Fix float associativity bug with addition

Author: jaskarth

src/org/jetbrains/java/decompiler/modules/decompiler/exps/FunctionExprent.java

@@ -737,7 +737,10 @@ private TextBuffer wrapOperandString(Exprent expr, boolean eq, int indent, boole
       if (parentheses) {
         if (expr instanceof FunctionExprent &&
             ((FunctionExprent)expr).getFuncType() == funcType) {
-          parentheses = !ASSOCIATIVITY.contains(funcType);
+          // Float operations are not assocative!
+          if (expr.getExprType() != VarType.VARTYPE_FLOAT && expr.getExprType() != VarType.VARTYPE_DOUBLE) {
+            parentheses = !ASSOCIATIVITY.contains(funcType);
+          }
         }
       }
     }

test/org/jetbrains/java/decompiler/SingleClassesTest.java

@@ -614,8 +614,6 @@ private void registerDefault() {
     // TODO: test2 now successfully triggers the bug in Vineflower
     register(JAVA_8, "TestTryVar");
     register(JAVA_8_NODEBUG, "TestTryVarNoDebug");
-    // TODO: order of additions is wrong. Addition over floats isn't associative.
-    // Derived from IDEA-291735
     register(JAVA_8, "TestFloatOrderOfOperations");
     // TODO: not simplifying to `+=`
     register(JAVA_8, "TestMixedCompoundAssignment");
@@ -651,7 +649,6 @@ private void registerDefault() {
     register(SCALA, "TestCompanionObject", "TestCompanionObject$");
     // TODO: foreach array index increment is added into default branch of switch statement
     register(JAVA_8, "TestForeachMultiDimensionalArray");
-    // TODO: <unknown> value and cast, switch is eliminated, test2 contains entirely invalid code
     register(JAVA_17_PREVIEW, "TestUnknownCastJ17");
     // TODO: These variables shouldn't be merged, and should be split because each version is used once and has a different type use
     register(JAVA_8_NODEBUG, "TestVarIndex");

testData/results/pkg/TestFloatOrderOfOperations.dec

@@ -2,7 +2,7 @@ package pkg;
 
 public class TestFloatOrderOfOperations {
    public float test(float a, float b, float c) {
-      return a + b + c;// 5
+      return a + (b + c);// 5
    }
 
    public float testReference(float a, float b, float c) {
@@ -32,4 +32,4 @@ class 'pkg/TestFloatOrderOfOperations' {
 
 Lines mapping:
 5 <-> 5
-9 <-> 9
+9 <-> 9