[Multi-expression closures] Add support for do-catch statements.

Author: DougGregor

lib/Sema/CSClosure.cpp

@@ -233,19 +233,32 @@ class ClosureConstraintGenerator
     assert(subjectExpr && "Must have a subject expression here");
 
     // Visit the raw cases.
+    auto subjectLocator = cs.getConstraintLocator(
+        subjectExpr, LocatorPathElt::ContextualType());
+    Type subjectType = cs.getType(subjectExpr);
     for (auto rawCase : switchStmt->getRawCases()) {
-      if (auto decl = rawCase.dyn_cast<Decl *>())
+      if (auto decl = rawCase.dyn_cast<Decl *>()) {
         visitDecl(decl);
-      else
-        visitCaseStmt(cast<CaseStmt>(rawCase.get<Stmt *>()), subjectExpr);
+      } else {
+        visitCaseStmt(
+            cast<CaseStmt>(rawCase.get<Stmt *>()), subjectType, subjectLocator);
+      }
     }
   }
 
-  void visitCaseStmt(CaseStmt *caseStmt, Expr *subjectExpr) {
-    auto locator = cs.getConstraintLocator(
-        subjectExpr, LocatorPathElt::ContextualType());
-    Type subjectType = cs.getType(subjectExpr);
+  void visitDoCatchStmt(DoCatchStmt *doCatchStmt) {
+    visit(doCatchStmt->getBody());
+
+    // Visit the "catch" blocks.
+    Type exceptionType = cs.getASTContext().getExceptionType();
+    for (auto catchStmt : doCatchStmt->getCatches()) {
+      auto locator = cs.getConstraintLocator(catchStmt);
+      visitCaseStmt(catchStmt, exceptionType, locator);
+    }
+  }
 
+  void visitCaseStmt(
+      CaseStmt *caseStmt, Type subjectType, ConstraintLocator *locator) {
     if (cs.generateConstraints(caseStmt, closure, subjectType, locator)) {
       hadError = true;
       return;
@@ -261,7 +274,6 @@ class ClosureConstraintGenerator
       llvm_unreachable("Unsupported statement kind " #STMT);          \
   }
   UNSUPPORTED_STMT(Yield)
-  UNSUPPORTED_STMT(DoCatch)
   UNSUPPORTED_STMT(Case)
   UNSUPPORTED_STMT(Fail)
 #undef UNSUPPORTED_STMT
@@ -585,6 +597,19 @@ class ClosureConstraintApplication
     return switchStmt;
   }
 
+  ASTNode visitDoCatchStmt(DoCatchStmt *doCatchStmt) {
+    // Translate the body.
+    auto newBody = visit(doCatchStmt->getBody());
+    doCatchStmt->setBody(newBody.get<Stmt *>());
+
+    // Visit the catch blocks.
+    for (auto catchStmt : doCatchStmt->getCatches()) {
+      visitCaseStmt(catchStmt);
+    }
+
+    return doCatchStmt;
+  }
+
   ASTNode visitCaseStmt(CaseStmt *caseStmt) {
     // Translate the patterns and guard expressions for each case label item.
     for (auto &caseLabelItem : caseStmt->getMutableCaseLabelItems()) {
@@ -610,7 +635,6 @@ class ClosureConstraintApplication
       llvm_unreachable("Unsupported statement kind " #STMT);          \
   }
   UNSUPPORTED_STMT(Yield)
-  UNSUPPORTED_STMT(DoCatch)
   UNSUPPORTED_STMT(Fail)
 #undef UNSUPPORTED_STMT
 

lib/Sema/TypeCheckConstraints.cpp

@@ -1318,6 +1318,10 @@ namespace {
     std::pair<bool, Stmt *> walkToStmtPre(Stmt *stmt) override {
       return { true, stmt };
     }
+
+    std::pair<bool, Pattern *> walkToPatternPre(Pattern *pattern) override {
+      return { false, pattern };
+    }
   };
 } // end anonymous namespace
 

lib/Sema/TypeCheckStmt.cpp

@@ -1324,8 +1324,8 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
     // There is nothing more to do.
     return S;
   }
-
 };
+
 } // end anonymous namespace
 
 static bool isDiscardableType(Type type) {

test/expr/closure/multi_statement.swift

@@ -10,6 +10,8 @@ func maybeGetValue<T>(_ value: T) -> T? {
 
 enum MyError: Error {
   case featureIsTooCool
+
+  func doIt() { }
 }
 
 enum State {
@@ -20,6 +22,8 @@ enum State {
 
 func random(_: Int) -> Bool { return false }
 
+func mightThrow() throws -> Bool { throw MyError.featureIsTooCool }
+
 func mapWithMoreStatements(ints: [Int], state: State) throws {
   let _ = try ints.map { i in
     guard var actualValue = maybeGetValue(i) else {
@@ -76,6 +80,13 @@ func mapWithMoreStatements(ints: [Int], state: State) throws {
 
     #assert(true)
 
+    do {
+      print(try mightThrow())
+    } catch let e as MyError {
+      e.doIt()
+    } catch {
+      print(error)
+    }
     return String(value)
   }
 }