[ConstraintSystem] Add TypeLoc caching to constraint system

This is useful for explicit casts and type expressions, where
type loc and expression types might be different, and allows
constraint solver to avoid setting opened types to expressions
which resolves multiple crashes.

Author: xedin

lib/Sema/CSApply.cpp

@@ -2458,10 +2458,9 @@ namespace {
     }
 
     Expr *visitTypeExpr(TypeExpr *expr) {
-      auto toType = simplifyType(expr->getTypeLoc().getType());
+      auto toType = simplifyType(cs.getType(expr->getTypeLoc()));
       expr->getTypeLoc().setType(toType, /*validated=*/true);
       cs.setType(expr, MetatypeType::get(toType));
-      
       return expr;
     }
 
@@ -3121,7 +3120,7 @@ namespace {
     Expr *visitIsExpr(IsExpr *expr) {
       // Turn the subexpression into an rvalue.
       auto &tc = cs.getTypeChecker();
-      auto toType = simplifyType(expr->getCastTypeLoc().getType());
+      auto toType = simplifyType(cs.getType(expr->getCastTypeLoc()));
       auto sub = cs.coerceToRValue(expr->getSubExpr());
 
       checkForImportedUsedConformances(toType);
@@ -3193,6 +3192,7 @@ namespace {
                                sub, expr->getLoc(), SourceLoc(),
                                TypeLoc::withoutLoc(toType));
         cs.setType(cast, toOptType);
+        cs.setType(cast->getCastTypeLoc(), toType);
         if (expr->isImplicit())
           cast->setImplicit();
 
@@ -3470,7 +3470,7 @@ namespace {
 
     Expr *visitCoerceExpr(CoerceExpr *expr, Optional<unsigned> choice) {
       // Simplify the type we're casting to.
-      auto toType = simplifyType(expr->getCastTypeLoc().getType());
+      auto toType = simplifyType(cs.getType(expr->getCastTypeLoc()));
       expr->getCastTypeLoc().setType(toType, /*validated=*/true);
       checkForImportedUsedConformances(toType);
 
@@ -3556,7 +3556,7 @@ namespace {
     // Most of the logic for dealing with ForcedCheckedCastExpr.
     Expr *handleForcedCheckedCastExpr(ForcedCheckedCastExpr *expr) {
       // Simplify the type we're casting to.
-      auto toType = simplifyType(expr->getCastTypeLoc().getType());
+      auto toType = simplifyType(cs.getType(expr->getCastTypeLoc()));
       expr->getCastTypeLoc().setType(toType, /*validated=*/true);
       checkForImportedUsedConformances(toType);
 
@@ -3599,6 +3599,7 @@ namespace {
         auto *result = new (tc.Context) CoerceExpr(sub, expr->getLoc(),
                                                    expr->getCastTypeLoc());
         cs.setType(result, toType);
+        cs.setType(result->getCastTypeLoc(), toType);
         unsigned disjunctionChoice =
           (castKind == CheckedCastKind::Coercion ? 0 : 1);
         return visitCoerceExpr(result, disjunctionChoice);
@@ -3636,7 +3637,7 @@ namespace {
     Expr *handleConditionalCheckedCastExpr(ConditionalCheckedCastExpr *expr,
                                            bool isInsideIsExpr = false) {
       // Simplify the type we're casting to.
-      auto toType = simplifyType(expr->getCastTypeLoc().getType());
+      auto toType = simplifyType(cs.getType(expr->getCastTypeLoc()));
       checkForImportedUsedConformances(toType);
       expr->getCastTypeLoc().setType(toType, /*validated=*/true);
 
