Remove some more redundant null checks.

PiperOrigin-RevId: 439640674
google · Apr 5, 2022 · fe05664 · fe05664
1 parent fba919b
commit fe05664
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Showing 54 changed files with 44 additions and 178 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/AbstractAsyncTypeReturnsNull.java b/core/src/main/java/com/google/errorprone/bugpatterns/AbstractAsyncTypeReturnsNull.java
@@ -55,9 +55,6 @@ private static Matcher<MethodTree> overridesMethodOfClass(Class<?> clazz) {
       @Override
       public boolean matches(MethodTree tree, VisitorState state) {
         MethodSymbol symbol = getSymbol(tree);
-        if (symbol == null) {
-          return false;
-        }
         for (MethodSymbol superMethod : findSuperMethods(symbol, state.getTypes())) {
           if (superMethod.owner != null
               && superMethod.owner.getQualifiedName().contentEquals(clazz.getName())) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/CacheLoaderNull.java b/core/src/main/java/com/google/errorprone/bugpatterns/CacheLoaderNull.java
@@ -49,9 +49,6 @@ public Description matchMethod(MethodTree tree, VisitorState state) {
       return NO_MATCH;
     }
     MethodSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null) {
-      return NO_MATCH;
-    }
     if (!ASTHelpers.isSubtype(sym.owner.asType(), CACHE_LOADER_TYPE.get(state), state)) {
       return NO_MATCH;
     }

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/ClassCanBeStatic.java b/core/src/main/java/com/google/errorprone/bugpatterns/ClassCanBeStatic.java
@@ -49,7 +49,7 @@ public class ClassCanBeStatic extends BugChecker implements ClassTreeMatcher {
   @Override
   public Description matchClass(ClassTree tree, VisitorState state) {
     ClassSymbol currentClass = ASTHelpers.getSymbol(tree);
-    if (currentClass == null || !currentClass.hasOuterInstance()) {
+    if (!currentClass.hasOuterInstance()) {
       return NO_MATCH;
     }
     if (currentClass.getNestingKind() != NestingKind.MEMBER) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/CompileTimeConstantChecker.java b/core/src/main/java/com/google/errorprone/bugpatterns/CompileTimeConstantChecker.java
@@ -201,9 +201,6 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
   @Override
   public Description matchMethod(MethodTree node, VisitorState state) {
     Symbol.MethodSymbol method = ASTHelpers.getSymbol(node);
-    if (method == null) {
-      return Description.NO_MATCH;
-    }
     List<Integer> compileTimeConstantAnnotationIndexes =
         getAnnotatedParams(method.getParameters(), state);
     if (compileTimeConstantAnnotationIndexes.isEmpty()) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/ConstantField.java b/core/src/main/java/com/google/errorprone/bugpatterns/ConstantField.java
@@ -44,7 +44,7 @@ public class ConstantField extends BugChecker implements VariableTreeMatcher {
   @Override
   public Description matchVariable(VariableTree tree, VisitorState state) {
     Symbol.VarSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null || sym.getKind() != ElementKind.FIELD) {
+    if (sym.getKind() != ElementKind.FIELD) {
       return Description.NO_MATCH;
     }
     String name = sym.getSimpleName().toString();

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/ConstantPatternCompile.java b/core/src/main/java/com/google/errorprone/bugpatterns/ConstantPatternCompile.java
@@ -88,10 +88,7 @@ public Description matchVariable(VariableTree tree, VisitorState state) {
     if (outerMethodTree == null) {
       return NO_MATCH;
     }
-    Symbol sym = getSymbol(tree);
-    if (sym == null) {
-      return NO_MATCH;
-    }
+    VarSymbol sym = getSymbol(tree);
     switch (sym.getKind()) {
       case RESOURCE_VARIABLE:
         return describeMatch(tree);
@@ -115,8 +112,7 @@ private static SuggestedFix fixLocal(
     }
     MethodSymbol methodSymbol = getSymbol(outerMethodTree);
     boolean canUseStatic =
-        (methodSymbol != null
-                && methodSymbol.owner.enclClass().getNestingKind() == NestingKind.TOP_LEVEL)
+        methodSymbol.owner.enclClass().getNestingKind() == NestingKind.TOP_LEVEL
             || outerMethodTree.getModifiers().getFlags().contains(Modifier.STATIC);
     String replacement =
         String.format(

