Merge pull request #38631 from hamishknight/theres-precedence-for-this

Author: hamishknight

lib/Sema/CSApply.cpp

@@ -7891,6 +7891,15 @@ static std::pair<Expr *, unsigned> getPrecedenceParentAndIndex(Expr *expr,
   }
   Expr *parent = it->second;
 
+  // Look through an unresolved chain wrapper expr, as it has no effect on
+  // precedence.
+  if (isa<UnresolvedMemberChainResultExpr>(parent)) {
+    it = parentMap.find(parent);
+    if (it == parentMap.end())
+      return {nullptr, 0};
+    parent = it->second;
+  }
+
   // Handle all cases where the answer isn't just going to be { parent, 0 }.
   if (auto tuple = dyn_cast<TupleExpr>(parent)) {
     // Get index of expression in tuple.
@@ -7970,13 +7979,13 @@ bool swift::exprNeedsParensOutsideFollowingOperator(
   Expr *parent;
   unsigned index;
   std::tie(parent, index) = getPrecedenceParentAndIndex(expr, rootExpr);
-  if (!parent || isa<TupleExpr>(parent)) {
+  if (!parent)
     return false;
-  }
 
-  if (auto parenExp = dyn_cast<ParenExpr>(parent))
-    if (!parenExp->isImplicit())
+  if (isa<ParenExpr>(parent) || isa<TupleExpr>(parent)) {
+    if (!parent->isImplicit())
       return false;
+  }
 
   if (parent->isInfixOperator()) {
     auto parentPG = TypeChecker::lookupPrecedenceGroupForInfixOperator(DC,

lib/Sema/CSDiagnostics.cpp

@@ -1146,6 +1146,7 @@ ASTNode MissingExplicitConversionFailure::getAnchor() const {
 bool MissingExplicitConversionFailure::diagnoseAsError() {
   auto *DC = getDC();
   auto *anchor = castToExpr(getAnchor());
+  auto *rawAnchor = castToExpr(getRawAnchor());
 
   auto fromType = getFromType();
   auto toType = getToType();
@@ -1171,7 +1172,7 @@ bool MissingExplicitConversionFailure::diagnoseAsError() {
   }
 
   bool needsParensInside = exprNeedsParensBeforeAddingAs(anchor);
-  bool needsParensOutside = exprNeedsParensAfterAddingAs(anchor, expr);
+  bool needsParensOutside = exprNeedsParensAfterAddingAs(anchor, rawAnchor);
 
   llvm::SmallString<2> insertBefore;
   llvm::SmallString<32> insertAfter;
@@ -1310,11 +1311,8 @@ void MissingOptionalUnwrapFailure::offerDefaultValueUnwrapFixIt(
   // Figure out what we need to parenthesize.
   bool needsParensInside =
       exprNeedsParensBeforeAddingNilCoalescing(DC, const_cast<Expr *>(expr));
-  auto parentExpr = findParentExpr(anchor);
-  if (parentExpr && isa<UnresolvedMemberChainResultExpr>(parentExpr))
-    parentExpr = findParentExpr(parentExpr);
   bool needsParensOutside = exprNeedsParensAfterAddingNilCoalescing(
-      DC, const_cast<Expr *>(expr), parentExpr);
+      DC, const_cast<Expr *>(expr), castToExpr(getRawAnchor()));
 
   llvm::SmallString<2> insertBefore;
   llvm::SmallString<32> insertAfter;

test/Constraints/bridging.swift

@@ -258,9 +258,9 @@ func rdar19770981(_ s: String, ns: NSString) {
   _ = ns as String > s
 
   // 'as' has lower precedence than '+' so add parens with the fixit:
-  s + ns // expected-error{{'NSString' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?}}{{9-9= as String}}
+  s + ns // expected-error{{'NSString' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?}} {{7-7=(}} {{9-9= as String)}}
   _ = s + (ns as String)
-  ns + s // expected-error{{'NSString' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?}}{{5-5= as String}}
+  ns + s // expected-error{{'NSString' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?}} {{3-3=(}} {{5-5= as String)}}
   _ = (ns as String) + s
 }
 

test/Constraints/diagnostics.swift

@@ -1415,3 +1415,31 @@ func rdar74696023() {
     // expected-note@-2 {{force-unwrap using '!' to abort execution if the optional value contains 'nil'}}
   }
 }
+
+func testUnwrapFixIts(x: Int?) {
+  let _ = x + 2 // expected-error {{value of optional type 'Int?' must be unwrapped to a value of type 'Int'}}
+  // expected-note@-1 {{coalesce using '??' to provide a default when the optional value contains 'nil'}} {{11-11=(}} {{12-12= ?? <#default value#>)}}
+  // expected-note@-2 {{force-unwrap using '!' to abort execution if the optional value contains 'nil'}} {{12-12=!}}
+  let _ = (x ?? 0) + 2
+
+  let _ = 2 + x // expected-error {{value of optional type 'Int?' must be unwrapped to a value of type 'Int'}}
+  // expected-note@-1 {{coalesce using '??' to provide a default when the optional value contains 'nil'}} {{15-15=(}} {{16-16= ?? <#default value#>)}}
+  // expected-note@-2 {{force-unwrap using '!' to abort execution if the optional value contains 'nil'}} {{16-16=!}}
+  let _ = 2 + (x ?? 0)
+
+  func foo(y: Int) {}
+  foo(y: x) // expected-error {{value of optional type 'Int?' must be unwrapped to a value of type 'Int'}}
+  // expected-note@-1 {{coalesce using '??' to provide a default when the optional value contains 'nil'}} {{11-11= ?? <#default value#>}}
+  // expected-note@-2 {{force-unwrap using '!' to abort execution if the optional value contains 'nil'}} {{11-11=!}}
+  foo(y: x ?? 0) 
+
+  let _ = x < 2 // expected-error {{value of optional type 'Int?' must be unwrapped to a value of type 'Int'}}
+  // expected-note@-1 {{coalesce using '??' to provide a default when the optional value contains 'nil'}} {{12-12= ?? <#default value#>}}
+  // expected-note@-2 {{force-unwrap using '!' to abort execution if the optional value contains 'nil'}} {{12-12=!}}
+  let _ = x ?? 0 < 2
+
+  let _ = 2 < x // expected-error {{value of optional type 'Int?' must be unwrapped to a value of type 'Int'}}
+  // expected-note@-1 {{coalesce using '??' to provide a default when the optional value contains 'nil'}} {{16-16= ?? <#default value#>}}
+  // expected-note@-2 {{force-unwrap using '!' to abort execution if the optional value contains 'nil'}} {{16-16=!}}
+  let _ = 2 < x ?? 0
+}