Merge pull request #20625 from rudkx/designated-types-array

[ConstraintSystem] Add Array as a designated type for `+` and `+=`.

Author: rudkx

lib/Sema/CSSolver.cpp

@@ -1948,13 +1948,19 @@ Constraint *ConstraintSystem::selectDisjunction() {
   if (disjunctions.empty())
     return nullptr;
 
-  if (auto *disjunction = selectBestBindingDisjunction(*this, disjunctions))
-    return disjunction;
-
+  // Attempt apply disjunctions first. When we have operators with
+  // designated types, this is important, because it allows us to
+  // select all the preferred operator overloads prior to other
+  // disjunctions that we may not be able to short-circuit, allowing
+  // us to eliminate behavior that is exponential in the number of
+  // operators in the expression.
   if (getASTContext().isSwiftVersionAtLeast(5))
     if (auto *disjunction = selectApplyDisjunction())
       return disjunction;
 
+  if (auto *disjunction = selectBestBindingDisjunction(*this, disjunctions))
+    return disjunction;
+
   // Pick the disjunction with the smallest number of active choices.
   auto minDisjunction =
       std::min_element(disjunctions.begin(), disjunctions.end(),

stdlib/public/core/Array.swift

@@ -1290,6 +1290,25 @@ extension Array: RangeReplaceableCollection {
   }
 }
 
+// Implementations of + and += for same-type arrays. This combined
+// with the operator declarations for these operators designating this
+// type as a place to prefer this operator help the expression type
+// checker speed up cases where there is a large number of uses of the
+// operator in the same expression.
+extension Array {
+  @inlinable
+  public static func + (lhs: Array, rhs: Array) -> Array {
+    var lhs = lhs
+    lhs.append(contentsOf: rhs)
+    return lhs
+  }
+
+  @inlinable
+  public static func += (lhs: inout Array, rhs: Array) {
+    lhs.append(contentsOf: rhs)
+  }
+}
+
 extension Array: CustomReflectable {
   /// A mirror that reflects the array.
   public var customMirror: Mirror {

stdlib/public/core/Policy.swift

@@ -420,7 +420,7 @@ infix operator   & : MultiplicationPrecedence, BinaryInteger
 
 // "Additive"
 
-infix operator   + : AdditionPrecedence, AdditiveArithmetic, String, Strideable
+infix operator   + : AdditionPrecedence, AdditiveArithmetic, String, Array, Strideable
 infix operator  &+ : AdditionPrecedence, FixedWidthInteger
 infix operator   - : AdditionPrecedence, AdditiveArithmetic, Strideable
 infix operator  &- : AdditionPrecedence, FixedWidthInteger
@@ -474,7 +474,7 @@ infix operator   *= : AssignmentPrecedence, Numeric
 infix operator  &*= : AssignmentPrecedence, FixedWidthInteger
 infix operator   /= : AssignmentPrecedence, BinaryInteger
 infix operator   %= : AssignmentPrecedence, BinaryInteger
-infix operator   += : AssignmentPrecedence, AdditiveArithmetic, String, Strideable
+infix operator   += : AssignmentPrecedence, AdditiveArithmetic, String, Array, Strideable
 infix operator  &+= : AssignmentPrecedence, FixedWidthInteger
 infix operator   -= : AssignmentPrecedence, AdditiveArithmetic, Strideable
 infix operator  &-= : AssignmentPrecedence, FixedWidthInteger

test/Constraints/bridging.swift

@@ -269,7 +269,7 @@ func rdar19831698() {
   var v72 = true + true // expected-error{{binary operator '+' cannot be applied to two 'Bool' operands}}
   // expected-note @-1 {{overloads for '+' exist with these partially matching parameter lists:}}
   var v73 = true + [] // expected-error{{binary operator '+' cannot be applied to operands of type 'Bool' and '[Any]'}}
-  // expected-note @-1 {{overloads for '+' exist with these partially matching parameter lists: (Self, Other), (Other, Self)}}
+  // expected-note @-1 {{overloads for '+' exist with these partially matching parameter lists: (Array<Element>, Array<Element>), (Self, Other), (Other, Self)}}
   var v75 = true + "str" // expected-error {{binary operator '+' cannot be applied to operands of type 'Bool' and 'String'}} expected-note {{expected an argument list of type '(String, String)'}}
 }
 

test/Misc/misc_diagnostics.swift

@@ -103,11 +103,14 @@ func test17875634() {
   var col = 2
   var coord = (row, col)
 
