[6.3] [Sema] A couple of binding-related crasher fixes

lib/AST/ASTScopeCreation.cpp

@@ -959,11 +959,8 @@ AnnotatedInsertionPoint
 ConditionalClausePatternUseScope::expandAScopeThatCreatesANewInsertionPoint(
     ScopeCreator &scopeCreator) {
   auto *initializer = sec.getInitializer();
-  if (!isa<ErrorExpr>(initializer)) {
-    scopeCreator
-      .constructExpandAndInsert<ConditionalClauseInitializerScope>(
-        this, initializer);
-    }
+  scopeCreator.constructExpandAndInsert<ConditionalClauseInitializerScope>(
+      this, initializer);
 
   return {this,
           "Succeeding code must be in scope of conditional clause pattern bindings"};

lib/Sema/CSGen.cpp

@@ -3153,6 +3153,16 @@ namespace {
       }
 
       case PatternKind::Expr: {
+        // Make sure we invalidate any nested VarDecls early since generating
+        // constraints for a `where` clause may happen before we've generated
+        // constraints for the ExprPattern. We'll record a fix when visiting
+        // the UnresolvedPatternExpr.
+        // FIXME: We ought to use a conjunction for switch cases, then we
+        // wouldn't need this logic.
+        auto *EP = cast<ExprPattern>(pattern);
+        EP->getSubExpr()->forEachUnresolvedVariable([&](VarDecl *VD) {
+          CS.setType(VD, ErrorType::get(CS.getASTContext()));
+        });
         // We generate constraints for ExprPatterns in a separate pass. For
         // now, just create a type variable.
         return setType(CS.createTypeVariable(CS.getConstraintLocator(locator),

validation-test/compiler_crashers_fixed/ConstraintSystem-getTypeOfReferencePre-60045c.swift

@@ -0,0 +1,9 @@
+// {"kind":"typecheck","signature":"swift::constraints::ConstraintSystem::getTypeOfReferencePre(swift::constraints::OverloadChoice, swift::DeclContext*, swift::constraints::ConstraintLocatorBuilder, swift::constraints::PreparedOverloadBuilder*)","signatureAssert":"Assertion failed: (func->isOperator() && \"Lookup should only find operators\"), function getTypeOfReferencePre"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  switch if .random()  else {
+  }
+  {
+  case let !a where a:
+  }
+}

validation-test/compiler_crashers/ConstraintWalker-walkToExprPost-c956e0.swift → validation-test/compiler_crashers_fixed/ConstraintWalker-walkToExprPost-c956e0.swift

@@ -1,5 +1,5 @@
 // {"kind":"typecheck","original":"1562769e","signature":"(anonymous namespace)::ConstraintWalker::walkToExprPost(swift::Expr*)"}
-// RUN: not --crash %target-swift-frontend -typecheck %s
+// RUN: not %target-swift-frontend -typecheck %s
 enum c
   func d()  e {
     if let

validation-test/compiler_crashers_fixed/TypeVarRefCollector-walkToStmtPre-5c070f.swift

@@ -0,0 +1,7 @@
+// {"kind":"typecheck","signature":"swift::constraints::TypeVarRefCollector::walkToStmtPre(swift::Stmt*)","signatureAssert":"Assertion failed: (result), function getClosureType"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  guard let a = (a  if{
+    return
+  }
+) "

validation-test/compiler_crashers_fixed/TypeVarRefCollector-walkToStmtPre-e56ccf.swift

@@ -0,0 +1,10 @@
+// {"kind":"typecheck","signature":"swift::constraints::TypeVarRefCollector::walkToStmtPre(swift::Stmt*)","signatureAssert":"Assertion failed: (result), function getClosureType"}
+// RUN: not %target-swift-frontend -typecheck %s
+{
+  switch if <#expression#> {
+    return
+  }
+  {
+  case let !a where a:
+  }
+}