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/DateFormatConstant.java b/core/src/main/java/com/google/errorprone/bugpatterns/DateFormatConstant.java
@@ -56,7 +56,7 @@ public Description matchVariable(VariableTree tree, VisitorState state) {
       return NO_MATCH;
     }
     VarSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null || sym.getKind() != ElementKind.FIELD) {
+    if (sym.getKind() != ElementKind.FIELD) {
       return NO_MATCH;
     }
     String name = sym.getSimpleName().toString();

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/DeduplicateConstants.java b/core/src/main/java/com/google/errorprone/bugpatterns/DeduplicateConstants.java
@@ -158,9 +158,6 @@ private void replaceLiteral(LiteralTree tree, Scope scope, VisitorState state) {
 
       private void saveConstValue(VariableTree tree, Scope scope) {
         VarSymbol sym = ASTHelpers.getSymbol(tree);
-        if (sym == null) {
-          return;
-        }
         if (!isConsideredFinal(sym)) {
           return;
         }

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/DoNotCallChecker.java b/core/src/main/java/com/google/errorprone/bugpatterns/DoNotCallChecker.java
@@ -140,9 +140,6 @@ public class DoNotCallChecker extends BugChecker
   @Override
   public Description matchMethod(MethodTree tree, VisitorState state) {
     MethodSymbol symbol = getSymbol(tree);
-    if (symbol == null) {
-      return NO_MATCH;
-    }
     if (hasAnnotation(tree, DO_NOT_CALL, state)) {
       if (symbol.getModifiers().contains(Modifier.PRIVATE)) {
         return buildDescription(tree)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/DoNotCallSuggester.java b/core/src/main/java/com/google/errorprone/bugpatterns/DoNotCallSuggester.java
@@ -93,9 +93,6 @@ public class DoNotCallSuggester extends BugChecker implements MethodTreeMatcher
   public Description matchMethod(MethodTree tree, VisitorState state) {
     // if we can't find the method symbol, exit
     MethodSymbol symbol = getSymbol(tree);
-    if (symbol == null) {
-      return NO_MATCH;
-    }
 
     // if the method is abstract, exit
     if (tree.getBody() == null) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/EqualsGetClass.java b/core/src/main/java/com/google/errorprone/bugpatterns/EqualsGetClass.java
@@ -87,7 +87,7 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
       return Description.NO_MATCH;
     }
     ClassSymbol classSymbol = getSymbol(classTree);
-    if (classSymbol == null || classSymbol.isAnonymous()) {
+    if (classSymbol.isAnonymous()) {
       return Description.NO_MATCH;
     }
     MethodTree methodTree = (MethodTree) methodTreePath.getLeaf();
@@ -97,8 +97,7 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
     VariableTree parameter = getOnlyElement(methodTree.getParameters());
     ExpressionTree receiver = getReceiver(tree);
     VarSymbol symbol = getSymbol(parameter);
-    if (symbol == null
-        || receiver == null
+    if (receiver == null
         || receiver.getKind() != Kind.IDENTIFIER
         || !symbol.equals(getSymbol(receiver))) {
       return Description.NO_MATCH;

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/FieldCanBeFinal.java b/core/src/main/java/com/google/errorprone/bugpatterns/FieldCanBeFinal.java
@@ -257,7 +257,7 @@ private FinalScanner(VariableAssignmentRecords writes, VisitorState compilationS
     @Override
     public Void visitVariable(VariableTree node, InitializationContext init) {
       VarSymbol sym = ASTHelpers.getSymbol(node);
-      if (sym != null && sym.getKind() == ElementKind.FIELD && !isSuppressed(node)) {
+      if (sym.getKind() == ElementKind.FIELD && !isSuppressed(node)) {
         writes.recordDeclaration(sym, node);
       }
       return super.visitVariable(node, InitializationContext.NONE);
@@ -281,7 +281,7 @@ public Void visitBlock(BlockTree node, InitializationContext init) {
     @Override
     public Void visitMethod(MethodTree node, InitializationContext init) {
       MethodSymbol sym = ASTHelpers.getSymbol(node);
-      if (sym != null && sym.isConstructor()) {
+      if (sym.isConstructor()) {
         init = InitializationContext.INSTANCE;
       }
       return super.visitMethod(node, init);

