[Sema] Remove some hasError checks for typeCheckPattern

These shouldn't be necessary anymore, we should be able to handle
ErrorType patterns.

Author: hamishknight

lib/Sema/CSGen.cpp

@@ -4823,12 +4823,6 @@ generateForEachPreambleConstraints(ConstraintSystem &cs,
     return std::nullopt;
   target.setPattern(pattern);
 
-  auto contextualPattern = ContextualPattern::forRawPattern(pattern, dc);
-
-  if (TypeChecker::typeCheckPattern(contextualPattern)->hasError()) {
-    return std::nullopt;
-  }
-
   if (isa<PackExpansionExpr>(forEachExpr)) {
     auto *expansion = cast<PackExpansionExpr>(forEachExpr);
 
@@ -4996,10 +4990,6 @@ bool ConstraintSystem::generateConstraints(
           ContextualPattern::forPatternBindingDecl(patternBinding, index);
       Type patternType = TypeChecker::typeCheckPattern(contextualPattern);
 
-      // Fail early if pattern couldn't be type-checked.
-      if (!patternType || patternType->hasError())
-        return true;
-
       auto *init = patternBinding->getInit(index);
 
       if (!init && patternBinding->isDefaultInitializable(index) &&

lib/Sema/TypeCheckStmt.cpp

@@ -905,10 +905,6 @@ typeCheckPatternBindingStmtConditionElement(StmtConditionElement &elt,
   // provide type information.
   auto contextualPattern = ContextualPattern::forRawPattern(pattern, dc);
   Type patternType = TypeChecker::typeCheckPattern(contextualPattern);
-  if (patternType->hasError()) {
-    typeCheckPatternFailed();
-    return true;
-  }
 
   // If the pattern didn't get a type, it's because we ran into some
   // unknown types along the way. We'll need to check the initializer.

lib/Sema/TypeCheckStorage.cpp

@@ -451,12 +451,6 @@ const PatternBindingEntry *PatternBindingEntryRequest::evaluate(
   auto contextualPattern =
       ContextualPattern::forPatternBindingDecl(binding, entryNumber);
   Type patternType = TypeChecker::typeCheckPattern(contextualPattern);
-  if (patternType->hasError()) {
-    swift::setBoundVarsTypeError(pattern, Context);
-    binding->setInvalid();
-    pattern->setType(ErrorType::get(Context));
-    return &pbe;
-  }
 
   llvm::SmallVector<VarDecl *, 2> vars;
   binding->getPattern(entryNumber)->collectVariables(vars);

test/Constraints/generics.swift

@@ -472,7 +472,9 @@ do {
 }
 
 class testStdlibType {
-  let _: Array // expected-error {{reference to generic type 'Array' requires arguments in <...>}} {{15-15=<Any>}}
+  let _: Array
+  // expected-error@-1 {{reference to generic type 'Array' requires arguments in <...>}} {{15-15=<Any>}}
+  // expected-error@-2 {{property declaration does not bind any variables}}
 }
 
 // rdar://problem/32697033

test/Constraints/patterns.swift

@@ -840,4 +840,7 @@ func testUndefinedInClosureVar() {
   _ = {
     var x: Undefined // expected-error {{cannot find type 'Undefined' in scope}}
   }
+  _ = {
+    for x: Undefined in [0] {} // expected-error {{cannot find type 'Undefined' in scope}}
+  }
 }