linter: Report when single statement if-statement body is not on the …

…same line as if-keyword

Fixes dart-lang/linter#4870

Cq-Include-Trybots: luci.dart.try:flutter-analyze-try,analyzer-win-release-try
Change-Id: Ibd8969afe35f719a020e5aa37efdc1792addac7e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/353140
Reviewed-by: Stephen Adams <sra@google.com>
Reviewed-by: Phil Quitslund <pquitslund@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>

pkg/_js_interop_checks/lib/src/transformations/js_util_optimizer.dart

@@ -1082,7 +1082,9 @@ class ExtensionIndex {
   /// If not an interop extension type or extension member, returns null.
   FunctionType? getFunctionType(Procedure node) {
     if (getExtensionDescriptor(node) == null &&
-        getExtensionTypeDescriptor(node) == null) return null;
+        getExtensionTypeDescriptor(node) == null) {
+      return null;
+    }
 
     final functionType = node.signatureType ??
         node.function.computeFunctionType(Nullability.nonNullable);

pkg/front_end/lib/src/base/export.dart

@@ -39,7 +39,9 @@ class Export {
         if (combinator.isShow && !combinator.names.contains(name)) return false;
         if (combinator.isHide &&
             // Coverage-ignore(suite): Not run.
-            combinator.names.contains(name)) return false;
+            combinator.names.contains(name)) {
+          return false;
+        }
       }
     }
     return exporter.libraryBuilder.addToExportScope(name, member,

pkg/front_end/lib/src/base/incremental_compiler.dart

@@ -1765,7 +1765,9 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       Uri? partFileUri = uriTranslator.getPartFileUri(lib.fileUri, part);
       if (partsUsed != null &&
           // Coverage-ignore(suite): Not run.
-          partsUsed.contains(partFileUri)) continue;
+          partsUsed.contains(partFileUri)) {
+        continue;
+      }
 
       // If the builders map contain the "parts" import uri, it's a real library
       // (erroneously) used as a part so we don't want to remove that.

pkg/front_end/tool/coverage_merger.dart

@@ -739,7 +739,9 @@ void _mergeCoverageInto(
     Coverage coverage, Map<Uri, Set<int>> misses, Map<Uri, Hit> hits) {
   for (FileCoverage fileCoverage in coverage.getAllFileCoverages()) {
     if (fileCoverage.uri.isScheme("package") &&
-        fileCoverage.uri.pathSegments.first != "front_end") continue;
+        fileCoverage.uri.pathSegments.first != "front_end") {
+      continue;
+    }
     if (fileCoverage.misses.isNotEmpty) {
       Set<int> miss = misses[fileCoverage.uri] ??= {};
       miss.addAll(fileCoverage.misses);
@@ -1013,7 +1015,9 @@ class AstIndexerAndIgnoreCollector extends AstIndexer {
     // possible "double-ignored" coverages should still work fine because of the
     // interval list.
     if (_checkCommentAndIgnoreCoverage(node.beginToken, node,
-        allowReplace: false)) return;
+        allowReplace: false)) {
+      return;
+    }
     super.visitClassDeclarationEnd(node);
   }
 
@@ -1024,7 +1028,9 @@ class AstIndexerAndIgnoreCollector extends AstIndexer {
     // possible "double-ignored" coverages should still work fine because of the
     // interval list.
     if (_checkCommentAndIgnoreCoverage(node.beginToken, node,
-        allowReplace: false)) return;
+        allowReplace: false)) {
+      return;
+    }
     super.visitExtensionDeclarationEnd(node);
   }
 
@@ -1035,7 +1041,9 @@ class AstIndexerAndIgnoreCollector extends AstIndexer {
     // possible "double-ignored" coverages should still work fine because of the
     // interval list.
     if (_checkCommentAndIgnoreCoverage(node.beginToken, node,
-        allowReplace: false)) return;
+        allowReplace: false)) {
+      return;
+    }
     super.visitExtensionTypeDeclarationEnd(node);
   }
 
@@ -1064,7 +1072,9 @@ class AstIndexerAndIgnoreCollector extends AstIndexer {
   @override
   void visitTopLevelMethodEnd(TopLevelMethodEnd node) {
     if (_checkCommentAndIgnoreCoverage(node.beginToken, node,
-        allowReplace: false)) return;
+        allowReplace: false)) {
+      return;
+    }
     super.visitTopLevelMethodEnd(node);
     String name = node.getNameIdentifier().token.lexeme;
     if (topLevelMethodNamesToIgnore.contains(name)) {

pkg/linter/lib/src/rules/curly_braces_in_flow_control_structures.dart

@@ -32,8 +32,8 @@ if (isWeekDay) {
 ```
 
 There is one exception to this: an `if` statement with no `else` clause where
-the entire `if` statement and the then body all fit in one line. In that case,
-you may leave off the braces if you prefer:
+the entire `if` statement (including the condition and the body) fits in one
+line. In that case, you may leave off the braces if you prefer:
 
 **GOOD:**
 ```dart
@@ -105,7 +105,7 @@ class _Visitor extends SimpleAstVisitor {
 
       var unit = node.root as CompilationUnit;
       var lineInfo = unit.lineInfo;
-      if (lineInfo.getLocation(node.rightParenthesis.end).lineNumber !=
+      if (lineInfo.getLocation(node.ifKeyword.offset).lineNumber !=
           lineInfo.getLocation(node.thenStatement.end).lineNumber) {
         rule.reportLint(node.thenStatement, arguments: ['an if']);
       }

pkg/linter/lib/src/rules/use_string_buffers.dart

@@ -122,7 +122,9 @@ class _UseStringBufferVisitor extends SimpleAstVisitor {
   @override
   void visitAssignmentExpression(AssignmentExpression node) {
     if (node.operator.type != TokenType.PLUS_EQ &&
-        node.operator.type != TokenType.EQ) return;
+        node.operator.type != TokenType.EQ) {
+      return;
+    }
 
     var left = node.leftHandSide;
     var writeType = node.writeType;

pkg/linter/test/rules/curly_braces_in_flow_control_structures_test.dart

@@ -165,6 +165,17 @@ void f() {
 ''');
   }
 
+  test_ifStatement_singleStatement_sameLine_multiLineCondition() async {
+    await assertDiagnostics(r'''
+void f() {
+  if (1 ==
+      2) return;
+}
+''', [
+      lint(31, 7),
+    ]);
+  }
+
   test_ifStatementElse_block_sameLine() async {
     await assertNoDiagnostics(r'''
 void f() {