Func reference prevent unused func inspection

build.gradle

@@ -35,6 +35,7 @@ task parser(type: org.jetbrains.grammarkit.tasks.GenerateParser) {
 
 // See https://github.com/JetBrains/gradle-intellij-plugin/
 intellij {
+    downloadSources = true // https://plugins.jetbrains.com/docs/intellij/tools-gradle-intellij-plugin.html#ide-configuration
     version = '2021.1.3'
     plugins = ['com.intellij.java']
 }

src/main/java/intellij_awk/Awk.bnf

@@ -348,7 +348,7 @@ non_unary_expr   ::= (
                          | NOT expr
                          | simple_get (LT expr)?
                          | NUMBER
-                         | STRING
+                         | str
                          | ERE
                          | INCR lvalue
                          | DECR lvalue
@@ -391,6 +391,12 @@ function_call_name          ::= FUNC_NAME
     implements="intellij_awk.psi.AwkNamedElement"
 }
 
+str          ::= STRING  // we need this as PSI to enable GAWK's function references `f="fname"; @f()`
+{
+    mixin="intellij_awk.psi.AwkStringMixin"
+    implements="intellij_awk.psi.AwkNamedElement"
+}
+
 private non_unary_expr1     ::= [
                           (     POW      expr
                               | MUL      expr
@@ -449,7 +455,7 @@ private non_unary_print_expr ::= (
                      | LPAREN expr_lst RPAREN IN gawk_var_name
                      | simple_get
                      | NUMBER
-                     | STRING
+                     | str
                      | ERE
                      | INCR lvalue
                      | DECR lvalue

src/main/java/intellij_awk/AwkCompletionContributorBase.java

@@ -15,18 +15,18 @@
 abstract class AwkCompletionContributorBase extends CompletionContributor {
   static final PsiElementPattern.Capture<PsiElement> INSIDE_STRING = psiElement(AwkTypes.STRING);
   private static final ElementPattern<PsiElement> notInsideERE =
-          not(or(psiElement(AwkTypes.ERE), psiElement(AwkTypes.TYPED_ERE)));
+      not(or(psiElement(AwkTypes.ERE), psiElement(AwkTypes.TYPED_ERE)));
 
   private static final ObjectPattern.Capture<PsiElement> notInsideStringEre =
-          not(INSIDE_STRING).and(notInsideERE);
+      not(INSIDE_STRING).and(notInsideERE);
 
   static ElementPattern<? extends PsiElement> notInsideStringERE(
-          ElementPattern<? extends PsiElement> pattern) {
+      ElementPattern<? extends PsiElement> pattern) {
     return and(notInsideStringEre, pattern);
   }
 
   static ElementPattern<? extends PsiElement> notInsideERE(
-          ElementPattern<? extends PsiElement> pattern) {
+      ElementPattern<? extends PsiElement> pattern) {
     return and(notInsideERE, pattern);
   }
 

src/main/java/intellij_awk/AwkInspectionUnresolvedFunction.java

@@ -124,7 +124,7 @@ public void invoke(@NotNull Project project, Editor editor, PsiFile file)
             }
           }
           if (name == null) {
-            PsiElement string = nonUnaryExpr.getString();
+            PsiElement string = nonUnaryExpr.getStr();
             if (string != null && string.getText().equals(nonUnaryExpr.getText())) {
               String text = string.getText();
               name = text.substring(1, text.length() - 1);

src/main/java/intellij_awk/AwkParserDefinition.java

@@ -26,7 +26,7 @@ public class AwkParserDefinition implements ParserDefinition {
       new IStubFileElementType<>(AwkLanguage.INSTANCE) {
         @Override
         public int getStubVersion() {
-          return 15;
+          return 16;
         }
 
         @Override

src/main/java/intellij_awk/psi/AwkElementFactory.java

@@ -18,6 +18,11 @@ public static AwkFunctionName createFunctionName(Project project, String name) {
     return createAwkPsiElement(project, "function " + name + "(){}", AwkFunctionName.class);
   }
 
