Enable -checkaction=context by default

changelog/checkaction-context-default.dd

@@ -0,0 +1,15 @@
+Enhanced `assert` informations are now printed by default
+
+Starting from this release, DMD will now print rich informations on assert failures.
+For example, the following code:
+---
+void main ()
+{
+    int a = 0, b = 42;
+    assert(a == b);
+}
+---
+
+Will now print: `core.exception.AssertError@filename.d(4): 0 != 42`.
+This behavior was previously accessible via the CLI switch `-checkaction=context`.
+To revert to the old behavior, use `-checkaction=D`.

src/dmd/globals.d

@@ -75,10 +75,10 @@ enum CHECKENABLE : ubyte
 
 enum CHECKACTION : ubyte
 {
+    context,      // call D assert with the error context on failure
     D,            // call D assert on failure
     C,            // call C assert on failure
     halt,         // cause program halt on failure
-    context,      // call D assert with the error context on failure
 }
 
 enum CPU
@@ -248,7 +248,8 @@ extern (C++) struct Param
     CHECKENABLE useSwitchError = CHECKENABLE._default;  // check for switches without a default
     CHECKENABLE boundscheck    = CHECKENABLE._default;  // state of -boundscheck switch
 
-    CHECKACTION checkAction = CHECKACTION.D; // action to take when bounds, asserts or switch defaults are violated
+    /// Action to take when bounds, asserts or switch defaults are violated
+    CHECKACTION checkAction = CHECKACTION.context;
 
     uint errorLimit = 20;
 

src/dmd/globals.h

@@ -67,10 +67,10 @@ enum
 typedef unsigned char CHECKACTION;
 enum
 {
+    CHECKACTION_context,  // call D assert with the error context on failure
     CHECKACTION_D,        // call D assert on failure
     CHECKACTION_C,        // call C assert on failure
-    CHECKACTION_halt,     // cause program halt on failure
-    CHECKACTION_context   // call D assert with the error context on failure
+    CHECKACTION_halt      // cause program halt on failure
 };
 
 enum class CPU