-  match += (1, 2) // expected-error{{argument type '(Int, Int)' does not conform to expected type 'Sequence'}}
+  match += (1, 2) // expected-error{{binary operator '+=' cannot be applied to operands of type '[(Int, Int)]' and '(Int, Int)'}}
+  // expected-note@-1 {{overloads for '+=' exist with these partially matching parameter lists: (inout Array<Element>, Array<Element>), (inout Self, Other)}}
 
-  match += (row, col) // expected-error{{argument type '(@lvalue Int, @lvalue Int)' does not conform to expected type 'Sequence'}}
+  match += (row, col) // expected-error{{binary operator '+=' cannot be applied to operands of type '[(Int, Int)]' and '(Int, Int)}}
+  // expected-note@-1 {{overloads for '+=' exist with these partially matching parameter lists: (inout Array<Element>, Array<Element>), (inout Self, Other)}}
 
-  match += coord // expected-error{{argument type '@lvalue (Int, Int)' does not conform to expected type 'Sequence'}}
+  match += coord // expected-error{{binary operator '+=' cannot be applied to operands of type '[(Int, Int)]' and '(Int, Int)'}}
+  // expected-note@-1 {{overloads for '+=' exist with these partially matching parameter lists: (inout Array<Element>, Array<Element>), (inout Self, Other)}}
 
   match.append(row, col) // expected-error {{instance method 'append' expects a single parameter of type '(Int, Int)'}} {{16-16=(}} {{24-24=)}}
 

validation-test/Sema/type_checker_perf/fast/rdar18360240.swift.gyb

@@ -1,4 +1,4 @@
-// RUN: %scale-test --begin 2 --end 10 --step 2 --select NumConstraintScopes --polynomial-threshold 1.5 %s
+// RUN: %scale-test --begin 2 --end 10 --step 2 --select NumConstraintScopes --polynomial-threshold 1.5 %s -Xfrontend=-swift-version -Xfrontend=5 -Xfrontend=-solver-disable-shrink -Xfrontend=-disable-constraint-solver-performance-hacks -Xfrontend=-solver-enable-operator-designated-types
 // REQUIRES: OS=macosx
 // REQUIRES: asserts
 

validation-test/Sema/type_checker_perf/slow/rdar23429943.swift renamed to validation-test/Sema/type_checker_perf/fast/rdar23429943.swift

@@ -1,7 +1,6 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1 -swift-version 5 -solver-disable-shrink -disable-constraint-solver-performance-hacks -solver-enable-operator-designated-types
 // REQUIRES: tools-release,no_asserts
 
 let _ = [0].reduce([Int]()) {
-  // expected-error@-1 {{reasonable time}}
   return $0.count == 0 && ($1 == 0 || $1 == 2 || $1 == 3) ? [] : $0 + [$1]
 }

validation-test/Sema/type_checker_perf/fast/rdar25866240.swift.gyb

@@ -1,4 +1,4 @@
-// RUN: %scale-test --begin 2 --end 10 --step 1 --select NumConstraintScopes %s
+// RUN: %scale-test --begin 2 --end 10 --step 1 --select NumConstraintScopes %s -Xfrontend=-swift-version -Xfrontend=5 -Xfrontend=-solver-disable-shrink -Xfrontend=-disable-constraint-solver-performance-hacks -Xfrontend=-solver-enable-operator-designated-types
 // REQUIRES: OS=macosx
 // REQUIRES: asserts