Merge pull request #18285 from dingobye/sr8385

[Sema] Avoid merging type variables that can have different results in CS.

Author: xedin

lib/Sema/CSGen.cpp

@@ -318,6 +318,13 @@ namespace {
         return { false, expr };
       }
 
+      // Don't walk into unresolved member expressions - we avoid merging type
+      // variables inside UnresolvedMemberExpr and those outside, since they
+      // should be allowed to behave independently in CS.
+      if (isa<UnresolvedMemberExpr>(expr)) {
+        return {false, expr };
+      }
+
       return { true, expr };
     }
 

test/Constraints/array_literal.swift

@@ -340,3 +340,19 @@ func testConditional(i: Int, s: String) {
   let _: PArray<Int> = [i, i, i]
   let _: PArray<String> = [s, s, s] // expected-error{{cannot convert value of type '[String]' to specified type 'PArray<String>'}}
 }
+
+
+// SR-8385
+enum SR8385: ExpressibleByStringLiteral {
+  case text(String)
+  init(stringLiteral value: String) {
+    self = .text(value)
+  }
+}
+
+func testSR8385() {
+  let _: [SR8385] = [SR8385("hello")]
+  let _: [SR8385] = [.text("hello")]
+  let _: [SR8385] = ["hello", SR8385.text("world")]
+  let _: [SR8385] = ["hello", .text("world")]
+}