Merge pull request swiftlang#210 from karwa/SR-13194

[SR-13194] DoNotUseSemicolons should not strip semicolons which separate a 'do' blocks from 'while' blocks.

Author: allevato

Sources/SwiftFormatRules/DoNotUseSemicolons.swift

@@ -53,6 +53,7 @@ public final class DoNotUseSemicolons: SyntaxFormatRule {
  }
 
  var newItem = visitedItem
+ defer { newItems[idx] = newItem }
 
  // Check if the leading trivia for this statement needs a new line.
  if previousHadSemicolon, let firstToken = newItem.firstToken,
@@ -68,6 +69,19 @@ public final class DoNotUseSemicolons: SyntaxFormatRule {
 
  // If there's a semicolon, diagnose and remove it.
  if let semicolon = item.semicolon {
+
+ // Exception: do not remove the semicolon if it is separating a 'do' statement from a 'while' statement.
+ if Syntax(item).as(CodeBlockItemSyntax.self)?.children.first?.is(DoStmtSyntax.self) == true,
+ idx < node.count - 1
+ {
+ let nextItem = node.children[node.children.index(after: item.index)]
+ if Syntax(nextItem).as(CodeBlockItemSyntax.self)?
+ .children.first?.is(WhileStmtSyntax.self) == true
+ {
+ continue
+ }
+ }
+
  // This discards any trailingTrivia from the semicolon. That trivia is at most some spaces,
  // and the pretty printer adds any necessary spaces so it's safe to discard.
  newItem = newItem.withSemicolon(nil)
@@ -77,7 +91,6 @@ public final class DoNotUseSemicolons: SyntaxFormatRule {
  diagnose(.removeSemicolon, on: semicolon)
  }
  }
- newItems[idx] = newItem
  }
  return nodeCreator(newItems)
  }

Tests/SwiftFormatRulesTests/DoNotUseSemicolonsTests.swift

@@ -89,4 +89,41 @@ final class DoNotUseSemicolonsTests: LintOrFormatRuleTestCase {
  print("7")
  """)
  }
+ 
+ func testSemicolonsSeparatingDoWhile() {
+ XCTAssertFormatting(
+ DoNotUseSemicolons.self,
+ input: """
+ do { f() };
+ while someCondition { g() }
+
+ do {
+ f()
+ };
+
+ // Comment and whitespace separating blocks.
+ while someCondition {
+ g()
+ }
+
+ do { f() };
+ for _ in 0..<10 { g() }
+ """,
+ expected: """
+ do { f() };
+ while someCondition { g() }
+
+ do {
+ f()
+ };
+
+ // Comment and whitespace separating blocks.
+ while someCondition {
+ g()
+ }
+
+ do { f() }
+ for _ in 0..<10 { g() }
+ """)
+ }
 }