[CSSimplify] Adjusting logic on simplifyOptionalObjectConstraint to attempt InsertCall fix before remove unwrap

Author: LucianoPAlmeida

lib/Sema/CSDiagnostics.h

@@ -498,7 +498,7 @@ class MemberAccessOnOptionalBaseFailure final : public FailureDiagnostic {
   }
 
   SourceLoc getLoc() const override {
-    // The end location points the dot in the member access.
+    // The end location points to the dot in the member access.
     return getSourceRange().End;
   }
 

lib/Sema/CSSimplify.cpp

@@ -5697,41 +5697,39 @@ ConstraintSystem::simplifyOptionalObjectConstraint(
   // If the base type is not optional, let's attempt a fix (if possible)
   // and assume that `!` is just not there.
   if (!objectTy) {
+    if (!shouldAttemptFixes())
+      return SolutionKind::Error;
+    
     // Let's see if we can apply a specific fix here.
-    if (shouldAttemptFixes()) {
-      if (optTy->isHole())
-        return SolutionKind::Solved;
+    if (optTy->isHole())
+      return SolutionKind::Solved;
+    
+    auto fnType = optTy->getAs<FunctionType>();
+    if (fnType && fnType->getNumParams() == 0) {
+      // For function types with no parameters, let's try to
+      // offer a "make it a call" fix if possible.
+      auto optionalResultType = fnType->getResult()->getOptionalObjectType();
+      if (optionalResultType) {
+        if (matchTypes(optionalResultType, second, ConstraintKind::Bind,
+                       flags | TMF_ApplyingFix, locator)
+                .isSuccess()) {
+          auto *fix =
+              InsertExplicitCall::create(*this, getConstraintLocator(locator));
+
+          return recordFix(fix) ? SolutionKind::Error : SolutionKind::Solved;
+        }
+      }
+    }
 
-      auto *fix =
-          RemoveUnwrap::create(*this, optTy, getConstraintLocator(locator));
+    auto *fix =
+        RemoveUnwrap::create(*this, optTy, getConstraintLocator(locator));
 
-      if (recordFix(fix))
-        return SolutionKind::Error;
-
-      // If the fix was successful let's record
-      // "fixed" object type and continue.
-      objectTy = optTy;
-    } else {
-      // If fixes are not allowed, no choice but to fail.
+    if (recordFix(fix))
       return SolutionKind::Error;
-    }
-  }
 
-  auto fnType = optTy->getAs<FunctionType>();
-  if (shouldAttemptFixes() && fnType && fnType->getNumParams() == 0) {
-    // For function types with no parameters, let's try to
-    // offer a "make it a call" fix if possible.
-    auto optionalResultType = fnType->getResult()->getOptionalObjectType();
-    if (optionalResultType) {
-      if (matchTypes(optionalResultType, second, ConstraintKind::Bind,
-                     flags | TMF_ApplyingFix, locator)
-              .isSuccess()) {
-        auto *fix =
-            InsertExplicitCall::create(*this, getConstraintLocator(locator));
-
-        return recordFix(fix) ? SolutionKind::Error : SolutionKind::Solved;
-      }
-    }
+    // If the fix was successful let's record
+    // "fixed" object type and continue.
+    objectTy = optTy;
   }
 
   // The object type is an lvalue if the optional was.

test/Constraints/diagnostics.swift

@@ -1342,3 +1342,10 @@ func rdar62989214() {
     arr[flag].isTrue // expected-error {{cannot convert value of type 'Flag' to expected argument type 'Int'}}
   }
 }
+
+// SR-5688
+func SR5688_1() -> String? { "" }
+SR5688_1!.count // expected-error {{function 'SR5688_1' was used as a property; add () to call it}} {{9-9=()}}
+
+func SR5688_2() -> Int? { 0 }
+let _: Int = SR5688_2! // expected-error {{function 'SR5688_2' was used as a property; add () to call it}} {{22-22=()}}

test/Constraints/fixes.swift

@@ -110,8 +110,7 @@ class T {
     func m1() {
       // <rdar://problem/17741575>
       let l = self.m2!.prop1
-      // expected-error@-1 {{cannot force unwrap value of non-optional type '() -> U?'}} {{22-23=}}
-      // expected-error@-2 {{method 'm2' was used as a property; add () to call it}}  {{22-22=()}}
+      // expected-error@-1 {{method 'm2' was used as a property; add () to call it}}  {{22-22=()}}
     }
 
     func m2() -> U! {