Allow is constraints on wildcarded parameters and locals

Closes #1166

Author: hsutter

.gitignore

@@ -37,3 +37,4 @@ venv/*
 # VSCode workspace directory
 .vscode/
 buildh2.bat
+gen_version.bat

regression-tests/pure2-type-constraints.cpp2

@@ -0,0 +1,18 @@
+
+print: (r: _ is std::regular) = {
+    std::cout << "satisfies std::regular\n";
+}
+
+print: (_) = {
+    std::cout << "fallback\n";
+}
+
+irregular: type = {}
+
+main: () = {
+    print(42);
+    print(irregular());
+
+    ok : _ is std::regular = 42;
+    //err: _ is std::regular = irregular();
+}

regression-tests/test-results/clang-12-c++20/pure2-type-constraints.cpp.execution

@@ -0,0 +1,2 @@
+satisfies std::regular
+fallback

regression-tests/test-results/clang-12-c++20/pure2-type-constraints.cpp.output

@@ -0,0 +1,2 @@
+satisfies std::regular
+fallback

regression-tests/test-results/gcc-10-c++20/pure2-type-constraints.cpp.execution

@@ -0,0 +1,2 @@
+satisfies std::regular
+fallback

regression-tests/test-results/gcc-10-c++20/pure2-type-constraints.cpp.output

@@ -9,26 +9,26 @@ Running tests_10_escapes:
 08_y: OK regex: foo(\h)bar parsed_regex: foo(\h)bar str: foo	bar result_expr: $1 expected_results 	
 09_y: OK regex: (\H)(\h) parsed_regex: (\H)(\h) str: foo	bar result_expr: $1-$2 expected_results o-	
 10_y: OK regex: (\h)(\H) parsed_regex: (\h)(\H) str: foo	bar result_expr: $1-$2 expected_results 	-b
-11_y: OK regex: foo(\v+)bar parsed_regex: foo(\v+)bar str: foo
+11_y: OK regex: foo(\v+)bar parsed_regex: foo(\v+)bar str: foo
+
 
+bar result_expr: $1 expected_results 
+
 
-bar result_expr: $1 expected_results 
 
+12_y: OK regex: (\V+)(\v) parsed_regex: (\V+)(\v) str: foo
+
 
+bar result_expr: $1-$2 expected_results foo-
+13_y: OK regex: (\v+)(\V) parsed_regex: (\v+)(\V) str: foo
+
 
-12_y: OK regex: (\V+)(\v) parsed_regex: (\V+)(\v) str: foo
-
-
-bar result_expr: $1-$2 expected_results foo-
-13_y: OK regex: (\v+)(\V) parsed_regex: (\v+)(\V) str: foo
-
-
-bar result_expr: $1-$2 expected_results 
-
+bar result_expr: $1-$2 expected_results 
+
 
 -b
-14_y: OK regex: foo(\v)bar parsed_regex: foo(\v)bar str: foobar result_expr: $1 expected_results 
-15_y: OK regex: (\V)(\v) parsed_regex: (\V)(\v) str: foobar result_expr: $1-$2 expected_results o-
+14_y: OK regex: foo(\v)bar parsed_regex: foo(\v)bar str: foobar result_expr: $1 expected_results 
+15_y: OK regex: (\V)(\v) parsed_regex: (\V)(\v) str: foobar result_expr: $1-$2 expected_results o-
 16_y: OK regex: (\v)(\V) parsed_regex: (\v)(\V) str: foobar result_expr: $1-$2 expected_results -b
 17_y: OK regex: foo\t\n\r\f\a\ebar parsed_regex: foo\t\n\r\f\a\ebar str: foo	
 bar result_expr: $& expected_results foo	

regression-tests/test-results/gcc-14-c++2b/pure2-type-constraints.cpp.execution

@@ -0,0 +1,2 @@
+satisfies std::regular
+fallback