Add inspection for duplicate local variable/parameters

Author: waleedyaseen

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- Add an inspection for checking duplicate local variables and parameters.
+
 ### Fixed
 
 - Fix project opening not working as expected in IntelliJ 2023 builds.

src/main/kotlin/io/runescript/plugin/ide/inspections/RuneScriptDuplicateLocalVariableInspection.kt

@@ -0,0 +1,73 @@
+package io.runescript.plugin.ide.inspections
+
+import com.intellij.codeInspection.LocalInspectionTool
+import com.intellij.codeInspection.ProblemHighlightType
+import com.intellij.codeInspection.ProblemsHolder
+import com.intellij.psi.PsiElementVisitor
+import com.intellij.psi.ResolveState
+import io.runescript.plugin.ide.RsBundle
+import io.runescript.plugin.lang.psi.RsArrayVariableDeclarationStatement
+import io.runescript.plugin.lang.psi.RsLocalVariableDeclarationStatement
+import io.runescript.plugin.lang.psi.RsLocalVariableExpression
+import io.runescript.plugin.lang.psi.RsParameter
+import io.runescript.plugin.lang.psi.RsVisitor
+import io.runescript.plugin.lang.psi.scope.RsLocalVariableResolver
+import io.runescript.plugin.lang.psi.scope.RsResolveMode
+import io.runescript.plugin.lang.psi.scope.RsScopesUtil
+
+class RuneScriptDuplicateLocalVariableInspection : LocalInspectionTool() {
+
+    override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean): PsiElementVisitor {
+        return object : RsVisitor() {
+
+            override fun visitParameter(o: RsParameter) {
+                val name = o.localVariableExpression.name ?: return
+                var prev = o.prevSibling
+                while (prev != null) {
+                    if (prev is RsParameter) {
+                        val prevName = prev.localVariableExpression.name
+                        if (name == prevName) {
+                            holder.registerProblem(
+                                o.localVariableExpression,
+                                RsBundle.message("inspection.error.duplicate.parameter", name),
+                                ProblemHighlightType.GENERIC_ERROR
+                            )
+                            break
+                        }
+                    }
+                    prev = prev.prevSibling
+                }
+            }
+
+            override fun visitLocalVariableDeclarationStatement(o: RsLocalVariableDeclarationStatement) {
+                val prev = o.prevSibling ?: o.parent ?: return
+                val expr = o.expressionList[0] as RsLocalVariableExpression
+                val name = expr.name ?: return
+                val resolver = RsLocalVariableResolver(name, RsResolveMode.Variables)
+                RsScopesUtil.walkUpScopes(resolver, ResolveState.initial(), prev)
+                if (resolver.declaration != null) {
+                    holder.registerProblem(
+                        expr,
+                        RsBundle.message("inspection.error.duplicate.local.variable", name),
+                        ProblemHighlightType.GENERIC_ERROR
+                    )
+                }
+            }
+
+            override fun visitArrayVariableDeclarationStatement(o: RsArrayVariableDeclarationStatement) {
+                val prev = o.prevSibling ?: o.parent ?: return
+                val expr = o.expressionList[0] as RsLocalVariableExpression
+                val name = expr.name ?: return
+                val resolver = RsLocalVariableResolver(name, RsResolveMode.Arrays)
+                RsScopesUtil.walkUpScopes(resolver, ResolveState.initial(), prev)
+                if (resolver.declaration != null) {
+                    holder.registerProblem(
+                        expr,
+                        RsBundle.message("inspection.error.duplicate.array.variable", name),
+                        ProblemHighlightType.GENERIC_ERROR
+                    )
+                }
+            }
+        }
+    }
+}

src/main/resources/META-INF/inspections.xml

@@ -24,6 +24,12 @@
                          enabledByDefault="true"
                          level="ERROR"
                          implementationClass="io.runescript.plugin.ide.inspections.RuneScriptUnresolvedLocalVariableInspection"/>
+        <localInspection language="RuneScript"
+                         groupName="RuneScript"
+                         displayName="Duplicate local variable"
+                         enabledByDefault="true"
+                         level="ERROR"
+                         implementationClass="io.runescript.plugin.ide.inspections.RuneScriptDuplicateLocalVariableInspection"/>
         <localInspection language="RuneScript"
                          groupName="RuneScript"
                          displayName="Unresolved game variable"

src/main/resources/inspectionDescriptions/RuneScriptDuplicateLocalVariable.html

@@ -0,0 +1,5 @@
+<html>
+<body>
+<p>Reports a local variable that is declared multiple times in the same scope.</p>
+</body>
+</html>

src/main/resources/messages/RsBundle.properties

@@ -61,6 +61,9 @@ inspection.error.trigger.parameter.list.not.allowed=Trigger type `{0}` does not
 inspection.error.trigger.subject.not.found=Unresolved subject `{0}` of type `{1}`
 inspection.error.script.symbol.not.found=Script symbol not found for `{0}`
 inspection.error.trigger.code.not.allowed=Trigger type `command` does not allow for code statements
+inspection.error.duplicate.parameter=Duplicate parameter `{0}`
+inspection.error.duplicate.local.variable=Duplicate local variable `{0}`
+inspection.error.duplicate.array.variable=Duplicate array local variable `{0}`
 
 # Intentions
 intention.category.expressions=RuneScript/Expressions