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/FieldCanBeLocal.java b/core/src/main/java/com/google/errorprone/bugpatterns/FieldCanBeLocal.java
@@ -83,8 +83,7 @@ public Description matchCompilationUnit(CompilationUnitTree tree, VisitorState s
       @Override
       public Void visitVariable(VariableTree variableTree, Void unused) {
         VarSymbol symbol = getSymbol(variableTree);
-        if (symbol != null
-            && symbol.getKind() == ElementKind.FIELD
+        if (symbol.getKind() == ElementKind.FIELD
             && symbol.isPrivate()
             && canBeLocal(variableTree)
             && !shouldKeep(variableTree)) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/FieldCanBeStatic.java b/core/src/main/java/com/google/errorprone/bugpatterns/FieldCanBeStatic.java
@@ -88,8 +88,7 @@ public FieldCanBeStatic(ErrorProneFlags flags) {
   @Override
   public Description matchVariable(VariableTree tree, VisitorState state) {
     VarSymbol symbol = getSymbol(tree);
-    if (symbol == null
-        || !canBeRemoved(symbol)
+    if (!canBeRemoved(symbol)
         || !tree.getModifiers().getFlags().contains(FINAL)
         || symbol.isStatic()
         || !symbol.getKind().equals(FIELD)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/HidingField.java b/core/src/main/java/com/google/errorprone/bugpatterns/HidingField.java
@@ -16,14 +16,14 @@
 package com.google.errorprone.bugpatterns;
 
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.util.ASTHelpers.getSymbol;
 import static java.util.stream.Collectors.toCollection;
 
 import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
 import com.google.errorprone.matchers.Description;
-import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.ClassTree;
 import com.sun.source.tree.VariableTree;
 import com.sun.tools.javac.code.Symbol;
@@ -58,14 +58,10 @@ public Description matchClass(ClassTree classTree, VisitorState visitorState) {
         classTree.getMembers().stream()
             .filter(mem -> mem instanceof VariableTree)
             .map(mem -> (VariableTree) mem)
-            .filter(
-                mem ->
-                    !isSuppressed(ASTHelpers.getSymbol(mem))
-                        && !isIgnoredType(mem)
-                        && !isStatic(mem))
+            .filter(mem -> !isSuppressed(getSymbol(mem)) && !isIgnoredType(mem) && !isStatic(mem))
             .collect(toCollection(ArrayList::new));
 
-    ClassSymbol classSymbol = ASTHelpers.getSymbol(classTree);
+    ClassSymbol classSymbol = getSymbol(classTree);
 
     while (!classSymbol.getSuperclass().getKind().equals(TypeKind.NONE)) {
       TypeSymbol parentSymbol = classSymbol.getSuperclass().asElement();
@@ -123,13 +119,7 @@ private void checkForHiddenFields(
   }
 
   private static boolean isIgnoredType(VariableTree variableTree) {
-    VarSymbol varSymbol = ASTHelpers.getSymbol(variableTree);
-
-    if (varSymbol != null) { // varSymbol is null when variable is primitive type
-      return IGNORED_CLASSES.contains(varSymbol.getQualifiedName().toString());
-    }
-
-    return false;
+    return IGNORED_CLASSES.contains(getSymbol(variableTree).getQualifiedName().toString());
   }
 
   private static boolean isStatic(VariableTree varTree) {
@@ -142,7 +132,7 @@ private static boolean isPackagePrivateAndInDiffPackage(
         && !parentVariable.getModifiers().contains(Modifier.PROTECTED)
         && !parentVariable.getModifiers().contains(Modifier.PUBLIC)) { // package-private variable
 
-      if (!parentVariable.packge().equals(ASTHelpers.getSymbol(currClass).packge())) {
+      if (!parentVariable.packge().equals(getSymbol(currClass).packge())) {
         return true;
       }
     }

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/InfiniteRecursion.java b/core/src/main/java/com/google/errorprone/bugpatterns/InfiniteRecursion.java
@@ -84,7 +84,7 @@ protected MethodInvocationTree defaultAction(Tree tree, Void unused) {
     }
     ExpressionTree select = invocation.getMethodSelect();
     MethodSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null || !sym.equals(ASTHelpers.getSymbol(invocation))) {
+    if (!sym.equals(ASTHelpers.getSymbol(invocation))) {
       return NO_MATCH;
     }
     if (!sym.isStatic()) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/InitializeInline.java b/core/src/main/java/com/google/errorprone/bugpatterns/InitializeInline.java
@@ -55,7 +55,7 @@ public Description matchVariable(VariableTree tree, VisitorState state) {
       return NO_MATCH;
     }
     VarSymbol symbol = getSymbol(tree);
-    if (symbol == null || !isConsideredFinal(symbol)) {
+    if (!isConsideredFinal(symbol)) {
       return NO_MATCH;
     }
     List<TreePath> assignments = new ArrayList<>();