+  public static AwkStr createString(Project project, String str) {
+    return createAwkPsiElement(
+        project, "{ a = \"" + str.replace("\"", "\\\"") + "\" }", AwkStr.class);
+  }
+
   public static AwkItem createFunctionItem(Project project, String name) {
     return createAwkPsiElement(project, "function " + name + "(){}", AwkItem.class);
   }

src/main/java/intellij_awk/psi/AwkStringMixin.java

@@ -0,0 +1,69 @@
+package intellij_awk.psi;
+
+import static com.intellij.openapi.util.text.StringUtil.unquoteString;
+
+import com.intellij.lang.ASTNode;
+import com.intellij.openapi.util.TextRange;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiReference;
+import intellij_awk.AwkReferenceFunction;
+import intellij_awk.AwkUtil;
+import java.util.regex.Pattern;
+import javax.swing.*;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public abstract class AwkStringMixin extends AwkNamedElementImpl {
+  public AwkStringMixin(@NotNull ASTNode node) {
+    super(node);
+  }
+
+  private static final Pattern stringThatCanBeFunctionName =
+      Pattern.compile("\"[A-Za-z_][A-Za-z0-9_]*\"");
+
+  @Override
+  public String getName() {
+    return getPossibleFunctionName();
+  }
+
+  @Nullable
+  private String getPossibleFunctionName() {
+    String str = getText();
+    return canBeFunctionName(str) ? unquoteString(str) : null;
+  }
+
+  static boolean canBeFunctionName(String s) {
+    return stringThatCanBeFunctionName.matcher(s).matches();
+  }
+
+  public PsiElement setName(String newName) {
+    return replaceNameNode(AwkElementFactory.createString(getProject(), newName));
+  }
+
+  @Override
+  public PsiReference getReference() {
+    return getPossibleFunctionName() != null && canBeFunctionReference()
+        ? new AwkReferenceFunction(this, TextRange.from(1, getTextLength() - 2))
+        : null;
+  }
+
+  private boolean canBeFunctionReference() {
+    return isRhsOfAssignment() || isUserFunctionArgument();
+  }
+
+  /** `f("fname")` but not `substr("fname")` (built-in) */
+  private boolean isUserFunctionArgument() {
+    AwkGawkFuncCallList callList = AwkUtil.findParent(this, AwkGawkFuncCallList.class);
+    return callList != null && callList.getParent() instanceof AwkFunctionCallUser;
+  }
+
+  /** `a = "fname"` */
+  private boolean isRhsOfAssignment() {
+    return AwkUtil.isType(AwkUtil.getPrevNotWhitespace(getParent()), AwkTypes.ASSIGN);
+  }
+
+  @Override
+  public @Nullable Icon getIcon(int flags) {
+    return null;
+  }
+}

src/test/java/intellij_awk/AwkInspectionTests.java

@@ -102,20 +102,21 @@ public void testIssue203NoUnusedFunctionErrForUsageInOtherFile() {
     myFixture.addFileToProject("c.awk", "BEGIN { f() } ");
     assertNoInspectionAtCaret(unusedFunction);
   }
+
   public void testIssue203NoUnusedFunctionErrForRepeatingDefinitionInSeparateFiles() {
     myFixture.configureByText("a.awk", "function <caret>f(){}");
     myFixture.addFileToProject("b.awk", "function f() {}");
     myFixture.addFileToProject("c.awk", "BEGIN { f() } ");
     assertNoInspectionAtCaret(unusedFunction);
   }
 
-  public void testIssue203UnusedFunctionErrForRepeatingDefinitionWhenFunctionIsUsedInSameFileAsDefined() {
+  public void
+      testIssue203UnusedFunctionErrForRepeatingDefinitionWhenFunctionIsUsedInSameFileAsDefined() {
     myFixture.configureByText("a.awk", "function <caret>f(){}");
     myFixture.addFileToProject("c.awk", "BEGIN { f() } function f() {}");
     assertInspectionIsShown(unusedFunction);
   }
 
