Merge pull request #3572 from nordlow/better-range-diag

More readable message in ArrayIndexError

Author: RazvanN7

src/core/exception.d

@@ -97,7 +97,7 @@ class ArrayIndexError : RangeError
         this.length = length;
 
         // Constructing the message is a bit clumsy:
-        // It's essentially `printf("index [%zu] exceeds array of length [%zu]", index, length)`,
+        // It's essentially `printf("index [%zu] is out of bounds for array of length [%zu]", index, length)`,
         // but even `snprintf` isn't `pure`.
         // Also string concatenation isn't `@nogc`, and casting to/from immutable isn't `@safe`
         import core.internal.string : unsignedToTempString;
@@ -107,7 +107,7 @@ class ArrayIndexError : RangeError
         sink.rangeMsgPut("index [");
         sink.rangeMsgPut(unsignedToTempString!10(index, tmpBuf));
         sink.rangeMsgPut("]");
-        sink.rangeMsgPut(" exceeds array of length ");
+        sink.rangeMsgPut(" is out of bounds for array of length ");
         sink.rangeMsgPut(unsignedToTempString!10(length, tmpBuf));
         this.msgBuf = buf;
         super(msgBuf[0..$-sink.length], file, line, next);
@@ -116,7 +116,7 @@ class ArrayIndexError : RangeError
 
 @safe pure unittest
 {
-    assert(new ArrayIndexError(900, 700).msg == "index [900] exceeds array of length 700");
+    assert(new ArrayIndexError(900, 700).msg == "index [900] is out of bounds for array of length 700");
     // Ensure msg buffer doesn't overflow on large numbers
     assert(new ArrayIndexError(size_t.max, size_t.max-1).msg);
 }