Merge pull request #60137 from xedin/rdar-97261826

[CSApply] Use fully qualified locator while coercing member chain result

Author: xedin

lib/Sema/CSApply.cpp

@@ -3466,7 +3466,10 @@ namespace {
       // type.
       auto *subExpr = expr->getSubExpr();
       auto type = simplifyType(cs.getType(expr));
-      subExpr = coerceToType(subExpr, type, cs.getConstraintLocator(subExpr));
+      subExpr = coerceToType(
+          subExpr, type,
+          cs.getConstraintLocator(
+              expr, ConstraintLocator::UnresolvedMemberChainResult));
       cs.setType(subExpr, type);
       return subExpr;
     }

test/Constraints/implicit_double_cgfloat_conversion.swift

@@ -262,3 +262,21 @@ func assignments_with_and_without_optionals() {
     copy.prop = (true ? cgf : (false ? v : cgf))
   }
 }
+
+extension CGFloat {
+  static let `default` = 42.0
+}
+
+// rdar://97261826 - crash during constraint application with leading-dot syntax
+func assignment_with_leading_dot_syntax() {
+  class Container {
+    var prop: CGFloat = 0
+  }
+
+  struct Test {
+    let test: Void = {
+      let c = Container()
+      c.prop = .default // Ok (Double -> CGFloat)
+    }()
+  }
+}