- Error message with hashmap shows "mangled" name instead of original #2562.

releasenotes.md

@@ -15,6 +15,7 @@
 - Fix division-by-zero checks on `a /= 0` and `b /= 0f` #2558.
 - Fix fmod `a %= 0f`.
 - Regression vector ABI: initializing a struct containing a NPOT vector with a constant value would crash LLVM. #2559
+- Error message with hashmap shows "mangled" name instead of original #2562.
 
 ### Stdlib changes
 

src/compiler/types.c

@@ -355,7 +355,14 @@ static const char *type_to_error_string_with_path(Type *type)
 			Decl *decl = type->decl;
 			const char *suffix = decl->unit->module->generic_suffix;
 			scratch_buffer_clear();
-			scratch_buffer_append(decl->unit->module->name->module);
+			if (decl->unit->module->generic_module)
+			{
+				scratch_buffer_append(decl->unit->module->generic_module->name->module);
+			}
+			else
+			{
+				scratch_buffer_append(decl->unit->module->name->module);
+			}
 			scratch_buffer_append("::");
 			if (suffix || type_is_inner_type(type))
 			{

test/test_suite/generic/generic_error_out.c3

@@ -0,0 +1,10 @@
+module test;
+import std::collections::map;
+
+fn void foo(HashMap{char[], String}* f) { }
+
+fn void main()
+{
+	HashMap{char[], char[]} x;
+	foo(&x); // #error: Implicitly casting 'std::collections::map::HashMap{char[], char[]}*' to 'std::collections::map::HashMap{char[], String}*' is not permitted, but you may do an explicit cast by placing '(std::collections::map::HashMap{char[], String}*)' before the expression
+}