fix regression compiler crash in string comparison

compiler/src/prog8/compiler/astprocessing/LiteralsToAutoVars.kt

@@ -27,7 +27,11 @@ internal class LiteralsToAutoVars(private val program: Program,
             errors.err("compilation target doesn't support this text encoding", string.position)
             return noModifications
         }
-        if(string.parent !is VarDecl && string.parent !is WhenChoice && string.parent !is BinaryExpression) {
+        if(string.parent !is VarDecl && string.parent !is WhenChoice) {
+            val binExpr = string.parent as? BinaryExpression
+            if(binExpr!=null &&(binExpr.operator=="+" || binExpr.operator=="*"))
+                return noModifications // allow string concatenation or repeats later, based on just string literals
+
             // replace the literal string by an identifier reference to the interned string
             val parentFunc = (string.parent as? IFunctionCall)?.target
             if(parentFunc!=null) {

compiler/test/TestOptimization.kt

@@ -3,7 +3,6 @@ package prog8tests
 import io.kotest.assertions.fail
 import io.kotest.assertions.withClue
 import io.kotest.core.spec.style.FunSpec
-import io.kotest.matchers.collections.shouldStartWith
 import io.kotest.matchers.shouldBe
 import io.kotest.matchers.shouldNotBe
 import io.kotest.matchers.string.shouldContain
@@ -753,7 +752,6 @@ class TestOptimization: FunSpec({
             }
         }"""
         val result = compileText(C64Target(), optimize=true, src, writeAssembly=false)!!
-        printProgram(result.program)
         val stmts = result.program.entrypoint.statements
         stmts.size shouldBe 5
         val ifStmt = stmts[4] as IfElse

compiler/test/ast/TestVarious.kt

@@ -3,9 +3,15 @@ package prog8tests.ast
 import io.kotest.core.spec.style.FunSpec
 import io.kotest.matchers.shouldBe
 import io.kotest.matchers.shouldNotBe
+import prog8.ast.IFunctionCall
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.StringLiteral
+import prog8.ast.statements.Assignment
 import prog8.ast.statements.InlineAssembly
+import prog8.ast.statements.VarDecl
 import prog8.code.core.Position
 import prog8.code.target.C64Target
+import prog8.compiler.printProgram
 import prog8tests.helpers.compileText
 
 class TestVarious: FunSpec({
@@ -61,5 +67,53 @@ main {
 }"""
         compileText(C64Target(), false, text, writeAssembly = false) shouldBe null
     }
+
+    test("simple string comparison still works") {
+        val src="""
+        main {
+            sub start() {
+                ubyte @shared value
+                str thing = "????"
+        
+                if thing=="name" {
+                    value++
+                }
+        
+                if thing!="name" {
+                    value++
+                }
+            }
+        }"""
+        val result = compileText(C64Target(), optimize=false, src, writeAssembly=true)!!
+        val stmts = result.program.entrypoint.statements
+        stmts.size shouldBe 6
+    }
+
+    test("string concatenation and repeats") {
+        val src="""
+        main {
+            sub start() {
+                str @shared name = "part1" + "part2"
+                str @shared rept = "rep"*4
+                const ubyte times = 3
+                name = "xx1" + "xx2"
+                rept = "xyz" * (times+1)
+            }
+        }"""
+        val result = compileText(C64Target(), optimize=false, src, writeAssembly=true)!!
+        printProgram(result.program)
+        val stmts = result.program.entrypoint.statements
+        stmts.size shouldBe 6
+        val name1 = stmts[0] as VarDecl
+        val rept1 = stmts[1] as VarDecl
+        (name1.value as StringLiteral).value shouldBe "part1part2"
+        (rept1.value as StringLiteral).value shouldBe "reprepreprep"
+        val name2strcopy = stmts[3] as IFunctionCall
+        val rept2strcopy = stmts[4] as IFunctionCall
+        val name2 = name2strcopy.args.first() as IdentifierReference
+        val rept2 = rept2strcopy.args.first() as IdentifierReference
+        (name2.targetVarDecl(result.program)!!.value as StringLiteral).value shouldBe "xx1xx2"
+        (rept2.targetVarDecl(result.program)!!.value as StringLiteral).value shouldBe "xyzxyzxyzxyz"
+    }
 })
 

docs/source/todo.rst

@@ -3,7 +3,6 @@ TODO
 
 For next release
 ^^^^^^^^^^^^^^^^
-- fix compiler crash when comparing strings
 - make it possible to inline non-asmsub routines that just contain a single statement (return, functioncall, assignment)
   Only if the arguments are simple expressions, and the inlined subroutine cannot contain further nested subroutines!
   This requires all identifiers in the inlined expression to be changed to fully scoped names (because their scope changes).