[TypeChecker] NFC: Include constraint system into TypeChecker header

Avoids having to include ConstraintSystem.h in TypeCheck*.cpp
files to gain access to ContextualInfo and related classes.

Author: xedin

lib/Sema/DebuggerTestingTransform.cpp

@@ -29,7 +29,6 @@
 #include "swift/Subsystems.h"
 
 #include "TypeChecker.h"
-#include "ConstraintSystem.h"
 
 using namespace swift;
 

lib/Sema/InstrumenterSupport.h

@@ -16,7 +16,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "TypeChecker.h"
-#include "ConstraintSystem.h"
 #include "swift/AST/ASTWalker.h"
 
 namespace swift {

lib/Sema/TypeCheckCodeCompletion.cpp

@@ -962,8 +962,7 @@ bool swift::typeCheckExpression(DeclContext *DC, Expr *&parsedExpr) {
   parsedExpr = parsedExpr->walk(SanitizeExpr(ctx, /*shouldReusePrecheckedType=*/false));
 
   DiagnosticSuppression suppression(ctx.Diags);
-  auto resultTy =
-      TypeChecker::typeCheckExpression(parsedExpr, DC, /*contextualInfo=*/{});
+  auto resultTy = TypeChecker::typeCheckExpression(parsedExpr, DC);
   return !resultTy;
 }
 

lib/Sema/TypeCheckConstraints.cpp

@@ -594,7 +594,7 @@ bool TypeChecker::typeCheckCondition(Expr *&expr, DeclContext *dc) {
   // re-typecheck it.
   if (expr->getType() && expr->getType()->isBool()) {
     auto resultTy =
-        TypeChecker::typeCheckExpression(expr, dc, /*contextualInfo=*/{});
+        TypeChecker::typeCheckExpression(expr, dc);
     return !resultTy;
   }
 

lib/Sema/TypeCheckDecl.cpp

@@ -15,7 +15,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeSynthesis.h"
-#include "ConstraintSystem.h"
 #include "DerivedConformances.h"
 #include "TypeChecker.h"
 #include "TypeCheckAccess.h"

lib/Sema/TypeCheckStmt.cpp

@@ -18,7 +18,6 @@
 #include "TypeCheckAvailability.h"
 #include "TypeCheckType.h"
 #include "MiscDiagnostics.h"
-#include "ConstraintSystem.h"
 #include "swift/Subsystems.h"
 #include "swift/AST/ASTPrinter.h"
 #include "swift/AST/ASTWalker.h"
@@ -882,7 +881,7 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
     TypeChecker::typeCheckDecl(DS->getTempDecl());
 
     Expr *theCall = DS->getCallExpr();
-    TypeChecker::typeCheckExpression(theCall, DC, /*contextualInfo=*/{});
+    TypeChecker::typeCheckExpression(theCall, DC);
     DS->setCallExpr(theCall);
 
     return DS;
@@ -1156,8 +1155,7 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
   Stmt *visitSwitchStmt(SwitchStmt *switchStmt) {
     // Type-check the subject expression.
     Expr *subjectExpr = switchStmt->getSubjectExpr();
-    auto resultTy = TypeChecker::typeCheckExpression(subjectExpr, DC,
-                                                     /*contextualInfo=*/{});
+    auto resultTy = TypeChecker::typeCheckExpression(subjectExpr, DC);
     auto limitExhaustivityChecks = !resultTy;
     if (Expr *newSubjectExpr =
             TypeChecker::coerceToRValue(getASTContext(), subjectExpr))

lib/Sema/TypeCheckStorage.cpp

@@ -17,7 +17,6 @@
 
 #include "CodeSynthesis.h"
 #include "TypeChecker.h"
-#include "ConstraintSystem.h"
 #include "TypeCheckAvailability.h"
 #include "TypeCheckDecl.h"
 #include "TypeCheckType.h"
@@ -917,8 +916,7 @@ static Expr *buildStorageReference(AccessorDecl *accessor,
     // FIXME: Since we're not resolving overloads or anything, we should be
     // building fully type-checked AST above; we already have all the
     // information that we need.
-    if (!TypeChecker::typeCheckExpression(lookupExpr, accessor,
-                                          /*contextualInfo=*/{}))
+    if (!TypeChecker::typeCheckExpression(lookupExpr, accessor))
       return nullptr;
 
     // Make sure we produce an lvalue only when desired.

lib/Sema/TypeChecker.h

@@ -17,6 +17,7 @@
 #ifndef TYPECHECKING_H
 #define TYPECHECKING_H
 
+#include "ConstraintSystem.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/AccessScope.h"
 #include "swift/AST/AnyFunctionRef.h"
@@ -51,7 +52,6 @@ namespace constraints {
   class Solution;
   class SolutionApplicationTarget;
   class SolutionResult;
-  struct ContextualTypeInfo;
 }
 
 /// Special-case type checking semantics for certain declarations.
@@ -561,7 +561,7 @@ Expr *findLHS(DeclContext *DC, Expr *E, Identifier name);
 /// \returns The type of the top-level expression, or Type() if an
 ///          error occurred.
 Type typeCheckExpression(Expr *&expr, DeclContext *dc,
-                         constraints::ContextualTypeInfo contextualInfo,
+                         constraints::ContextualTypeInfo contextualInfo = {},
                          TypeCheckExprOptions options = TypeCheckExprOptions());
 
 Optional<constraints::SolutionApplicationTarget>