdlib.swift

@@ -8,17 +8,17 @@ var x: Int
 
 // Just check a small part, mainly to make sure we can print the interface of the stdlib.
 // CHECK-STDLIB-NOT: extension _SwiftNSOperatingSystemVersion
-// CHECK-STDLIB: struct Int : FixedWidthInteger, SignedInteger {
-// CHECK-STDLIB:   static var bitWidth: Int { get }
-// CHECK-STDLIB:   var nonzeroBitCount: Int { get }
+// CHECK-STDLIB-LABEL: struct Int : FixedWidthInteger, SignedInteger {
+// CHECK-STDLIB-DAG:   static var bitWidth: Int { get }
+// CHECK-STDLIB-DAG:   var nonzeroBitCount: Int { get }
 // CHECK-STDLIB: }
 
 // Check that extensions of nested decls are showing up.
 // CHECK-STDLIB-LABEL: extension String.Index {
-// CHECK-STDLIB: func samePosition(in utf8: String.UTF8View) -> String.UTF8View.Index?
-// CHECK-STDLIB: func samePosition(in characters: String) -> String.Index?
-// CHECK-STDLIB: func samePosition(in unicodeScalars: String.UnicodeScalarView) -> String.UnicodeScalarIndex?
-// CHECK-STDLIB-NEXT: }
+// CHECK-STDLIB-DAG: func samePosition(in utf8: String.UTF8View) -> String.UTF8View.Index?
+// CHECK-STDLIB-DAG: func samePosition(in characters: String) -> String.Index?
+// CHECK-STDLIB-DAG: func samePosition(in unicodeScalars: String.UnicodeScalarView) -> String.UnicodeScalarIndex?
+// CHECK-STDLIB: }
 
 // CHECK-MUTATING-ATTR: mutating func
 

test/api-digester/dump-module.swift

@@ -13,3 +13,8 @@
 // RUN: diff -u %S/Outputs/cake.json %t.dump.json
 // RUN: %api-digester -deserialize-sdk --input-paths %S/Outputs/cake-abi.json -o %t.dump.json
 // RUN: diff -u %S/Outputs/cake-abi.json %t.dump.json
+
+// The input JSON files need to be modified when standard library declarations
+// are reordered. This is expected behavior and we simply shouldn't run the test
+// when automatically evolving the standard library.
+// UNSUPPORTED: swift_evolve

test/api-digester/stability-stdlib-abi.swift

@@ -6,3 +6,9 @@
 // RUN: %clang -E -P -x c %S/Outputs/stability-stdlib-abi.swift.expected -o - | sed '/^\s*$/d' | sort > %t.tmp/stability-stdlib-abi.swift.expected
 // RUN: %clang -E -P -x c %t.tmp/changes.txt -o - | sed '/^\s*$/d' | sort > %t.tmp/changes.txt.tmp
 // RUN: diff -u %t.tmp/stability-stdlib-abi.swift.expected %t.tmp/changes.txt.tmp
+
+// The digester hasn't learned that we've stopped baking non-stored class member
+// order into the ABI. rdar://problem/46617463
+// The digester can incorrectly register a generic signature change when
+// declarations are shuffled. rdar://problem/46618883
+// XFAIL: swift_evolve

test/lit.cfg

@@ -540,6 +540,9 @@ elif swift_test_subset == 'only_stress':
 else:
     lit_config.fatal("Unknown test mode %r" % swift_test_subset)
 
+if 'swift_evolve' in lit_config.params:
+    config.available_features.add("swift_evolve")
+
 # Enable benchmark testing when the binary is found (has fully qualified path).
 if config.benchmark_o != 'Benchmark_O':
     config.available_features.add('benchmark')