Clean up implementation, add more tests

Author: calda

lib/Parse/ParseStmt.cpp

@@ -1626,16 +1626,16 @@ Parser::parseStmtConditionElement(SmallVectorImpl<StmtConditionElement> &result,
     SyntaxParsingContext InitCtxt(SyntaxContext, SyntaxKind::InitializerClause);
     consumeToken();
     Init = parseExprBasic(diag::expected_expr_conditional_var);
-  } else if (!ThePattern.isNull() && !ThePattern.getPtrOrNull()->getBoundName().empty()) {
-    auto bindingName = new DeclNameRef(ThePattern.getPtrOrNull()->getBoundName());
-    auto loc = new DeclNameLoc(ThePattern.getPtrOrNull()->getEndLoc());
-    auto declRefExpr = new (Context) UnresolvedDeclRefExpr(*bindingName,
+  } else if (!ThePattern.getPtrOrNull()->getBoundName().empty()) {
+    auto bindingName = DeclNameRef(ThePattern.getPtrOrNull()->getBoundName());
+    auto loc = DeclNameLoc(ThePattern.getPtrOrNull()->getEndLoc());
+    auto declRefExpr = new (Context) UnresolvedDeclRefExpr(bindingName,
                                                            DeclRefKind::Ordinary,
-                                                           *loc);
+                                                           loc);
 
     declRefExpr->setImplicit();
     Init = makeParserResult(declRefExpr);
-  } else if (!ThePattern.isNull() && BindingKindStr != "case") {
+  } else if (BindingKindStr != "case") {
     // If the pattern is present but isn't an identifier, the user wrote
     // something invalid like `let foo.bar`. Emit a special diagnostic for this,
     // with a fix-it prepending "<#identifier#> = "

test/stmt/if_while_var.swift

@@ -48,9 +48,19 @@ if var nonOptional.property { } // expected-error{{unwrap condition requires a v
 guard let _ = nonOptionalStruct() else { fatalError() } // expected-error{{initializer for conditional binding must have Optional type, not 'NonOptionalStruct'}}
 guard let _ = nonOptionalEnum() else { fatalError() } // expected-error{{initializer for conditional binding must have Optional type, not 'NonOptionalEnum'}}
 
+let optional: String? = nil
+if case let optional? { _ = optional } // expected-error{{variable binding in a condition requires an initializer}}
+if case let .some(optional) { _ = optional } // expected-error{{variable binding in a condition requires an initializer}}
+if case .some(let optional) { _ = optional } // expected-error{{variable binding in a condition requires an initializer}}
+
 if case let x? = nonOptionalStruct() { _ = x } // expected-error{{'?' pattern cannot match values of type 'NonOptionalStruct'}}
 if case let x? = nonOptionalEnum() { _ = x } // expected-error{{'?' pattern cannot match values of type 'NonOptionalEnum'}}
 
+if let x { _ = x } // expected-error{{cannot find 'x' in scope}}
+
+if let optional: String { _ = optional }
+if let optional: Int { _ = optional } // expected-error{{cannot convert value of type 'String?' to specified type 'Int?'}}
+
 class B {} // expected-note * {{did you mean 'B'?}}
 class D : B {}// expected-note * {{did you mean 'D'?}}