-
   public void testUsedVarInFileOutsideProject() {
     checkByFileNoProblemAtCaret(unusedGlobalVariable, true);
   }
@@ -299,6 +300,38 @@ public void testUnnecessarySemicolonNecessary4() {
     checkByFileNoProblemAtCaret(unnecessarySemicolon);
   }
 
+  public void testFuncRefToPreventUnusedFunc1() {
+    checkByFileNoProblemAtCaret(unusedFunction);
+  }
+
+  public void testFuncRefToPreventUnusedFunc1_1() {
+    checkByFile(unusedFunction);
+  }
+
+  public void testFuncRefToPreventUnusedFunc2() {
+    checkByFileNoProblemAtCaret(unusedFunction);
+  }
+
+  public void testFuncRefToPreventUnusedFunc2_1() {
+    checkByFile(unusedFunction);
+  }
+
+  public void testFuncRefToPreventUnusedFunc3() {
+    checkByFileNoProblemAtCaret(unusedFunction);
+  }
+
+  public void testFuncRefToPreventUnusedFunc3_1() {
+    checkByFile(unusedFunction);
+  }
+
+  public void testFuncRefToPreventUnusedFunc4() {
+    checkByFileNoProblemAtCaret(unusedFunction);
+  }
+
+  public void testFuncRefToPreventUnusedFunc4_1() {
+    checkByFile(unusedFunction);
+  }
+
   @Override
   protected String getTestDataPath() {
     return "src/test/testData/inspection";

src/test/java/intellij_awk/AwkRenameTests.java

@@ -12,6 +12,7 @@ public class AwkRenameTests extends BasePlatformTestCase {
   public void testVars6() { checkByFile(); }
   public void testVars7() { checkByFile(); }
   public void testFunc1() { checkByFile(); }
+  public void testFuncRef() { checkByFile(); }
   public void testIndirect1() { checkByFile(); }
 
   @Override

src/test/java/intellij_awk/psi/AwkStringMixinTests.java

@@ -0,0 +1,23 @@
+package intellij_awk.psi;
+
+import junit.framework.TestCase;
+import org.junit.Assert;
+
+public class AwkStringMixinTests extends TestCase {
+  public void testTrue() {
+    Assert.assertTrue(AwkStringMixin.canBeFunctionName("\"aaa\""));
+    Assert.assertTrue(AwkStringMixin.canBeFunctionName("\"_aaa01\""));
+    Assert.assertTrue(AwkStringMixin.canBeFunctionName("\"Xxx123\""));
+    Assert.assertTrue(AwkStringMixin.canBeFunctionName("\"_\""));
+    Assert.assertTrue(AwkStringMixin.canBeFunctionName("\"X\""));
+  }
+  public void testFalse() {
+    Assert.assertFalse(AwkStringMixin.canBeFunctionName(" \"aaa\" "));
+    Assert.assertFalse(AwkStringMixin.canBeFunctionName("\"111\""));
+    Assert.assertFalse(AwkStringMixin.canBeFunctionName("\"1aaa\""));
+    Assert.assertFalse(AwkStringMixin.canBeFunctionName("\"_aa a01\""));
+    Assert.assertFalse(AwkStringMixin.canBeFunctionName("\"Xxx'123\""));
+    Assert.assertFalse(AwkStringMixin.canBeFunctionName("\"-\""));
+    Assert.assertFalse(AwkStringMixin.canBeFunctionName("\"aaaa\\\"bbb\""));
+  }
+}

src/test/testData/inspection/funcRefToPreventUnusedFunc1.awk

@@ -0,0 +1,5 @@
+BEGIN {
+    PROCINFO["sorted_in"] = "compare"
+}
+
+function <caret>compare() {}

src/test/testData/inspection/funcRefToPreventUnusedFunc1_1.awk

@@ -0,0 +1,5 @@
+BEGIN {
+    PROCINFO["sorted_in"] = "compare1"
+}
+
+function <caret>compare() {}