@@ -3674,6 +3675,7 @@ namespace {
         auto *coerce = new (tc.Context) CoerceExpr(sub, expr->getLoc(),
                                                    expr->getCastTypeLoc());
         cs.setType(coerce, toType);
+        cs.setType(coerce->getCastTypeLoc(), toType);
         unsigned disjunctionChoice =
           (castKind == CheckedCastKind::Coercion ? 0 : 1);
         Expr *result = visitCoerceExpr(coerce, disjunctionChoice);

lib/Sema/CSDiag.cpp

@@ -6077,7 +6077,7 @@ bool FailureDiagnosis::visitInOutExpr(InOutExpr *IOE) {
 bool FailureDiagnosis::visitCoerceExpr(CoerceExpr *CE) {
   // Coerce the input to whatever type is specified by the CoerceExpr.
   auto expr = typeCheckChildIndependently(CE->getSubExpr(),
-                                          CE->getCastTypeLoc().getType(),
+                                          CS.getType(CE->getCastTypeLoc()),
                                           CTP_CoerceOperand);
   if (!expr)
     return true;
@@ -7922,12 +7922,13 @@ static void noteArchetypeSource(const TypeLoc &loc, ArchetypeType *archetype,
     // `Pair<Any, Any>`.
     // Right now we only handle this when the type that's at fault is the
     // top-level type passed to this function.
-    if (loc.getType().isNull()) {
-      return;
-    }
-    
+    auto type = loc.getType();
+    if (!type)
+      type = cs.getType(loc);
+
     ArrayRef<Type> genericArgs;
-    if (auto *boundGenericTy = loc.getType()->getAs<BoundGenericType>()) {
+
+    if (auto *boundGenericTy = type->getAs<BoundGenericType>()) {
       if (boundGenericTy->getDecl() == FoundDecl)
         genericArgs = boundGenericTy->getGenericArgs();
     }

lib/Sema/CSGen.cpp

@@ -1349,7 +1349,7 @@ namespace {
 
       auto locator = CS.getConstraintLocator(E);
       type = CS.openUnboundGenericType(type, locator);
-      E->getTypeLoc().setType(type, /*validated=*/true);
+      CS.setType(E->getTypeLoc(), type);
       return MetatypeType::get(type);
     }
 
@@ -2521,7 +2521,7 @@ namespace {
       // Open the type we're casting to.
       auto toType = CS.openUnboundGenericType(expr->getCastTypeLoc().getType(),
                                               CS.getConstraintLocator(expr));
-      expr->getCastTypeLoc().setType(toType, /*validated=*/true);
+      CS.setType(expr->getCastTypeLoc(), toType);
 
       auto fromType = CS.getType(fromExpr);
       auto locator = CS.getConstraintLocator(expr);
@@ -2550,7 +2550,7 @@ namespace {
       // Open the type we're casting to.
       auto toType = CS.openUnboundGenericType(expr->getCastTypeLoc().getType(),
                                               CS.getConstraintLocator(expr));
-      expr->getCastTypeLoc().setType(toType, /*validated=*/true);
+      CS.setType(expr->getCastTypeLoc(), toType);
 
       auto fromType = CS.getType(expr->getSubExpr());
       auto locator = CS.getConstraintLocator(expr);
@@ -2584,7 +2584,7 @@ namespace {
       // Open the type we're casting to.
       auto toType = CS.openUnboundGenericType(expr->getCastTypeLoc().getType(),
                                               CS.getConstraintLocator(expr));
-      expr->getCastTypeLoc().setType(toType, /*validated=*/true);
+      CS.setType(expr->getCastTypeLoc(), toType);
 
       auto fromType = CS.getType(fromExpr);
       auto locator = CS.getConstraintLocator(expr);
@@ -2613,7 +2613,7 @@ namespace {
       // FIXME: Locator for the cast type?
       auto toType = CS.openUnboundGenericType(expr->getCastTypeLoc().getType(),
                                               CS.getConstraintLocator(expr));
-      expr->getCastTypeLoc().setType(toType, /*validated=*/true);
+      CS.setType(expr->getCastTypeLoc(), toType);
 