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/InterfaceWithOnlyStatics.java b/core/src/main/java/com/google/errorprone/bugpatterns/InterfaceWithOnlyStatics.java
@@ -61,7 +61,7 @@ public Description matchClass(ClassTree tree, VisitorState state) {
     }
     List<? extends Tree> members = tree.getMembers();
     ClassSymbol symbol = getSymbol(tree);
-    if (symbol == null || !symbol.isInterface() || symbol.isAnnotationType()) {
+    if (!symbol.isInterface() || symbol.isAnnotationType()) {
       return Description.NO_MATCH;
     }
     int staticMembers = 0;

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/IterablePathParameter.java b/core/src/main/java/com/google/errorprone/bugpatterns/IterablePathParameter.java
@@ -48,7 +48,7 @@ public class IterablePathParameter extends BugChecker implements VariableTreeMat
   public Description matchVariable(VariableTree tree, VisitorState state) {
     Type type = ASTHelpers.getType(tree);
     VarSymbol symbol = ASTHelpers.getSymbol(tree);
-    if (type == null || symbol == null) {
+    if (type == null) {
       return NO_MATCH;
     }
     if (symbol.getKind() != ElementKind.PARAMETER) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/JdkObsolete.java b/core/src/main/java/com/google/errorprone/bugpatterns/JdkObsolete.java
@@ -198,9 +198,6 @@ public Description matchClass(ClassTree tree, VisitorState state) {
       return NO_MATCH;
     }
     ClassSymbol symbol = ASTHelpers.getSymbol(tree);
-    if (symbol == null) {
-      return NO_MATCH;
-    }
     return describeIfObsolete(null, state.getTypes().directSupertypes(symbol.asType()), state);
   }
 
@@ -416,9 +413,6 @@ public Void visitMethodInvocation(MethodInvocationTree node, Void unused) {
   private static boolean implementingObsoleteMethod(
       MethodTree enclosingMethod, VisitorState state, Type type) {
     MethodSymbol method = ASTHelpers.getSymbol(enclosingMethod);
-    if (method == null) {
-      return false;
-    }
     if (ASTHelpers.findSuperMethods(method, state.getTypes()).isEmpty()) {
       // not an override
       return false;

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/MemberName.java b/core/src/main/java/com/google/errorprone/bugpatterns/MemberName.java
@@ -84,9 +84,6 @@ public final class MemberName extends BugChecker implements MethodTreeMatcher, V
   @Override
   public Description matchMethod(MethodTree tree, VisitorState state) {
     MethodSymbol symbol = getSymbol(tree);
-    if (symbol == null) {
-      return NO_MATCH;
-    }
     if (!annotationsAmong(symbol.owner, EXEMPTED_CLASS_ANNOTATIONS.get(state), state).isEmpty()) {
       return NO_MATCH;
     }
@@ -138,9 +135,6 @@ private static boolean hasTestAnnotation(MethodSymbol symbol) {
   @Override
   public Description matchVariable(VariableTree tree, VisitorState state) {
     VarSymbol symbol = getSymbol(tree);
-    if (symbol == null) {
-      return NO_MATCH;
-    }
     String name = tree.getName().toString();
     // Try to avoid dual-matching with ConstantCaseForConstants.
     if (UPPER_UNDERSCORE_PATTERN.matcher(name).matches() && !symbol.isStatic()) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/MethodCanBeStatic.java b/core/src/main/java/com/google/errorprone/bugpatterns/MethodCanBeStatic.java
@@ -228,9 +228,6 @@ private void fixQualifier(Tree tree, ExpressionTree qualifierExpression) {
 
   private static boolean isExcluded(MethodTree tree, VisitorState state) {
     MethodSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null) {
-      return true;
-    }
     if (sym.isConstructor() || !disjoint(EXCLUDED_MODIFIERS, sym.getModifiers())) {
       return true;
     }