src/test/testData/inspection/funcRefToPreventUnusedFunc1_1After.awk

@@ -0,0 +1,4 @@
+BEGIN {
+    PROCINFO["sorted_in"] = "compare1"
+}
+

src/test/testData/inspection/funcRefToPreventUnusedFunc2.awk

@@ -0,0 +1,6 @@
+BEGIN {
+    F = "fname"
+    @F()
+}
+
+function <caret>fname() {}

src/test/testData/inspection/funcRefToPreventUnusedFunc2_1.awk

@@ -0,0 +1,6 @@
+BEGIN {
+    F = "aaa fname bbb"
+    @F()
+}
+
+function <caret>fname() {}

src/test/testData/inspection/funcRefToPreventUnusedFunc2_1After.awk

@@ -0,0 +1,5 @@
+BEGIN {
+    F = "aaa fname bbb"
+    @F()
+}
+

src/test/testData/inspection/funcRefToPreventUnusedFunc3.awk

@@ -0,0 +1,5 @@
+BEGIN {
+    print a = "fname"
+}
+
+function <caret>fname() {}

src/test/testData/inspection/funcRefToPreventUnusedFunc3_1.awk

@@ -0,0 +1,5 @@
+BEGIN {
+    print "fname"
+}
+
+function <caret>fname() {}

src/test/testData/inspection/funcRefToPreventUnusedFunc3_1After.awk

@@ -0,0 +1,4 @@
+BEGIN {
+    print "fname"
+}
+

src/test/testData/inspection/funcRefToPreventUnusedFunc4.awk

@@ -0,0 +1,7 @@
+BEGIN {
+    b("fname")
+}
+
+function b(f) { @f() }
+
+function <caret>fname() {}

src/test/testData/inspection/funcRefToPreventUnusedFunc4_1.awk

@@ -0,0 +1,5 @@
+BEGIN {
+    length("fname")
+}
+
+function <caret>fname() {}

src/test/testData/inspection/funcRefToPreventUnusedFunc4_1After.awk

@@ -0,0 +1,5 @@
+BEGIN {
+    length("fname")
+}
+
+<caret>

src/test/testData/parser/BuiltInFuncSpace.txt

@@ -21,7 +21,8 @@ AWK File
                     PsiElement(AwkTokenType.()('(')
                     AwkGawkFuncCallListImpl(GAWK_FUNC_CALL_LIST)
                       AwkNonUnaryExprImpl(NON_UNARY_EXPR)
-                        PsiElement(AwkTokenType.STRING)('"abc"')
+                        AwkStrImpl(STR)
+                          PsiElement(AwkTokenType.STRING)('"abc"')
                       PsiElement(AwkTokenType.,)(',')
                       AwkNonUnaryExprImpl(NON_UNARY_EXPR)
                         PsiElement(AwkTokenType.NUMBER)('2')

src/test/testData/parser/UserFuncSpace.txt

@@ -46,7 +46,8 @@ AWK File
             AwkNonUnaryExprImpl(NON_UNARY_EXPR)
               PsiElement(AwkTokenType.()('(')
               AwkNonUnaryExprImpl(NON_UNARY_EXPR)
-                PsiElement(AwkTokenType.STRING)('"A"')
+                AwkStrImpl(STR)
+                  PsiElement(AwkTokenType.STRING)('"A"')
               PsiElement(AwkTokenType.))(')')
       PsiWhiteSpace(' ')
       PsiElement(AwkTokenType.})('}')

src/test/testData/rename/funcRef.awk

@@ -0,0 +1,8 @@
+BEGIN {
+    a = "fname"
+    b("fname")
+    substr("fname")
+    print "fname"
+}
+function b() {}
+function fname<caret>() {}

src/test/testData/rename/funcRefAfter.awk

@@ -0,0 +1,8 @@
+BEGIN {
+    a = "newName"
+    b("newName")
+    substr("fname")
+    print "fname"
+}
+function b() {}
+function newName<caret>() {}