       // Add a checked cast constraint.
       auto fromType = CS.getType(expr->getSubExpr());
@@ -3203,6 +3203,7 @@ namespace {
 
             auto *TE = TypeExpr::createImplicit(joinTy, CS.getASTContext());
             CS.cacheType(TE);
+            CS.setType(TE->getTypeLoc(), joinTy);
 
             auto *DSE = new (CS.getASTContext())
                 DotSelfExpr(TE, SourceLoc(), SourceLoc(), CS.getType(TE));

lib/Sema/ConstraintSystem.h

@@ -969,6 +969,7 @@ class ConstraintSystem {
   /// run through various diagnostics passes without actually mutating
   /// the types on the expression nodes.
   llvm::DenseMap<const Expr *, TypeBase *> ExprTypes;
+  llvm::DenseMap<const TypeLoc *, TypeBase *> TypeLocTypes;
 
   /// Maps closure parameters to type variables.
   llvm::DenseMap<const ParamDecl *, TypeVariableType *>
@@ -1595,12 +1596,21 @@ class ConstraintSystem {
     ExprTypes[E] = T.getPointer();
   }
 
+  void setType(TypeLoc &L, Type T) {
+    assert(T && "Expected non-null type!");
+    TypeLocTypes[&L] = T.getPointer();
+  }
+
   /// Check to see if we have a type for an expression.
   bool hasType(const Expr *E) const {
     assert(E != nullptr && "Expected non-null expression!");
     return ExprTypes.find(E) != ExprTypes.end();
   }
 
+  bool hasType(const TypeLoc &L) const {
+    return TypeLocTypes.find(&L) != TypeLocTypes.end();
+  }
+
   /// Get the type for an expression.
   Type getType(const Expr *E) const {
     assert(hasType(E) && "Expected type to have been set!");
@@ -1611,6 +1621,11 @@ class ConstraintSystem {
     return ExprTypes.find(E)->second;
   }
 
+  Type getType(const TypeLoc &L) const {
+    assert(hasType(L) && "Expected type to have been set!");
+    return TypeLocTypes.find(&L)->second;
+  }
+
   /// Cache the type of the expression argument and return that same
   /// argument.
   template <typename T>

test/Constraints/generics.swift

@@ -188,7 +188,7 @@ func r22459135() {
 
 // <rdar://problem/19710848> QoI: Friendlier error message for "[] as Set"
 // <rdar://problem/22326930> QoI: "argument for generic parameter 'Element' could not be inferred" lacks context
-_ = [] as Set  // expected-error {{generic parameter 'Element' could not be inferred in cast to 'Set<_>}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{14-14=<<#Element: Hashable#>>}}
+_ = [] as Set  // expected-error {{generic parameter 'Element' could not be inferred in cast to 'Set'}} expected-note {{explicitly specify the generic arguments to fix this issue}} {{14-14=<<#Element: Hashable#>>}}
 
 
 //<rdar://problem/22509125> QoI: Error when unable to infer generic archetype lacks greatness

validation-test/compiler_crashers/28823-impl-getgraphindex-typevariables-size-out-of-bounds-index.swift renamed to validation-test/compiler_crashers_fixed/28823-impl-getgraphindex-typevariables-size-out-of-bounds-index.swift

@@ -5,6 +5,6 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+
+// RUN: not %target-swift-frontend %s -emit-ir
 {{}as ManagedBuffer}{

validation-test/compiler_crashers/28856-typevariables-impl-getgraphindex-typevar-type-variable-mismatch.swift renamed to validation-test/compiler_crashers_fixed/28856-typevariables-impl-getgraphindex-typevar-type-variable-mismatch.swift

@@ -5,6 +5,6 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+
+// RUN: not %target-swift-frontend %s -emit-ir
 {[Int?as?ManagedBuffer}{

validation-test/compiler_crashers/28868-known-typebindings-end.swift renamed to validation-test/compiler_crashers_fixed/28868-known-typebindings-end.swift

@@ -5,6 +5,6 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+
+// RUN: not %target-swift-frontend %s -emit-ir
 struct B{func a{a(Int?as?ManagedBuffer{