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/MissingSuperCall.java b/core/src/main/java/com/google/errorprone/bugpatterns/MissingSuperCall.java
@@ -103,9 +103,6 @@ public Description matchAnnotation(AnnotationTree tree, VisitorState state) {
     }
 
     MethodSymbol methodSym = ASTHelpers.getSymbol(methodTree);
-    if (methodSym == null) {
-      return Description.NO_MATCH;
-    }
 
     if (!methodSym.getModifiers().contains(Modifier.ABSTRACT)) {
       return Description.NO_MATCH;
@@ -131,9 +128,6 @@ public Description matchAnnotation(AnnotationTree tree, VisitorState state) {
   @Override
   public Description matchMethod(MethodTree tree, VisitorState state) {
     MethodSymbol methodSym = ASTHelpers.getSymbol(tree);
-    if (methodSym == null) {
-      return Description.NO_MATCH;
-    }
 
     // Allow abstract methods.
     if (methodSym.getModifiers().contains(Modifier.ABSTRACT)) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/NoAllocationChecker.java b/core/src/main/java/com/google/errorprone/bugpatterns/NoAllocationChecker.java
@@ -393,9 +393,6 @@ public Description matchMethod(MethodTree tree, VisitorState state) {
       return NO_MATCH;
     }
     MethodSymbol symbol = ASTHelpers.getSymbol(tree);
-    if (symbol == null) {
-      return NO_MATCH;
-    }
     return findSuperMethods(symbol, state.getTypes()).stream()
         .filter(s -> ASTHelpers.hasAnnotation(s, NoAllocation.class.getName(), state))
         .findAny()

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/NonFinalCompileTimeConstant.java b/core/src/main/java/com/google/errorprone/bugpatterns/NonFinalCompileTimeConstant.java
@@ -47,9 +47,6 @@ public Description matchMethod(MethodTree tree, VisitorState state) {
     }
     for (VariableTree parameter : tree.getParameters()) {
       VarSymbol sym = ASTHelpers.getSymbol(parameter);
-      if (sym == null) {
-        continue;
-      }
       if (!CompileTimeConstantExpressionMatcher.hasCompileTimeConstantAnnotation(state, sym)) {
         continue;
       }

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/NullableConstructor.java b/core/src/main/java/com/google/errorprone/bugpatterns/NullableConstructor.java
@@ -40,9 +40,6 @@ public class NullableConstructor extends BugChecker implements MethodTreeMatcher
   @Override
   public Description matchMethod(MethodTree tree, VisitorState state) {
     Symbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null) {
-      return NO_MATCH;
-    }
     if (!sym.isConstructor()) {
       return NO_MATCH;
     }

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/NullablePrimitive.java b/core/src/main/java/com/google/errorprone/bugpatterns/NullablePrimitive.java
@@ -32,7 +32,6 @@
 import com.sun.source.tree.AnnotationTree;
 import com.sun.source.tree.MethodTree;
 import com.sun.source.tree.VariableTree;
-import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import com.sun.tools.javac.code.Type;
 import java.util.List;
@@ -56,19 +55,12 @@ public Description matchAnnotatedType(AnnotatedTypeTree tree, VisitorState state
   @Override
   public Description matchMethod(MethodTree tree, VisitorState state) {
     MethodSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null) {
-      return NO_MATCH;
-    }
     return check(sym.getReturnType(), tree.getModifiers().getAnnotations());
   }
 
   @Override
   public Description matchVariable(VariableTree tree, VisitorState state) {
-    Symbol.VarSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null) {
-      return NO_MATCH;
-    }
-    return check(sym.type, tree.getModifiers().getAnnotations());
+    return check(ASTHelpers.getSymbol(tree).type, tree.getModifiers().getAnnotations());
   }
 
   private Description check(Type type, List<? extends AnnotationTree> annotations) {

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/NullableVoid.java b/core/src/main/java/com/google/errorprone/bugpatterns/NullableVoid.java
@@ -43,9 +43,6 @@ public class NullableVoid extends BugChecker implements MethodTreeMatcher {
   @Override
   public Description matchMethod(MethodTree tree, VisitorState state) {
     MethodSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null) {
-      return NO_MATCH;
-    }
     if (sym.getReturnType().getKind() != TypeKind.VOID) {
       return NO_MATCH;
     }