[TypeChecker] Don't double validate dict types

Prior, binding generic args in dictionary type checking would double
resolve the key and value types a second time, emitting duplicated
errors potentially. Instead, we reuse the resolved types.

Author: milseman

lib/Sema/TypeCheckType.cpp

@@ -2437,6 +2437,8 @@ Type TypeResolver::resolveDictionaryType(DictionaryTypeRepr *repr,
     // Check the requirements on the generic arguments.
     auto unboundTy = dictDecl->getDeclaredType();
     TypeLoc args[2] = { TypeLoc(repr->getKey()), TypeLoc(repr->getValue()) };
+    args[0].setType(keyTy, true);
+    args[1].setType(valueTy, true);
 
     if (!TC.applyUnboundGenericArguments(
             unboundTy, dictDecl, repr->getStartLoc(), DC, args,

test/attr/attr_escaping.swift

@@ -89,7 +89,6 @@ func misuseEscaping(_ a: (@escaping (Int) -> Int, Int)) {} // expected-error{{@e
 func misuseEscaping(_ a: [@escaping (Int) -> Int]) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{27-37=}}
 func misuseEscaping(_ a: [@escaping (Int) -> Int]?) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{27-37=}}
 func misuseEscaping(_ a: [Int : @escaping (Int) -> Int]) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{33-43=}}
-  // expected-error@-1{{@escaping attribute may only be used in function parameter position}} {{33-43=}}
 func misuseEscaping(_ a: GenericStruct<@escaping (Int) -> Int>) {} // expected-error{{@escaping attribute may only be used in function parameter position}} {{40-50=}}
 
 func takesEscapingGeneric<T>(_ fn: @escaping () -> T) {}