---

yaml
---
r: 340476
b: refs/heads/rxwei-patch-1
c: 26d0324
h: refs/heads/master

Author: xedin

[refs]

@@ -1015,7 +1015,7 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2018-08-18-a: b10b1fce14385faa6d44f6b933e95
 refs/heads/rdar-43033749-fix-batch-mode-no-diags-swift-5.0-branch: a14e64eaad30de89f0f5f0b2a782eed7ecdcb255
 refs/heads/revert-19006-error-bridging-integer-type: 8a9065a3696535305ea53fe9b71f91cbe6702019
 refs/heads/revert-19050-revert-19006-error-bridging-integer-type: ecf752d54b05dd0a20f510f0bfa54a3fec3bcaca
-refs/heads/rxwei-patch-1: 59bc60eb201e35a2cf90a5a286c78d97500f8111
+refs/heads/rxwei-patch-1: 26d03243183ced04454667496eb2df37e2556670
 refs/heads/shahmishal-patch-1: e58ec0f7488258d42bef51bc3e6d7b3dc74d7b2a
 refs/heads/typelist-existential: 4046359efd541fb5c72d69a92eefc0a784df8f5e
 refs/tags/swift-4.2-DEVELOPMENT-SNAPSHOT-2018-08-20-a: 4319ba09e4fb8650ee86061075c74a016b6baab9

branches/rxwei-patch-1/lib/Sema/CSApply.cpp

@@ -3897,6 +3897,19 @@ namespace {
       simplifyExprType(E);
       auto valueType = cs.getType(E);
 
+      // TODO(diagnostics): Once all of the diagnostics are moved to
+      // new diagnostics framework this check could be eliminated.
+      //
+      // Only way for this to happen is CSDiag try to re-typecheck
+      // sub-expression which contains this placeholder with
+      // `AllowUnresolvedTypeVariables` flag set.
+      //
+      // A better solution could be to replace placeholders with this
+      // implicit call early on and type-check that call together with
+      // the rest of the constraint system.
+      if (valueType->hasUnresolvedType())
+        return nullptr;
+
       auto &tc = cs.getTypeChecker();
       auto &ctx = tc.Context;
       // Synthesize a call to _undefined() of appropriate type.

branches/rxwei-patch-1/validation-test/compiler_crashers_2_fixed/0196-rdar48937223.swift

@@ -0,0 +1,11 @@
+// RUN: %target-typecheck-verify-swift
+
+protocol P {}
+
+func fn<T, U: P>(_ arg1: T, arg2: (T) -> U) {}
+
+func test(str: String) {
+  fn(str) { arg in
+    <#FOO#> // expected-error {{editor placeholder in source file}}
+  }
+}